Ex Libris C. K. OGDEN ^ ^■' AUTOMATIC SCREW MACHINES AND THEIR TOOLS AUTOMATIC SCREW MACHINES AND THEIR TOOLS BY C. L. GOODRICH Expert on Screw Machine Tools and Department Foreman of Pratt and Whilney Company; Author of "Accurate Tool Work" AND F. A. STANLEY Associate Editor American Machinist; Author of " American Machinists' Handbook," "Hill Kink Books" and "Accurate Tool Work" 1909 HILL PUBLISHING COMPANY 505 PEARL STREET, NEW YORK 6 BOUVERIE STREET, LONDON', E.G. Amirican Machinist — Pourr and The Engineer —The Engineering and Mining Journal Copyright, 1909, by The Hill Publishing Company Hill Publishing Company, New To>k, U.S.A. PREFACE In the preparation of this book on automatic screw machines and their tool eciuipment, we have endeavored to embody material which will constitute a comprehensive treatise for tool designers, toolmakers, and machine op(M"ators. The subject-matter of the book divides naturally into two sections, one devoted to various types of machines and their construction, general tool equipments, methods of camming, etc.; the other dealing with tools in detail, and containing specific information on making and using these tools, the speeds and feeds at which they should be operated, and other particulars which it is hoped may be of service to mechanics connected with screw machine work. The chapters on camming and on different types of cutting tools were prepared originally for publication in the columns of the Aiiierican Machi7iist; they are here arranged in some- what more convenient form of reference. It will be noted that in Section I a number of machines are included which, strictly speaking, are of the chucking machine type and "semi- automatic "' in their operation, the chucking of the work being accom- plished by hand. Aside from this feature, they are, broadly considered, similar in principle to the full automatic machines, although their capacity antl the method of holding the material adapt them to the machining of a heavier or otherwise different class of work from that usually produced on "automatics" working entirely from bar stock or on castings and forgings fed to the chuck by means of magazines. We recognize the fact that the name "automatic screw machine" is hardly broad enough for the designation of a machine which can pro- duce from the bar, from castings or from forgings, almost any symmetrical piece that may fall within the capacity of the chuck and turret traverse. However, the purpose for which this type of machine was originally con- ceived, naturally determined its title, and, although to-day the making of screws is but a small part of the work it accomplishes, it is still gen- erally known by its original name. A few makers, especially of the medium and larger sizes of machines, refer to them as automatic "turret lathes" and automatic "turret machines," and in the chapter headings we have followed the respective manufacturers' preferences in the matter. The Authors. 20001 51 CONTEXTS I II III IV V VI VII VIII IX X XI XII XIII XIV XV X\I XVII XVIII SECTION I PAGE The Pratt & Whitney Automatic Screw Machine 3 Camming the Pratt it Whitney Automatic Screw Machine . . 12 The Brown it Shari'e Automatic Screw Machine 37 Laying Out the Brown it Sharps Screw Machine Cams . . 52 The Brown it Sharpe Automatic Screw Machine with Constant- Speed Drive 64 The Cleveland Automatic Turret Machine and Its Cam Adjust- ments 67 The Gridley Automatic Turret Lathe 78 The Alfred Herbert Automatic Screw Machine 89 The New Spencer Double-Turret Automatic Screw Machine . 91 The Cleveland Double-Spindle Plain Automatic Machine . . 93 The Acme Multiple-Spindle Automatic Screw Machine ... 95 The rNIVKRSAL MCLTII'LH-SPINDLE AUTOMATIC ScREW MaCHI.NE . 114 The Cridley Multiple-Spindle Automatic Turret Lathe . . 119 The Cleveland Auto.matic M.vchine with Magazine Attachment 126 The Alfred Herbert Macjazine .\utomatic Screw .Machine . . 128 The Potter rev. 3d tool. Travel of turret, 0.62.")" at 0.010 feed per revolution = 02..5 rev. 4th tool. 1st part of travel of turret, 0..59.37" at 0.015 feed per revolution = 39.5 rev. 2d part of travel of turret, 0.0312" at 0.005 feed per revolution = 6.2 rev. Indexing. Travel of turret. 6.5" at 0.04 feed per revolution = 162. 5 rev. Total number of revolutions nece.ssary = 520.7 Table 2. — Spindle Revolutions Required in Making Piece Shown in Fig. 9 Thus we find that for the 25.39 inches of drum periphery available for the cams to be figured, the spindle should make 521 turns, or 20.5 turns for each inch of cam-drum space. This spindle velocity per inch of drum space will be approximated very closely by using on the counter- shaft a 10-inch driving drum for the spindle and a 6-inch pulley for driv- ing the feed motion. The question of spindle and feed-pulley ratios is discussed more fully later on. Knowing the feed per revolution for each tool, we find the angle for the cam for that tool by multiplying the rate of feed by 20.5 which gives the tangent of the desired angle. The angles for the various cams are then as follows: First tool. 0.004" feed X 20.5 = 0.082 = tangent of 4° 42' Second tool. 0.005" feed X 20.5 = 0.1025 = tangent of 5° 51' Third tool. 0.010" feed X 20.5 = 0.205 = tangent of 11° 36' Fourth tool. 0.015" feed X 20.5 = 0.3075 = tangent of 17° 5' Fourth tool. 0.005" feed X 20.5 = 0.1025 = tangent of 5° 51' Indexing. 0.04" feed X 20.5 = 0.82 = tangent of 39° 21' Table 3. — Cutting and Indexing Cam Angles The angles having been doternuned, the cams may now be laid out on the full-size drawing, a space n. Fig. S, equal to the roll tliameter plus ^-inch clearance being left between the adjacent cams, and the flats of ^-inch which prevent wearing of the cam corners being left on the working ends of each cam. A layout of these cams to a larger scale (about ^ actual size) is presented in Fig. 10, and in this drawing the angles of the 18 CAMMING THE PRATT & WHITNEY AUTOMATIC SCREW MACHINE cams are all shown. While these angles are given in degrees and min- utes, the nearest half degree is sufficiently close in practice. It may be of interest at this point, before considering the forming and cut-off cams, to show diagrammatically how the cam-drum surface is divided among the various cams which have been just laid out. For this purpose Figs. 11 to 15 inclusive have been drawn, although of course such diagrams would not be actually used in the working out of the camming problem. The portions of the 50-degree cams used in the foregoing calculations are here shown transferred below to the similar drum surface in Fig. 11, where a series of triangles 1, 2, 3, 4, 5, etc., are drawn which when ar- ranged in the order shown in Fig. 12 indicate the forward and backward movement of the turret due to that portion of the 50-degree cams which entered into the previous calculation, giving OjV inches. The 18-inch vertical line on which this 9^^ iiich travel is laid off represents the total travel of the turret back and forth between the lines i and / or 8 X 2^ inches. Hence the 8|| inch portion of that line represents that amount of turret travel due to the cutting and index cams. Fig. 13 is drawn to double the scale of the other diagrams to show more clearly the flats and roll spaces. Figs. 14 and 15 show the eight roll spaces and the cam fiats added to the peripheral distance utilized by the 50-degree cams, and the latter sketch indicates the amount of drum space actually left for the cut- ting cams and the index cams, which has previously been found to be 25.39 inches. FINDING THE CAM ANGLES GRAPHICALLY If preferred, the angles of the various cams may be obtained without reference to tables of trigonometrical functions. Although this method of finding the angles is very convenient, many will prefer the method given below \Vhich does not involve the use of trigonometry. A hint of this is given in Fig. 12. Say we draw a perpendicular line .1, Fig. 16, on the drawing board 9iV inches long, representing the to-an-fro travel between lines i and I by 50-degree cams, then draw a horizontal base line B, to which we draw a line C, from the top of the vertical line forming an angle of 50 degrees with the horizontal base line. The portion of the latter thus cut off will indicate the space measured around the drum which the 50-degree cams between lines i and I occupy, or 7.61 inches which can be measured with a scale accurately enough for all prac- tical purposes. Next we wish to determine the peripheral distance occupied by each cam-roll space and can find this by a similar process of laying out the roll between the ends of two cams as at D, in Fig. 17. If the layout is made double or four times the actual size, the result obtained by scaling will be more accurate and in fact quite near enough to the figured distance. Multiplying the distance D by 8 will give us the space required by the / p # how the Turret-Slide Drum Surface is UtiliKed by Ibe VarlouB CamB, Roll Spaces, ( n\ FINDING THE CA.Nl ANGLES (JKAPllICALLY 19 loox Jp to 20 CAMMING THE PRATT & ^VHTTNEY AUTOMATIC SCREW MACHINE eight cam-roll spaces, and adding this to 7.61 inches plus 2 inches for the eight ^-inch flats on the cam ends gives us the total amount to subtract from 48 inches (the circumference of the tlrum) to obtain the amount left for the cutting and indexing cams (or 25.39 inches). We have already found that the spindle makes 521 turns during the travel of the drum through a distance of 25.89 inches, or 20.5 turns per inch of drum travel. By referring back to our figures in Table 2, we see that the first tool will require 62.5 revolutions in feeding its distance of 0.250 inch toward the chuck at 0.004 inch per revolution. In other words, this tool will require a drum travel of (62.5 divided by 20.5) or 3.05 inches. Laying off a line of this length as E, in Fig. 18, and drawing a perpendicular of 0.250 inch to represent the feed distance, we have then mereh' to measure the angle with the protractor which will give us at once the correct angle for this cam. The angles of all the other cams may be obtained by a sim- ilar process, the side F of the triangle laid out representing the total feed or turret-slide travel required for the cam in question, and the length E representing the distance in inches which the drum travels while the spindle is making the number of revolutions necessary for that particular operation, as shown by Table 2. As suggested, it will be well to make the layout double size or larger, thus minimizing the' possibility of error in scaling the lines and measuring the angle. THE FORMIXG AND CUTTING-OFF CAMS Returning now to the forming and cutting-off cams, Fig. 8 shows these members laid out on the opposite sides of their disk. The forming tool cuts down the neck and fillet at the rear of the piece Fig. 9 and should be fed at about 0.002 inch per revolution, the operation being performed at the same tinie as the drilling. We have found that the spindle makes 20.5 revolutions to every inch of turret-slide drum travel, and this means that in a forming movement of ^ inch or 0.125 inch at 0.002 inch per turn, we require 62^ revolutions, which is ec^uivalent practically to 3 inches of drum travel. Laying off this amount on the drum T, we can run the radial lines indicated to the center of the cam disk to define the limits of the forming cam o. Li drawing the working edge of the cam we strike a curve giving a throAV somewhat greater than ^ inch, according to the location of the pin on which the cross-slide operating arms are pivoted. Thus, if the upper end of the rocker arm is f the length of the lower, it means practically that for every 0.001 advance of the cam slide the lower end of the arm must move outward about 0.0013 inch. The forming movement of 0.125 inch requires then a cam throw of 0.1625. In cutting off the completed work a feed of about 0.0025 inch per revolution will be suitable. If the thickness of the metal plus a reason- able amount for clearance, etc., is equal to | inch, the work will make SPINDLE DPJ'M AND FEED PULLEY CONSIDERATIONS 21 50 revolutions during the operation; at 20.5 revolutions of the spindle per inch of turret-slide drum travel tiie travel of the drum during the operation of the cut-off cams will be approximately 22 inches. This operation may commence at or slightly before the completion of the finish counterboring as shown in Fig. 8, where the cut-off cam ;) is drawn in on its side of the disk in the same manner as the forming cam just described. With the cam slide levers pivoted at the point mentioned in connection with the forming cam the cut-off movement of ^ inch will require a cam throw of about 0.166 inch. It will be obvious that the turret-slide drum must have sufficient .space between the points where the cut-off operation is completed and the first operation on the next piece is commenced to allow for the opening of the chuck, the feeding of the stock, and the locking up of the chuck on the work. This distance is indicated cleaily in Fig. 8. In putting the cams on the turret-slide drum the correct starting posi- tion for the first cam can be easily located by squaring across from the locking-up cam on the chucking drum, which cam must close the chuck tight before the first tool is brought quite into working position. Where a stop is used in the first hole in the turret the stop cam on the drum is so located relatively to the chucking cams as to bring the stop to its extreme forward position just before the stock is fed completely out and the chuck closed. SPIXDLE DRUM A\D FEED PULLEY COXSIDERATIOXS In the preceding matter it has been shown that after subtracting from the circumference of the turret-slide drum the peripheral space occupied by the 50-degree, or non-cutting and non-indexing cams, the eight cam- roll spaces and the eight ^-inch flats on the cam ends, we have left a cer- tain distance available for the cutting and indexing cams whose angles have to be figuretl or obtained by layout and measurement. We have found, too, that during the rotation of the drum through a certain dis- tance equal to the space occupied by these cams, the spindle should make a certain number of revolutions (as per Table 2) determined by adding up the number of turns nece.ssar}' for taking the different turret-tool cuts at the desired rates of speed, plus the turns during the indexing movements. In order, therefore, that the spindle and cam drum shall be driven at the proper relative speeds, with any given ratio of gearing in the feed motion, the question of the relative diameters of the spindle- driving drum on the countershaft and the feed-motion driving pulley on the same counter has to be taken into consideration. For it is obvious that, both spindle and feed motion being belted from the one counter- shaft, if we are using say a certain diameter of counter drum for driving 22 CAMMING THE PRATT A- WHITNEY AUTOMATIC SCREW MACHINE the spindle, any change in the size of pulley for driving the feed motion will affect the rate of turret-slide feed per revolution of spindle. SPINDLE AXD FEED-DRIVE RATIOS In Fig. 19 is shown by diagram the arrangement of pulleys on counter- shaft, spindle, and feed motion, ,4. being the drum for dri^•ing the spindle in either direction through reversing belts running on spindle pulley B, which is located between two loose pulleys; C is the countershaft pulley (known as the "feed pulley") for driving the cam-drum shaft D through pulley E, which operates the worm shaft and worm gear F at slow speed through the planetary gearing indicated at G, or directly at high speed by a clutch connecting the pulley directly to the worm shaft. On the No. 1 machine, for example, the spindle pulley B has a diameter of 6f inches, and the feed-motion pulley £" is 6 inches. The worm gear has 84 teeth meshing with a triple-thread worm, and 28 turns of the worm shaft are required to drive the cam shaft and cam drums through one complete c Counter — -1 Shaft _ - Center ol Spindle J Cam Shaft vfi D Fig. 19. — Diagram of Spindle and Cam- shaft Drive revolution. With a 24 to 1 ratio of gearing in the feed drive at G, it is obvious that the pulley E must turn 24 X 28 times, or 672 turns to each revolution of the drum shaft — assuming, of course, that the slow mo- tion (24 to 1) is in operation throughout the complete cycle. The cir- cumference of the turret-slide drum H carried by the latter being 48 inches, for each inch of peripheral travel of the drum, the pulley E on the feed drive must turn (672 -^ 48) = 14 revolutions. If we have (as found in connection with Table 2) a peripheral distance of 25. .39 inches to travel during 521 turns of the spindle in order to give the required feeds with the cams, as figured out, the spindle must make 20.5 revolutions for each inch of drum travel. That is, while pulley E, Fig. 19, is making 14 revo- lutions, pulley B must make 20.5 revolutions. If the two pulleys were USE OF Tin: TABLES 23 of the same diameter, the diameter of the countershaft drum A and feed pulley C would of course be in the ratio of 20.5 to 14 or 1.46 to 1. The spindle pulley, however, is 6| inches diameter and the worm-shaft pulley K 6 inches; therefore the countershaft pulleys will be in the ratio of (20..5 X 6g) to (14 X 6) = 136 to 84, or a ratio of 1.62 to 1. This ratio will be approximated very closely by a spindle-driving drum of a diameter of 10 inches and a feed pulley of 6 inches. The foregoing matter has been presented in order to show the rela- tion existing between the speed of the spintUe and the speed of the cam- drum drive. In practice, the diameter of the feed pulley required to be used in conjunction with any given diameter of driving drum for the spindle may be more directly obtained by the aid of a simple table — like Table 4, 5, 6, or 7 on pages 29 to 32. After we have found our cam angles as already described, we may take the angle of any one of the'cutting cams and use this in connection with our table for finding the required size of feed pullcv. USE OF THE TABLES Referring now to Table 5. this table is arranged with cdlunnis for each feed-motion ratio from 24 to 1 down to 2.7 to 1. The quantities in these columns are obtained by dividing the tangent of the angles from 1 to 45 degrees in the second column by the feed-pulley constants 12.7, 5.91, etc., given at the heads of the respective columns. The feed-pulley con- stant, it should be noted, is equivalent to the numl)er of revolutions of the head spindle to each inch of peripheral travel of the turret drum, with the same diameter of pulleys on the counter for driving the spindle and the feed mechanism. As indicated by the formula at the bottom of the table, the feed per revolution tan. of angle feed pulley X feed-pulley constant counter drum and as the six columns under the respective i-atios are already worked out giving the efjuivalent of tan. of angle feed-pulley constant the feed per revolution foi* any cam angle with any given ratio of gearing in the feed motion is found by multiplying the (juantity opposite the angle and in the required colunm by the feed-imlley diameter and then dividing by the diameter of the counter drum driving the head spindle. Now, with a given diameter of counter drum for the spindle, and with the angle determined for any cam and the rate of feed given which we wish to })roduce with that cam, we can find the diameter of feed pulley required to proiluce that rate of feed l)y a formula as follows: 2i CAMMING THE PRATT & WHITNEY AUTOMATIC SCREW MACHINE Dia. feed pulley = feed per rev. X dia. counter drum tan. of angle \ feed-pulley constant/ As we have the ex^Dression tan. of angle feed-pulley constant already worked out in the table for the various angles, it is merely neces- sary to multiply the feed per revolution by the diameter of the drum for driving the spindle, and divide by the quantity opposite the cam angle under the proper column. Thus, if one of the cams in the set which we have already figured out is to give a rate of feed of 0.005 inch per turn of spindle (using the 24 to 1 ratio) the cam angle being practically 6 degrees, and if we are using a 10-inch drum on the countershaft for driving the spindle, we can find the size of the feed pulley recjuired by multiply- ing 0.005 X 10 = 0.05 and dividing by 0.00S27 (found opposite 6 degrees and in the 24 to 1 ratio column) = 6. Hence a 6-inch pulley is the proper size to use. It will be obvious that owing to the method used in deter- mining the angles of the set of cams for the turret-slide drum, it makes no difference whatsoever which cam is used as a basis for working out the feed-pulley diameter. Similar tables which are included for the other sizes of machines should be found of considerable value. FEED CHANGES The figures in the different ratio columns in Table 5 actually show the rates of feed per i-evolution of spindle which would be obtained if the feed pulley and spindle-driving drum on the countershaft were of the same diameter, and by following across the table on any horizontal line the possible variations obtainable by the six different ratios of gears for use in the feed mechanism will be clearly seen. The actual feed changes produced by different angles of cams and various sizes of feed pulleys and counter drum with a given ratio of gearing are shown by Tables 8 to 11. Table 9, for example, is worked out for the No. 1 automatic and for a 24 to 1 ratio of feed gearing, and it will be apparent from this talkie that very fine changes of feed are obtained with any given feed pulley and counter drum by slight modification in cam angles; the entire range, of course, being greatly increased when we introduce the gears of other ratios into the feed drive. It should be borne in mind that after the machine has been cammed in accordance with the method descril^ed, the rate of feed per turn of spindle derived from the cam may be increased or decreased by changing the gears in the feed motion without affecting the rate of turret-slide THE TAVO-SPEED SPINDLE DRIVE 25 travel during the indexing movement. This is due to the fact that the indexing is accomplished with the feed-motion pulley clutched direct to the cam shaft for driving the cam drum, that is, the "fast motion" is then in operation and this drives at a constant speed unless the feed pulley on the countershaft is changed, or the speed of the counter itself altered by shifting the position of the belt on the three-step driving cone. While the indexing cams are laid out for performing their work with the turret slide traveling at about 20 feet per minute, some departure may be allowed either way from this normal rate, such, for instance, as might be due to a slight change in diameter of feed pulleys. THE TWO-SPEED SPINDLE DRIVE It is quite common practice now, with the Pratt & Whitney automatic, to equip it with a two-step pulley for operating the head spindle in place of the single-diameter drum formerly used for this type of machine. This gives the spindle two rates of speed (ordinarily 2 to 1) and the higher speed is generally employed for the backing belt. Thus, a suitable countershaft speed may be selectetl for the rough turning cut and for threading, using the forward belt (except in very unusual cases where a left-hand thread is to be cut), and the fast backward speed is then utilized for finish turning and cutting off, a left-hand finishing box tool being used and the cut-off being carried on the rear end of the cross slide. If a forming tool is required, this is carried at the front of the cross slide and operated while the roughing box tool is cutting, with the spindle operating at its slow speed. The spindle then reverses upon the com- pletion of the rough-turning and the forming operation, and runs back- ward at double the forward speed while the finishing tool is in operation. If the piece is to be threaded, the slower forward speed is utilized while cutting; and after the die has run on, the spindle again reverses to high speed while the die is run off and tlie cut-off tool severs the work from the bar. This two-speed arrangement is a very advantageous one as it makes it possible to drive the spindle at speeds best adapted for the cuts taken by the different classes of tools used on the work, and thus greatly increases the output. In plotting out cam angles for use in connection with the two-spindle drive it is advisable to reduce all feeds per revolution to what they actu- ally would be in case only one of the two speeds was used, and thus simplify the problem. For example, if we have a constant feed of 0.005 inch per revolution at 100 revolutions per minute, and another constant feed of 0.005 inch at 200 revolutions per minute, it is advisable to consider both at the same number of revolutions per minute. To reduce the former to the latter = 0.005 inch X iS!} or 0.0025-inch feed at 200 revolutions per minute, 26 CAMMING THE PRATT c^- WHITNEY AUTOMATIC SCREW MACHINE while the latter would, of course, remain 0.005. The tangents of the angles for the cams to be used would, of course, be 2 to 1, while the actual feeds per revolution at the speeds used are equal. Fig. 20 shows a cam layout for a machine using the two-speed spindle drive, the turret-cam drum surface development being shown in two sections for convenience. The forming and cutting-off cams are sketched in at the side of the drum layout with the circles drawn to clearly indi- cate where the forming and cut-off operations commence and end. The cams shown are suitable for general screw work, the first cam A being a plain 50-degree stop cam which holds the turret in its forward position, while the stock feeds out. Cam B for the roughing-box tool, and the forming cam on the cross-slide disk, are in operation while the spindle runs at its slow speed, and cam C for the finishing cut feeds the finishing- box tool over the work with the spindle operating at its fast speed. The slow spindle speed is used while the die is run on by cam D, and the fast speed is again employed during the cutting-off operation. It will be no- ticed that extra space is left between the end of the die cam D and the last draw-back cam. This extra clearance is provided in order that the die may have ample time to run up on the screw and reverse before the draw-back cam comes into action against the turret-slide roll. Where an opening die is used, mounted in a sliding holder, the die cam may be made shorter as indicated by the dotted lines. The forming tool is used advantageously on regular screw work for necking down at each side of the head while the roughing-box tool is in operation. This reduces the work of the cutting-off tool and on many jobs relieves the box tool of the work of finishing the under side of the head. PUTTING ON THE CAMS A few words regarding the forming and placing of the cams in posi- tion on the drums and cut-off disk may not be out of place here. After the angles, lengths, etc., have been found the cams may be cut from the flat stock to the right length and proper angles at the ends by means of a saw in the milling machine, swiveling the vise to give the required angles for the ends, and then the holes for the tap bolts are drilled, after which the cams are bent to conform to the curvature of the drum. Tough steel that will admit of being hardened should be used, and after the pieces are hardened they are located one by one on the drum, and the latter drilled and the holes tapped for the tap bolts which secure the cams in place. The turret-slide cams are located in the right positions rela- tive to the chucking drum cams by squaring across from the chuck- closing cam on that drum, this giving the right location for the first cam on the turret-slide drum. It must be kept in mind that the chuck-closing cam must close the chuck completely before the cutting PITTING OX THE CAMS 27 28 CAMMING THE PRATT & WHITNEY AUTOMATIC SCREW MACHINE part of the first cam on the turret drum comes into contact with the cam roll. The forming and cutting-off cams are located on their disk so that the ends of these cams are just passing the ends of the cross-slide levers when the points on the turret cams marked in the layout "end of forming" and "end of cut-off" are just in contact with the turret-slide roll. The idea will be clear from the drawing in Fig. 20. PRATT & WHITNEY CAM AND FEED TABLES 29 P. & W. No. Automatic TANr.ENT OF ANGLE FEED PULLEY CONSTANT RATIOS Tangent .0174G .02619 .03492 .04366 .05241 .06993 .08749 .10510 .12278 .14054 .158.38 .17633 .19438 .21256 .23087 .24933 .26795 .28675 .30573 .32492 .34433 .36397 .3838(5 .40403 .42447 .44523 .46()31 .48773 .5095.3 .53171 .55431 .57735 .60086 .62487 .64941 .67451 .70021 .72654 .75355 .78129 .80978 .83910 .86929 .90040 .93252 .96569 1.00000 24:1 Feed Pulley Const. 37.3 .00046 .00070 .00093 .00117 .00140 .00187 .00234 .00282 .00329 .(K)376 .00424 .00472 .00521 .00569 .00618 .00668 .00718 .00768 .00819 .00871 .00922 .00975 .01029 .01083 .01137 .01193 .012.")() .01.^07 .()l(i34 .01425 .01486 .01547 .01610 .01675 .01741 .018.35 .01877 .01947 .02020 .02094 .02170 .02249 .0233 .0241 .0250 .0259 .0268 11.16:1 Feed Pulley Const. 17.35 .0010 .0015 .0020 .0025 .0030 .0040 .0050 .0060 .0071 .0081 .0091 .0101 .0112 .0122 .0133 .0143 .0154 .0165 .0176 .0187 .0198 .0209 .0221 .0233 .0244 .0255 .0268 .02S1 .0293 .0306 .0319 .0332 .0346 .0359 .0374 .0388 .0403 .0418 .0434 .0450 .0466 .0483 .0500 .0518 .0537 .0556 .0576 5.81:1 Feed Pulley Const. 9.03 .0019 .0029 .0039 .0048 .0058 .0078 .0096 .0116 .01.36 .0155 .0175 .0195 .0215 .0235 .0256 .0276 .0297 .0318 .0339 .0361 .0382 .0404 .0426 .0448 .0471 .0494 .0517 .0542 .0565 .0590 .0615 .0640 .0667 .0694 .0720 .0748 .0777 .0806 .0836 .0867 .0899 .0931 .0964 .0999 .1034 .1071 .1107 4:1 Feed Pulley Const. 0.22 .0027 .0042 .0056 .0069 .0084 .0113 .0140 .0169 .0198 .0225 .0254 .0283 .0312 .0341 .0372 .0401 .0431 .04(52 .0493 .0523 .0554 .0586 .0(5 IS .0;55() .0(587 .0716 .0750 .0786 .0819 .0856 .0892 .0929 .0968 .1006 .1045 .1085 .1127 .1169 .1212 .1257 .1304 .1351 .1.399 .1449 .1500 .1554 .1608 3.14:1 Feed Pulley Const. 4.88 .0035 .0053 .0072 .0088 .0107 .0143 .0178 .0215 .0252 .0287 .0324 .0361 .0398 .0435 .0473 .0510 .0549 .0588 .0627 .0666 .0705 .0746 .0787 .0828 .08(59 .0912 .0955 .1000 .1043 .1091 .1136 .1183 .1232 .1281 .1330 .1382 .14.35 .1488 .1544 .1601 .1660 .1720 .1781 .1845 .1911 .1978 .2049 Table 4. Correct Feed per one Revolution of Head Spindle = Tan, of Angle Feed Pulley Feed Pulley Const. Counter Drum For Findinp; the Correct Food per Rovolution of Spindle or the Diameter of Feed Pulley, for any f^iven Cam Aiiirle. No. Machine. 30 CAMMING THE PRATT & WHITNEY AUTOMATIC SCREW MACHINE P. ct W. No. 1 rOMATIC TANGENT OF ANGLE Au FEED PULLEY CONSTANT Tangent RATIOS w 24:1 11.16:1 5.81:1 4:1 3.1:1 2.7:1 Feed Feed Feed Feed Feed Feed w Pulley Pulley Pulley Pulley Pulley Pulley Const. Const. Const. Const. Const. Const. 12.7 5.91 3.07 2.18 1.64 1.43 1 .01746 .00137 .00295 .00568 .00800 .01084 .01220 1* .02619 .00206 .00443 .00853 .01201 .01596 .01831 2 .03492 .00274 .00591 .01137 .01601 .02129 .02441 2* .04366 .00343 .00738 .01422 .02002 .02662 .03053 3" .05241 .00412 .00886 .01707 .02404 .03195 .03665 4 .06993 .00550 .01183 .02277 .03207 .04264 .04897 5 .08749 .00688 .01480 .02849 .04013 .05334 .06118 6 .10510 .00827 .01778 .03423 .04821 .06408 .07350 7 .12278 .00966 .02077 .04000 .05401 .07608 .08586 8 .14054 .01106 .02378 .04577 .06447 .08569 .09828 9 .15838 .01247 .02679 .05158 .07265 .09655 .11075 10 .17633 .01388 .02983 .05687 .08000 .10648 .12200 11 .19438 .01530 .03289 .06331 .08916 .11852 .13593 12 .21256 .01673 .03596 .06923 .09750 .12961 .14864 13 .23087 .01817 .03906 .07520 .10590 .14077 .16144 14 .24933 .01963 .04218 .08122 .11437 .15203 .17435 15 .26795 .02109 .04533 .08728 .12291 .16338 .18737 16 .28675 .02257 .04851 .09340 .13153 .17487 .20053 17 .30573 .02407 .05173 .09959 .14024 .18642 .21380 18 .32492 .02558 .05494 .10583 .15863 .19812 .22721 19 .34433 .02711 .05995 .11216 .15795 .20996 .24078 20 .36397 .02865 .06158 .11855 .16695 .22193 .25453 21 .38386 .03022 .06495 .12503 .17608 .23406 .26843 22 .40403 .03181 .06836 .13160 .18533 .24635 .28253 23 .42447 .03342 .07182 .13826 .19470 .25882 .29613 24 .44523 .03505 .07533 .14502 .20423 .27148 .31135 25 .46631 .03671 .07890 .15189 .21390 .28433 .32609 26 .48773 .03761 .08252 .15887 .22372 .29739 .34107 27 .50953 .04012 .08621 .16600 .23373 .31069 .35631 28 .53171 .04186 .08996 .17319 .24390 .32421 .37183 29 .55431 , .04364 .09379 .18055 .25427 .33800 .38763 30 .57735 .04545 .09769 .18805 .26483 .35201 .40374 31 .60086 .04731 .10166 .19572 .27562 .36637 .42018 32 .62487 .04920 .10573 .20354 .28633 .38101 .43697 33 .64941 .05113 .10988 .21153 .29789 .39598 .45413 34 .67451 .05311 .11413 .21971 .30941 .41128 .47168 35 .70021 .05513 .11837 .22808 .32119 .42695 .48965 36 .72654 .05720 .12293 .23665 .33327 .44301 .50807 37 .75355 .05870 .12750 .24545 .34566 .45945 .52695 38 .78129 .06151 .13219 .25449 .35839 .47639 .54635 39 .80978 .06297 .13701 .26377 .37147 .49376 .56628 40 .83910 .06607 .14198 .27332 .38491 .51164 .58678 41 .86929 .06844 .14709 .28315 .39876 .53005 .60789 42 .90040 .07089 .15218 .29329 .41302 .54902 .62965 43 .93252 .07342 .15778 .30375 .42730 .56861 .65211 44 .96569 .07525 .16338 .31455 .44297 .58884 .67531 45 1.00000 .07881 .16920 .32573 .45871 .60975 .69930 C orrect Feed per one Key solution of Head Spindl 6 = Tan . of Angle Feed Pulley Feed I 'uUey Const Counte r Drum Table 5. — For Finding the Correct Feed per Revolution of Spindle or the Diameter of Feed Pulley, for any given Cam Angle. No. 1 Machine. PRATT & WHITNEY CAM AND FEED TABLES 31 P. & W. No. 2 Automatic T.\NGEN'I^OF ANGLE FEED PULLEY CONSTANT Tangent R.ATIOS u 24:1 11.10:1 5.8:1 4:1 3:1 2.6:1 X Feed Feed Feed Feed Feed Feed Q Pulley Pulley Pulley Pulley Pulley Pulley Const. Const. Const. Const. Const. Const. 10.9 7.86 4.08 2.81 2.11 1.83 1 .01746 .(X)103 .0022 .0042 .0061 .0081 .0093 1.V .02019 .00154 .0033 .0064 .0093 .0123 .0142 2 .03492 .00206 .0044 .0086 .0125 .0166 .0191 2* .04366 .00257 .0055 .0105 .0153 .0204 .0234 3 .05241 .00310 .0066 .0127 .0185 .0246 .0283 4 .06993 .00413 .0089 .0172 .0249 .0332 .0382 5 .08749 .00517 .0110 .0213 .0310 .0412 .0474 6 .10510 .00621 .0133 .0257 .0374 .0500 .0572 7 .12278 .00726 .0156 .0301 .0438 .0583 .007(J 8 .14054 .00831 .0178 .0343 .0498 .0664 .07(53 9 .15838 .00937 .0201 .0387 .0562 .0749 .0801 10 .17633 .01043 .0224 .0431 .0627 .0834 .0959 11 .19438 .01150 .0246 .0475 .0691 .0913 .1057 12 .21256 .01257 .0269 .0519 .0755 .1005 .1155 13 .23087 .01366 .0293 .0506 .0822 .1095 .12.59 14 .24933 .01475 .0316 .0010 .0886 .1180 .1357 15 .26795 .01585 .0340 .0657 .0954 .1270 .1461 16 .28675 .01696 .0364 .0703 .1022 .1.360 .1.504 17 .30573 .01809 .0389 .0750 .1089 .1450 .lOOS 18 .32492 .01922 .0413 .0796 .1157 .1541 .1771 19 .34433 .02037 .0437 .0843 .1225 .1031 .1875 20 .36397 .02153 .0462 .0892 .1296 .1725 .1984 21 .38386 .02271 .0488 .0941 .1367 .1820 .2093 22 .40403 .02390 .0513 .0990 .1438 .1915 .2202 23 .42447 .02511 .0538 .1039 .1509 .2010 .2311 24 .44523 .02693 .0565 .1090 .1584 .2109 .2425 25 .46631 .02759 .0592 .1142 .1659 .2209 .2540 26 .48773 .02885 .0620 .1197 .1737 .2313 .2000 27 .50953 .03014 .0646 .1247 .1812 .2413 .2774 28 .53171 .03146 .0676 .1303 .1894 .2522 .2899 29 .55431 .03279 .0704 .1357 .1972 .2626 .3019 30 .57735 .03416 .0733 .1414 .2054 .2735 .3145 31 .60086 .03555 .0763 . .1472 .2140 .2849 .3275 32 .62487 .03697 .0794 .1531 .2235 .2963 .3400 33 .64941 .03842 .0824 .1590 .2310 .3076 .3537 34 .67451 .03991 .0856 .1651 .2399 .3195 .3073 35 .70021 .04143 .0889 .1715 .2492 .3318 .3815 36 .72654 .04299 .0922 .1779 .2585 .3431 .3957 37 .75355 .04458 .0956 .1845 .2681 .3569 .4104 38 .78129 .04623 .0992 .1913 .2780 .3702 .425() 39 .80978 .04791 .1029 .1985 .2882 .3839 .4415 40 .83910 .04965 .1066 .2056 .2987 .3977 .4573 41 .86929 .0514 .1104 .2129 .3094 .4119 .4770 42 .90040 .0533 .1143 .2205 .3204 .4266 .4905 43 .93252 .0552 .1184 .2283 .3318 .4418 .5079 44 .96569 .0572 .1226 .2364 .3435 .4574 .5259 45 1.00000 .0592 .1272 .2450 .3560 .4740 .5450 Correct Feed per one Revolution of Head Spindle Tan of .\nsle Feed Pulley Feed Pulley Const. Counter Drum T.\.BLE 6. For Finding the Correct Feed per Revolution of Spindle or the Diameter of Feed Pulley, for any given Cam Angle. No. 2 Machine. 32 CAMMING THE PRATT & WHITNEY AUTOMATIC SCREW MACHINES P. & \ V. No. 3 )MATIC TANGENT OF ANGLE AUTC FEED PULLEY CONSTANT (open belt) I Tangent R.\TIOS H 58:1 21.9:1 10.1:1 8.19:1 5.7:1 4.2:1 a, o Feed Feed Feed Feed Feed Feed w Pullev Pulley Pulley Pulley Pulley Pulley O Const. Const. Const. Const. Const . Const. 32.9 12.4 9.1.3 4.65 3.23 2..38 1 .01746 .00053 .00137 .00186 .00365 .00526 .00714 1* .02619 .00079 .00209 .00285 .00559 .00805 .01092 2" .03492 .00106 .00282 .00383 .00752 .01083 .01470 2* .04366 .00132 .00346 .00471 .00924 .01331 .01806 3" .05241 .00159 .00419 .00569 .01118 .01610 .02184 4 .06993 .00212 .00564 .00766 .01505 .02167 .02940 5 .08749 .00265 .00701 .00953 .01870 .02693 .03654 6 .10510 .00319 .00846 .01149 .02257 .03250 .04410 7 .12278 .00373 .00991 .01347 .02644 .03808 .05166 8 .14054 .00427 .01128 .01533 .03010 .04334 .05880 9 .15838 .00481 .01273 .01730 .03397 .04891 .06636 10 .17633 .00535 .01418 .01927 .03784 .05448 .07392 11 .19438 .00590 .01564 .02124 .04171 .06006 .08148 12 .21256 .00646 .01709 .02321 .04558 .06563 .08904 13 .23087 .00701 .01862 .02529 .04966 .07151 .09702 14 .24933 .00757 .02007 .02726 .05353 .07709 .10458 15 .26795 .00814 .02160 .02934 .05762 .08297 .11256 16 .28675 .00871 .02313 .03142 .06170 .08885 .12054 17 .30573 .00929 .02466 .03351 .06579 .09473 .12852 18 .32492 .00987 .02619 .03558 .06987 .10062 .13650 19 .34433 .01046 .02773 .03767 .07396 .10650 .14448 20 .36397 .01106 .02934 .03986 .07826 .11299 .15288 21 .38386 .01166 .03095 .04205 .08256 .11888 .16128 22 .40403 .01228 .03256 .04424 .08686 .12507 .16968 23 .42447 .01290 .03417 .04643 .09116 .13127 .17808 24 .44523 .01353 .03587 .04873 .09567 .13777 .18690 25 .46631 .01414 .03756 .05103 .10019 .14427 .19572 26 .48773 .01482 .03933 .05344 .10492 .15108 .20496 27 .50953 .01548 .04102 .05573 .10943 .15758 .21378 28 .53171 .01616 .04288 .05825 .11438 .16470 .22344 29 .55431 .01684 .04465 .06066 .11911 .17151 .23268 30 .57735 .01754 .04651 .06318 .12405 .17864 .24234 31 .60086 .01826 .04844 .06581 .12921 .18607 .25242 32 .62487 .01896 .05037 .06844 .13437 .19350 .26250 33 .64941 .01973 .05231 .07106 .13953 .20093 .27258 34 .67451 .02050 .05432 .07380 .14491 .20867 .28308 35 .70021 .02127 .05642 .07665 .15050 .21672 .29400 36 .72654 .02208 .05852 .07949 .15609 .22477 .30492 37 .75355 .02290 .06069 .08245 .16189 .23312 .31626 38 .78129 .02374 .06295 .08552 .16791 .24179 .32802 39 .80978 .02461 .06529 .08869 .17415 .25077 .34020 40 .83910 .02550 .06762 .09187 .18038 .25975 .35238 41 .86929 .02642 .07004 .09515 .18683 .26804 .36498 42 .90040 .02736 .07254 .09855 .19350 .27864 .37800 43 .93252 .02833 .07512 .10205 .20038 .28854 .39144 44 .96569 .02934 .07778 .10566 .20747 .29876 .40530 45 1.00000 .03040 .08060 .10950 .21500 .30960 .42000 C( jrrect Feed Tan per one Re"' of Angle t^olution of '. ^^ Feed iead Spindl Pulley 6 = Feed Pulley Const. Counter Drum Table 7. — For Finding the Correct Feed per Revolution of Spindle or the Diameter of Feed Pulley, for any given Cam Angle. No. 3 Machine. PRATT & WHITNEY CAM AND FEED TABLES 3.3 5 si O 2 £ i > J g O a 5 s < o !M re It o 1^ X o ei T t^ r: re -r o ~. — -r o o o re o O u: o (M O O -T X Ti 1- ^ >-e c; re X ei t^ '-e 't -r -r — -T -r -r -.;; l^ ^3 •-1 .— oi ei ei re re -r -T -T i-e It -.c o t>- X ~ O O " 01 re T 't '-O 00000 000000000000.^-.-H^-H^ — _ OOOOOOOOOOOOOOOOOOOOOOOOO ^ 00098 00131 001(54 00197 00230 002(53 002!)6 00.330 003(53 00.3!)7 00432 0046(5 00.501 005.36 00608 00(581 0075(5 00832 00872 00!) 12 00!)! 1 4 01080 01168 01261 01309 3" .00073 .00098 .00123 .00147 .00172 .00197 .00222 .00247 .00273 .002!)8 .00323 .00350 .00376 .00402 .00456 .00511 .00567 .00624 .00654 .00(584 .00746 .00810 .0087(5 .00946 .00982 l-Q 00049 000(55 00082 00098 00115 00131 00148 00165 00182 00199 00216 00233 00251 00268 00304 00340 00378 00416 0043(5 00456 00497 00540 00584 00631 00655 0! CO z § s o « li to Id ai ^ O Q Ui z to 2 s PL, a lu O a: S < a 2:5 ce — < s; r>- It re 'M -^ o c: c. o O ei CO c-i oi -t --^ O o -f -r o C5 ■^orexrexrexret^eixrexxoo — t^re'ti^oreo ^ ^ "M 01 re re -p ^ It 't --2 -t t-- r- X c; — ei ei re -r It t^ X o oooooooooooooooo^ — — — — ^^^r^ ooooooooooooooooooooooooo ^ 00114 00153 00191 00229 00268 00307 00.346 00385 00424 004(54 00504 00544 00584 00(52(5 0070!) 007!)4 008S2 ()0!)71 01017 01064 011(50 012(50 013(53 01472 01528 CO 00086 00114 00143 00172 00201 00230 0025!) 00288 00318 00348 00378 00408 00438 004(5!) 00532 0()5!)5 00(5(51 00728 007(53 007!)$ 00870 00!)45 01022 01104 01146 1 1^ 00057 00076 000!)5 00115 00134 001.53 00173 001!)2 00212 00232 002.52 00272 00292 00313 00354 00397 00441 0048(5 0050!) 00532 00580 00(530 00(582 00736 007(54 1 For 9* Counter Drum. Spindle Speeds 905-064-540. .J 5 PL, a u O Di U H W a < is .00191 .00254 .00318 .00382 .0044(5 .00511 .0057(5 .00(541 .00707 .00773 .0083!) .0()!)0(5 .()0!)74 .01042 .01181 .01.323 .014(59 01618 .01(595 .01773 .01!).33 .0209!) .02272 .024.52 .02546 ^ 0-1 re -f o r>- 35 — ' re o X 01 It o -^ It C5 It Lt cc o t^ o X 01 r- i-t O It o It O o -H -^ « i^ -M X re -r It i^ o it — i -r X — o re ^ oi oi re re ^ ^ It ^ j3 --3 h; r; X r5 o — oi re -t< It o X o o q q q q q c q q q q 5 q q q q q q q q q q q q q q lo 00114 001.53 00191 00229 00268 00307 00346 00385 00424 00464 00.504 00544 00585 00625 00709 00794 00881 00971 01017 01064 011(50 012(50 013(53 01471 01528 1 !-« .00076 .00102 .00127 .001.53 .00 179 .00204 .00230 .00256 .00283 .003,)i) .0033(5 .003(53 .0().3!)() .00417 .00473 .00.529 .00588 .()();547 .00(578 .00709 .00773 .00840 .00909 .00981 .01018 1 a < b Id o g Id Id < re'^i00t>-xoo — oiro'»<>oi£>XO(N'*»-tcoxooj'C 1 -^ — •-:: — '^ 7 1 1^ TT -T lC t^ CO uC -^ ■^ I~^ -H lO -M r-H (M 01 rc rc ^ -T 1': i-r :£ '-r ij; i_^ X r: ^ :~i r? ^ ic c^ (X c: ooSS3S3o355535ooooocooooo £3 C032-H^OCi'MCOC73Ccr^!MCDC^^OOL'^'^LOI>CCCCOCOOO 0003w_;00OC;»^C:0C:0000000O00 ^ ^ lO 02 ^ r^ — < '-0 c-1 1^ -r t^ rc c 3 fM r^ ^ to oi c^i OMcoorot^O-ri^^-rcc— ^i':'MC;x-^c:-fc-ioooio ^ ^ — . ^1 c) C-) ^? ro -r -r rn T >c irt ;r i^ 1^ X — cr. ^ oi CO ro OOOOC:0C:0C;3C0 0C;0C:C;C:C:O'-H-H— <^T^ ocoooooooooo 000 C' 000000000 CO ^ --H t^ oi x -r a: ^ X -r rt 00 ic t^ 'C i-t i-t :r lc r^ -^ t- M Lt t^ T 1 '^ GO re --C X — 1^ ^1 X -r t- t- r-r t- -H ^ rf ^ -- 2J 2J -J L! 12 11 •-• i2 ^ ^ 12 'J- '::£ -S Ir Ir i2 S S ^ o g;? o » =^ Si S S3 Z m » Q O w U w CM ?,. ^ o « fa 2 p< in >< w J J a Oh Q W fa f» o 5 H W S < 5 cO'Hr3200:ci-o-*-t01^t^OrCl^^^ 0> IM CO 000000 000000^-^-H,^^rt^,-i CI OlC^l 0000000 00 000 ooO' 0000000000 5; "-'^ CO — i ~. X r^ _: "O -J^ r^ r^ c: — < -t '^ X CO 10 CI CO r^ -r ~ T ~ CO X C- X CO X CO X CO — =^ -H 01 X 'T O) CO CO ^ Z; iJ ZJ 12 IS !2' !I '-2 'i: ':i ':S I:: t ^ ^ "^ ^' "-^^ ^ '*' ^'^ '~^ '^ '-'^ 0000000000000000000000000 co-rcooi'^oocso50200^cor>"Cooicoococc'^a5Xio —iiOClCOt^— iioxoico— iiOOCO— iOCJ:X01t^l>l>t^00Tj< ^— irtOlOlCOCOCO-^-i^iOiOiCCOt^XXCC^OO^ClCO-^LO 0000 00000 000000 OOC'^-H-H^,-H,-^^ 0000000000000000000000000 CO t^ LO -f CO CO '^1 "^l 01 CI f^t CI CO "0 X -^1 ~- r^ ^1 t^ lO rf CO CO ^ TT t^ CO 01 to X ^ -r (^ CO --o CO 1^ x i-o co --^ lo — t ^ — H CI CI CI CJ CO CO CO -r -r- -t 1 -c CO i^ t^ X X 0: ^ ^ COOOOOOOOOOOOOO'OO— 'OO'OO^-Hrt 0000000000000000000000000 w =^ a ^ P 1 «^ ° 1 « -J O fa g C/3 w I-] o fa Q w H fa O « w H H IS < cior-co-rco^— ^^r-iocoioxiocooo-^cocoocoi-o-* 1^ CO 1^ -* '— X i-o ci oi CO LO CI X >c CO -< CI ci CO '^ -r 'O CO CO t^ X X m — 1 ci ^ t^ X X 'Tf CO t^ 000000000000— <^^r-i^---^r- CI 00 ClCl 0000000000000000000000000 O Q "^ £5 Cl X lO C) t-- iC m CO CI Cl CO iQ 1— 1 O' CO -— 1 X -H CO cocixcooLooocix-tococi-rt^ocooco^Lo^t^io r-H CI CO CO "* 'O i-o CO CO t^ X X ^H CO -r Lo 1:^ X ^H ci OOOOOOOOOOOOOO—i— i-H— 1^— .^^ctcici 0000000000000000000000000 1 § ^ LOOiC-HCOciX-rOt^-t^CIOXOt^OCOOCOOiCOOCOCO CO X CI t^ ^ CO 10 O' -r ~ -T — . CO CO CO -t- -r LO CO X CO ^ -H CI M CO " ^ — • - 1 ' cr -o 1 ~ X r: — 1 c 1 CI CO ^ CO i> X 0000000000 — 00000-^— I'-H^-H-H-^—l-H 0000000000000000000000000 CO ^lOocor-^-Hcooi-ooco-Ht^-^t^coooocii^Lor-cicj OcocOOCOt^O-^t^— i^X^LOClOXCOO^CI— lOOiO ^H^Hi — ^cicicicococo'^'^'^i-oi^cor^r^xcT^oOi — ^^icoco 00000000000000000000----— l-HrH 0000000000000000000000000 CO ^ 05 g CO «c^ '^ W « J O Q fa Z C/3 w ►J a fa w w fa o « H < -H lO CO I^ CI t-- CO 'O CO — X '^ CI CO t 10 CI CI 01 CI -t< -H -0 — — — t^ >-0 CI CO r^ CO '0 -r CO co -r -fi ci CI CO -^ 'O 10 CO i^ yi' X 35 -H ci CO ic t^ X 01 -T co x 00000000000— lr-H,-H—(r^-H--l--ClCIOIOI CI Cl 'J'LOt^OS— icocoocicooicocooxxcot^cioi>coxx X'*iOcOC003iC-HX^-Ht>--*0-^t^-HOCO— lOClOCOiO ^ClC0C0-f^i-0'C0C0l:^XXOO-HCl^i0C0l>-XO^C0'*i 0000000000000 — —l-H—<^-H-H—( CI CICICI Pi Tfl l> CO CO "O 10 10 '0 10 CO t^ X CI 10 CI CI 'O CO CI to -^ CO -r -r ~. -t- -T -T — — C: 1 — CI CO lO) -^ t~^ CI i-C CO -^ — cioicoco-t; — ijoijTcor^r^XoO— 'Cicocorrcot^XOi 0000000000000000000000000 ?o OI>rti-H02CO'rrr^C:XcOLO'^Tf^tv.— HXCir^OCOCO-^iO T-HTfxciLcocot^OTrxcicooxo"'ocoxcici— i-HCit^ ^ ^ ^ CI CI CI CO CO -* ^ ■* lo i-o CO CO r- X a> — CI CO Tt< Tfi 000000 O' 000000000000— l—"-^ — —l-H 0000000000000000000000000 c < g 3p COrt.XCRO^ClCO-*'OCOXOClrfHiOCOXO(MTf-ICldClCl(MCSC0COCOC0 PRATT ct WHITNEY CAM AND FEED TABLES 35 z fa «: O u o o > < ^ d W Q fa < o ? 5^ =a a 7 G •» H « 5 a o u cj w • ^ w fa 5 0. Q T o a |s u. S 1-1 ^ Tlt^ '^. 'c -r -f -r ^ T -^ _ -r X -r ^ -v* ej 00 »— < 'C ^ CI ^ O -r X Ti -^c O-r X ?i ^ T. X r~ ^ 1^ ;f, t>- ot t 1— « .— . .— 1 1^1 '^1 T'' T^ re T -r i.e 'C iC ^ t^ t^ / -^ •"-. r^ P— I r^l --^ -p 1-1 o ^^ O O <— '' '^ O o OO O O ^ ^ ^ C"*^ •— t •— 1 1-^ ^^ ^i oq o q —i ^ ^/^/■^_z^_ ^ R R R q ^ qqqq qqq >c r^ ~ -H -v 1* y „ ,^ .^ ^. -/- t- — _ -i- _ X ._ .-* * -^ to c: -M 'O r: '^ 1 1 '7 ri 'e cc vi '-'".- X ei .T. 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UJ Z UJ < 1- z 1- _J > uJ CC u. cc UJ m Z 63 74 86 lOI 119 139:1631191 224 262 307 360 10 3600 3200 40 40 5 70 S2 96 112 '32 1541181 212J249 291 341 400 II 3272 2900 40:44 5 77 90 106 124 145 169 199 233 274 320 375 440 12 3000 2700 40 43 5 84 9S 115 135 15S •85 217 255 298 350 410 4S0 13 2769 2400 40 52 4 91 107 125 146 172 201 236 276 323 379 440 520 14 2571 2300 30 42 4 9S "5 134 •57 .85 216 254 297 348 408 47S 560 15 2400 2100 40 60 4 105 1-3 144 169 19S '^ ■> -j- 272 318 373 437 512 600 i6 2250 2000 30 48 4 112 '31 ■54 180 211 247 290 339 398 466 546 640 17 2117 1900 20 34 3 119 139I163 191 224 263 308 361 423 495 5S0 680 i8 2QOO iSoo 30 54 3 126 148 173 202 23S 278 326 382 44S 524 614 720 19 1894 1700 20 38 3 ^33 156 .82 214 251 294 344 403 472 554 649 760 20 1800 1600 20 40 3 140 164 192 225 264 309 362 424 497 5S3 683 Soo 21 I7I4 1500 20 42 3 147 172 202 236 -11 324 380 446 522 612 717 S40 22 1636 1450 20 44 3 154 I So 211 247 290 340 399 467 547 64. 751 880 23 1565 1400 20 46 3 161 1S9 221 259 304I355 4"' 7 488 572 670 7S5 920 24 1500 1350 20 48 3 160 197 230 270 317I371 435 509 597 699 819 960 25 1440 IjOO 20 50 3 •75 -05 240 2S1 330 386 453 530 622 728 S53 1000 26 1384 1250 20 52 3 182 -'3 250 292 343 402 471 552 647 757 8S7 1040 27 1333 1200 20 54 3 1 89 221 259 304 356 417 489 573 671 7S7 922 loSo 28 1285 II50 2a 56 3 196 230 269 315 370 433 507 594 696 S16 956 II2C 29 1241 1100 20 58 3 203 ^-3^ 27S 326 383 44S 525 615 721 S45 9901 1 6c| 30 1200 1050 20 60 3 210 246 288 337 396 463 1 543 636 746 S74J1024J1200 1 The number of hundredths given is always sufficient for usually best to add 1-JOO for revolving the Table 12. — For Laying Out Cams for Brown A: Shari>e Machine. feeding Turret. stock, but it is No. OU Automatic Screw 62 LAYING OUT BROWN & SHARPE SCREW MACHINE CAMS No. AUTOMATIC SCREW MACHINE Table for Laying- Out Cams. Ill coo QLU ?^ 1- 3 q: 00 ^S 0? 3 Oil X '- •^ en — z &i Q (/) q: q: l- UJ z t < X w z > a z 0: < 1- Ll. < X w s d: Z < tOLLl X^ ^^ to Q UJ LU CL w ID _l Q Z (^ w «T- _jir-i nr n ' SPINDLE SPEEDS I 1st SH. 1 l| -L -[ BELl t TOMACJ4INEON | n u ^ --' B i A 2N0 SH. 1 i B 1 FAST u-i 10 CO 2 00 -5 D ^ ^ u J SLOW M 2 ri CO ON ri ^ -1- CO t ^2 \0 CO CI ri ^ C\ C7\ d rp d ^ 4 VO ^ t^ C\ » 6 CI Lp ro i -1- 00 CI 10 re -i- c2 M CO 5 7200 6400 120 20 14 UJ U Q. UJ Z Ul < H co z {- _l > Ul oc u. cc UJ Z3 Z 17 20 2S 30 37 45 55 67 82 101 123 150 6 6000 S400 120 24 12 20 "3 24 28 36 44 54 66 81 99 121 147 180 7 SI42 4600 120 28 10 55 42 52 63 77 94 "5 141 172 210 8 4S00 4000 120 3- 9 27 33 40 49 59 72 88 loS 132 161 ■97 240 9 4000 3600 120 36 8 30 17 4S 5S 67 Si 99 121 148 181 221 270 10 3600 3200 120 40 7 33 37 41 4.S so 61 74 90 no MS 16s 201 246 300 II 3272 2900 120 44 7 ss 67 82 100 122 148 181 221 270 330 12 3000 2700 60 -4 6 40 49 60 73 89 109 ^33 162 198 241 295 360 1,1 276q 2400 120 s:^ 6 43 51 6S 79 96 118 144 17s 214 262 319 390 14 2S7I 2300 60 28 ,s 47 .S7 70 8s 104 127 155 189 231 282 344 420 IS 2400 2100 60 30 ,s 50 61 74 91 II I 136 166 202 247 302 368 450 i6 "SO 2000 60 3- ,s .S3 6S 79 97 119 145 177 216 263 322 393 480 I? 2117 1900 60 34 4 .S7 69 c H >9 103 126 154 188 229 280 342 418 510 i8 2000 iSoo 60 16 4 60 73 1 109 r^3 163 199 243 296 362 442 540 19 1894 1700 60 3S 4 63 77 94 ii,S 141 172 210 256 3^3 382 467 570 20 1800 1600 60 40 4 67 81 99 121 148 181 221 270 329 402 491 600 22 1636 I4SO 60 44 73 89 109 1.11 163 199 243 297 362 443 540 660 24 1500 I ISO 40 32 3 80 98 ri9 146 178 217 26,s 324 395 483 590 720 26 1,184 1250 60 5^ 3 87 106 129 iss 193 235 287 351 428 523 (539 780 28 128s 1 1 50 60 S6 ,1 93 114 139 170 208 253 309 378 461 563 688 840 10 1200 1050 60 60 3 100 122 149 182 222 271 33^ 405 494 603 737 900 32 1125 1000 30 32 3 107 130 159 194 237 290 3S4 432 527 644 786 960 ,14 I0S9 9, SO 30 34 3 113 118 169 206 2S2 308 376 459 560 684 835 1020 16 1000 900 30 36 3 120 146 179 218 267 326 398 4S6 593 724 884 1080 38 947 850 30 3S 3 127 i.SS 189 231 282 344 420 5M 626 764 934 II4O 40 900 800 30 40 3 133 163 199 243 297 3^2 442 540 (559 805 983 1200 44 81S 72s 30 44 3 147 179 218 267 326 398 486 594 725 885 1081 1320 48 7 SO 67 s 20 32 ■^ 160 19.S 238 291 3.S6 434 530 648 790 966 1179 1440 S- 692 620 30 S2 1 171 21 1 2SS 31s 38 s 471 S7S 702 8s6 1046 1277 1560 S6 642 S7S 30 S6 3 1S7 22S 278 140 415 507 619 756 922 1127 137b 1680 60 600 S2S 30 60 3 200 244 29S 164 445 543 663 810 988 1207 ■474 1800 65 S.S.I 490 30 6s 3 217 264 323 394 482 588 718 877 1070 1308 1597 1950 70 SI4 4S0 24 S6 3 •^33 2Ss ns 424 S19 633 773 945 1 1 S3 1408 1720 2100 7S 4S0 410 24 60 .1 2 so 10 s 172 4.S,S SS6 O79 829 1012 123=; 1509 1842 2250 80 4 so 400 30 80 ,1 267 325 397 485 593 / -4 8S4 1080 1317 1609 19(35 2400 90 400 3 SO 20 60 ^ 300 366 447 S46 667 814 994 121s 1482 1810 2211 2700 100 360 300 24 80 3 333 367 407 447 497 607 742 905^1105 1350 1647 2012 24S7 3OQO 110 327 290 30 no 3 S46 667 816 995 1215 1485 1811 2213 2702 3300 120 300 270 20 80 3 400 488 596 728 SgolioSe 1326 1620 1976 2414 2948 3600 Table 13. For Laying Out Cams for Brown & Sharpe No. Automatic Screw Machine. BROWN & SHARPE CAM TABLES 63 No. 2 AUTOMATIC SCREW MACHINE. Table for Laying Out Cams. UJ (rtO QUJ Olil t-o trt 1- < X I/) 2 > Q 2 DC < UJ 1- ^n 2 < Hi C5 Q Z3 1- (/) 2 a: < UJ ■0 c S q: 2 cc < UJ UJ < Li. tc 03 . SO 0^ C/)liJ XUJ l-u- Qq Z X (/) a ill UJ a. in UJ _i Q Z CL 'fi > UJ _l _J Q- 3 43 Ri ..M.I h R.P.U_ .p, SPINDLE SPEEDS li D. to — X 2° 22 ^^ i/> a. 1- LJ Z 1ST — l 1 --- II BELT TO MACHINE ON SMAfI' 1 1 PULLEY ii _A r C Jl A 2^ SH nf" -n FAST c, CI — "T C| CO 1- CO CO CI 41] kfT - SLOW CI CI CI CO CI 10 6 UJ M 06 d 1^ CI z 2 CO CI CO CI r- CI CI CI -1- c-1 r, as 10 rl- CO 1^ CO C\ CI 6 6000 5400 So 32 80 40 17 12 15 18 22 2 8 34 42 52 64 79 97 120 7 5142 4600 80 32 72 42 15 14 17 21 26 3 2 40 49 6x 75 92 114 140 8 4500 4000 80 32 72 48 13 16 20 24 30 3 7 46 56 69 85 105 118 13c 146 160 180 9 4000 3600 80 32 72 54 12 iS 22 27 34 4 2 51 63 7« 96 lO 3600 3200 80 32 72 60 10 20 25 30 37 4 6 57 70 86 107 131 162 200 II 3272 2900 80 32 84 77 10 *> "» 27 33 41 5 I 63 77 95 117 145 178 220 12 3000 2700 80 32 60 60 9 111 a. UJ z u < CO z H _l > LU CC u. cc ai ca :d z 24 30 36 45 5 5 68 84 104 128 158 195 240 13 2769 2400 80 32 72 78 9 26 32 39 49 6 74 91 112 139 171 211 260 M 2571 2300 So 32 60 70 8 2S 35 42 52 6 5 So 98 121 149 184 227 280 i6 2250 2000 So 32 60 80 7 32 39 49 60 7 4 91 112 138 171 210 259 320 i8 2COO iSoo 80 32 43 72 6 36 44 55 67 8 4 103 126 156 192 237 292 360 20 1800 1600 So 32 48 80 5 40 49 61 75 9 2 114 140 173 213 263 324 400 22 1636 1450 80 32 42 77 5 44 54 67 82 IC 2 125 154 190 235 289 357 440 24 1500 1350 80 32 40 80 5 4SI 59 73 90 II I 137 16S 208 256 316 389 480 26 1384 1250 80 32 36 78 4 5= 64 79 97ii^ 14S 1S2 225 277 342 422 520 28 I2S5 ^50 80 32 36 S4 4 56 69 85 I05J12 9 160 196 242 299 368 454 560 ao 1200 1050 60 60 So 80 4 60 74 91 11213 8 T71 210 259 320 394 4S6 600 35 1028 925 60 60 72 84 3 70 87I106 .3.!ie 2 199 246 303 373 460 568 700 40 900 800 60 60 54 72 3 8oj 99121I150J1S 5 228 281 346 427 526 649 800 45 800 700 60 60 48 72 3 90|i 1 1 136J1692C S 256 316 389 480 592 730 900 50 720 625 60 60 48 80 3 loo'i: IIOI^ 4 15218723 I 285 351 432 533 657 811 1000 55 654 575 60 60 42 77 3 6i67|2o6;2 5 4 313 386 476 587I 723 892 1100 60 600 525 40 80 60 60 3 I20 14bilS2?25!27 7 342 421 519 640 7S9 973 1200 70 514 450 40 So 60 70 3 l4ojl73'2i2 160198,243 p62'32 3 399 491 605 747 920 11351400 80 450 400 40 So 54 72 3 300,3c 9 456 56. 692 S53 1052 1297,1600 90 400 350 40 So 48 72 3 i8o|222273^374i 5 513 631 778 960 1183 1459J1800 100 360 300 40 80 48 80 3 200,2471033754c 2 570 702 861 1067 1315 1622 2000 110 327 290 40 So 42 77 3 2201272334^12 5c )8 627 772 951 1173I1446I17S4 2200 120 300 270 40 So 40 So 3 2401296 364'^! 50 55 4 684 842 103S12S0 157SI1946 2400 135 266 240 36 72 40 90 3 2 70J33409;5<^^(^; 3 769 947Jii68ii440,i775 2iS9 2700 150 240 210 36 80 40 90 3 300i370 4 55'562J6c )2 855 i052;i297;i6oo!i972 2432 3000 I6S 218 190 36 77 35 90 3 33o!407 50o^icJ7c 2 9401158 i427li76o;2i70 2675 3300 180 200 180 36 34 35 90 3 360^144 546,67^8311102^1263 15571192012367,2919 3600 Table 14. — For Laying Out Cams for Brown «S: ^harpc No. 2 Automatic Screw Machine. CHAPTER V The Brown & Sharpe Automatic Screw Machine with Constant- Speed Drive The Brown & Sharpe, No. 2 G, automatic as equipped with constant- speed (h-ive is illustrated in Figs. 42, 43, and 44. The general form of Fig. 42. — Brown ' is connected by a friction clutch. Hy means of this friction clutch the machine is started or stopped, and there is. in addition, indepemlent means provided for starting and stopping the feed when desired. The slitling gear B through gear C drives back shaft D, which in turn drives the clutch shaft G through the change gears E and F. Keyed to the shaft G is the friction body with faces H and /, and mounted loosely 66 THP: brown & SHARPE AUTOMATIC SCREW MACHINE on shaft G is the gear ./ on one side of the friction body, and on the other side of the body the gear K and chain sprocket L, both of which are fastened to the friction back M. Mounted loosely on shaft D is a quill on which are the gears and B and the sprocket P^. When the clutch face / engages the friction back M, the spindle is driven back at a slow speed through the sprocket L and the chain and sprocket A^ and the spindle is driven forward at a slow speed through gears K and 0, the sprocket P, and chain and sprocket Q. When the clutch face H engages the gear J the spindle is driven forward at a fast speed through gear B, the sprocket P, and the chain and sprocket Q, and is driven backward at a fast speed through gears R, 0, and K, the sprocket L and chain and sprocket A^. Fig. 44. — Details of Clutch The direction of the spindle rotation depends upon whether the clutch body on the spindle is engaged with sprocket A^ or sprocket Q, both of which are loose on the spindle and are provided with roller bearings. All bearings in the driving mechanism are bushed with bronze and oiled from pockets on the outside of the case. The friction clutch in the machine driving pulley is of novel design. The driving pulley A carries a split friction ring T and T^, which is ex- panded by the two hardened rolls S and *S^ on the end of the sliding gear B. These rolls operate against the hardened shoes U and U^, the inner surfaces of which are arcs of circles. The sliding gear B is operated by a conveniently located hand lever. To operate the friction, the rolls are forced in between the shoes a little beyond the centers of the arcs, thus expanding the ring and clamp- ing it to the pulley. As the rolls are beyond the centers of the arcs, they remain locked in position. To compensate for wear, the friction ring is adjusted by the screw IF, and clamped by the set screw X. CHAPTER VI The Cleveland Automatic Turret Machine axd its Cam Adjust.mexts One of the types of turret machines made by the Cleveland Auto- matic Machine Company, Cleveland, Ohio, is illustrated in Figs. 45, 46, and 47. The latter is in reality a plan view of a different size of machine than that shown in Figs. 45 and 46, but the construction is essentially the same. lici. 4.'). — C'lc'VLland Automatic Turret Machine SPINDLE DRIVE On the Cleveland machines, except in the cases of those built for light forming and brass work, which are direct driven, the spindle is driven 67 68 THE CLEVELAND AUTOMATIC TURRET MACHINE by gears arranged on the shaft parallel to and behind it, so that a single belt running continuously in one direction will, when shifted from one Fig. 46. — Cleveland Automatic Turret Machine (Rear View) Fig. 47. — Cleveland Automatic Turret Machine (Plan \'ie\v) pulley to another, drive the spindle alternately in opposite directions, as is recjuired in threading a screw and backing off the die. These gears ARRANGEMENT OF CAMS 69 are usually so proportioned that the speed of the spindle is greater when running in one direction than the other, so that in threading the die may be run off the screw at a much higher speed than is used in cutting the thread. Other operations, including cutting off, may also be run at the higher rate of speed. The movement for reversing the spindle when threading is practically an instantaneous one and the full width of the belt is used until the operation of threading is completed. The spindle carries the usual type of spring chuck and feed tube for the bar stock. TURRET AND CROSS SLIDE The turret for carrying the tools is mounted on a horizontal shaft located parallel to the spindle. The tools are held in a concentric posi- tion in the front end of the turret and tiie latter is indexed and locked at its periphery on a radius larger than that of the circle in which the tools are disposed, thus serving to maintain proper alinement of the tools with the work spindle. The means of supporting the turret during its forward and backward movements in the head, and the location of the longitudinal indexing notches in its periphery, are shown clearly, as is also the arrangement of the cross slide which ordinarily carries two tool posts, one or both of which may be usetl as operations require. GENERAL SYSTEM OF OPERATION* The mechanism for operating the turret and the cross slide, as well as the stock feed and chuck, is driven through speed-changing friction disks, b}' a quarter-turn belt from the countershaft which drives the work spindle. This feed-driving mechanism, by means of planetary gears and suitable clutch connections, provides an automatically controlled rapid traverse for the turret and cross slide during the non-cutting move- ments and a slow, readily regulated rate of travel during the actual cutting operations. The method of controlling this feed di-ive will be referred to later. It will be understood, of course, that turret and cross slide, feed mechanism, etc., may be conveniently operated by hand by means of crank handle and lever, when setting up for a given piece of work. An inspection of the half-tone engravings and the line drawing. Fig. 48, will reveal the location and character of the various cams, the means of controlling the spindle-driving belts, and other features of impor- tance. ARRANGEMENT OF CAMS The cams may be classed under the following names: Turret cams, feed-regulating cams, cross-slide cams, chuck opening and closing cams, stock-feed cams. These cams are all clearly shown in position, in the half-tone engravings, and are represented also in the drawing. Fig. 48, which is a plan view of the operating mechanism. 70 THE CLEVELAND AUTOMATIC TURRET MACHINE The turret cams located just to the rear of the turret, as seen in Figs. 45 and 47, are shown at C and D in the diagram. Fig. 48. These cams are fixed and are never changed. The forward and back movements of the turret E, controlled by these cams, are constant for all kinds of work; the idle travel of the turret, before the tools reach the work, is made at high speed, the cutting feed being tripped in just as the tool Fig. 48. — Camming Diagram, Cleveland Automatic Turret Machine reaches the point at which it is to start cutting. The feed of the turret to every revolution of the spindle is variable to suit the conditions of each individual tool held in the turret. That is, if there are five cutting tools in the turret and each tool requires a different feed from any of the others, each individual rate of feed is obtainable by means of the adjust- able feed-regulating cams. FEED-REGULATING CAMS These cams, as seen in the general views, and at F, Fig. 48, are strips of flat steel I x I inch, and each cam is held in place by two screws. The cams may be moved across the face of the drum G, this movement being provided for by slots milled in the drum, where the screws clamp the cams; also, they may be set at slight angles, taking peculiar staggered positions, as may be seen in the drawing. There are two of the cams for each hole in the turret, and the amount of feed per revolution of spindle is con- trolled by these cams to suit the individual requirements of each tool. In setting these cams the operator watches the cutting tools and adjusts the cams until the tools are removing the desired amount of STOCK-FEED CAM 71 stock per revolution of spindle. A slight change of angle on any of the cams produces a noticeable difference in the turret feed. The cams act through the medium of the levers H , which raise and lower the fiiction roll / between the friction disks and so give the variable feed. The disks are clearly shown in Figs. 46 and 47, as well as in the drawing just referred to. The cams F that are set at an angle, or staggering, as they appear in the drawing, are in most cases intended for carrying the roll from one cam to another; that is, from the cam set back to the one forward, or vice versa. There are, however, occasional cases when a cam may be used at an angle, say in drilling certain holes. Thus the drill can start in with the feed decreasing, or increasing, as it advances. When using a drill that is not an oil feed, the lubricant does not reach the cutting edge as the drill advances; for this reason it may be desirable not to feed the drill so rapidly, and in such instances it is advisable to use the feed-regulating cam set at an angle. CROSS-SLIDE CAMS The drum J , carrying the cross-slide cams, has (as will be noticed in Figs. 46 and 47) a number of rows of tapped holes around the periphery. The cams A and B are standard for all work and are adjustable around the drum. The rate of feed of the cross slide is variable, this also being controlled through the regulation of the cam-shaft speed by the feed- regulating cams F, in combination with the turret feed. If a forming tool is working in conjunction with a drill, the feed is set for the heaviest cut each tool will stand. If a cut-off tool is working either in conjunction with another tool or individually, tlie cams that take care of this tool are adjusted without interfering with other tools in the different operations. CHUCK OPENING AND CLOSING CAMS These cams are shown at K, and are also visible in the half-tone illus- trations. As there shown they are cast solid on the face of a segment for bar work, while for magazine and double-camming work a drum is used. For bar work adjustment is unnecessary, as the cams are cast in the cor- rect position to allow ample time for chucking the longest piece within the capacity of the macliine. STOCK-FEED CAM The stock-feed cam L, which answers for all work except where double feed is required, is cast to the required shape and clamped to the cam shaft. The general f(»i'iii is well illustrated in the rear view. Fig. 46, where the cam is shown just to the left of the cross-slide di-um. Its adjustments are either around the cam shaft or lengthwise upon it. In case double feed is desired, that is, if it is required to feed the stock twice to one revolution of the cam shaft, a drum is put on the shaft in il THE CLEVELAND AUTOMATIC TURRET MACHLXE place of this segment, and two cams, which are cast to the same outline as the segment, are fastened to the drum. THE SETTING-UP FORM Fig. 49 illustrates a printed form that accompanies machines that are tooled and covers all adjustment necessar}^ in doing any class of work. POSITION OF TOOLS AND CAMS ON THE CLEVELAND AUTOMATIC Sample No. Order No Mach.No Position of Tools in Turrent Position of Regulating Cams at R 1 1 ^ Regulating Drum 2 P 2 3 o o o o 4 P 3 5 8 M 1 7 U 8 5 2J P ' 10 6 11 P 12 Position of Cross Slide Cnms' Cross Slide Drum Tools on From of Cross Slide Tools on Back, of Cross Slide Pieces per Honr Extra Tools and Aiiachmenib fievolutlons of Countevshaft psr Afiiintp Size of Flange Pulley Size of Spindle Palley Pins in KegtUaring Drum ontside Pins in Rpgnlnrmg fnif' insirlp Kemarks. Fig. 49. — Setting-up Chart for Cleveland Automatic. (Actual Size 6 X 12 inches) The feed-regulating drum, shown at G, Fig. 48, and the cross-slide drum J are both represented on this sheet, which is designed to simplify the setting up of the machine when changing from one job to another. ATTACHMENTS AND TOOLS 73 SPEEDS, FEEDS, ETC. The countershaft diagram is included in the drawing, Fig. 48, M being a three-step cone belted from the main line; .V the drum from which the spin- dle-operating pulleys are driven; P a pulley for driving the feed mech- anism througli the medium of a quartei'-turn belt i)assing over i)ulley Q. In setting up a job on the machine, the speed at which the spindle must revolve in order to get the peri})heral speed of work best adapted to the tools is the first consideration and is obtained by placing the belt from the line shaft on the most suitable of the three steps of countershaft pulley M, giving a fast, medium, or slow countershaft speed. As the tool feed is variable between widely separated extremes of feed, the changing of the speed of the countershaft does not affect the feed of the tools, as the feed-regulating cams F are adjusted to accommodate the faster or slower speeds of tiie countershaft and produce the desired rate of feed of the cutting tools per revolution of work, ATTACHMENTS AND TOOLS A number of useful attachments are made for this machine and two of these are shown in Figs. 50 and 51. The independent cut-off attach- ment is designed to be used in cases where the forming to be done is too long for one forming tool and without this attaciiment would have to Fig. 50. — Iiidopendcnt Cut-olY Attachmcr.t be partly formed on the automatic machine and finished by a second oper- ation in another machine. Hy using the independent cut-off device two forming tools can be used; one on the fi'ont of the cross slide and one on the rear; the piece being cut off by the attachment whicli is in no way connected with tiie cross .slide, but rests on the hood of the live spindle 74 THE CLEVELAND AUTOMATIC TURRET MACHINE and the cam shaft, and is operated by a cam on the hitter. In this way the piece is completely finished on the automatic machine. THIRD SPIXDLE-SPEED ATTACHMENT Another important device is the third spindle-speed attachment by which a slow spindle speed forward is obtained in addition to the regu- lar forward and reverse speeds. This attachment is of service especially when taking heavy cuts or threading work of large diameter and coarse pitch. With the belt on pulley A, Fig. 51, the normal speed is obtained; with the belt on pulley B and clutch C in operative position, the slow Fig. 51. — Third Spindle-Speed Attachment spindle speed is derived through the medium of the planetary gears. When the belt is on pulley D the rapid reverse speed is secured for back- ing off the die or for cutting off the stock. Clutch C is controlled by cams on clrum E and is engaged with pinion F to hold the pinion fast when the spindle is to be driven at slow speed by operating the belt on pulley B. When the clutch is disengaged, releasing pinion F, B becomes a loose pulley. The magazine attachment is not illustrated here as it is shown in position on a Cleveland machine in Chapter XIV. TURRET TOOLS A few typical turret tools are illustrated in Figs. 52 to 57. The first of these is a roller rest box tool with independently adjustable rolls to TURRET TOOLS 75 accommodate different sizes of stock, and with three turning tools adapted to be adjusted in the manner indicated. The block nearest the inner end of the i)ox tool carries an auxiliary steady rest with a roll at its end which may be applied when the work is reduced to such a small diam- eter that it is liable to sprinsi- away fioni the cutting tool which is shown Fig. Roller Rest Bo.\ Tool opposite the rest in a vertical position. Fig. 53 shows a combination drilling and chamfering tool. Fig. 54 is an adjustable boring tool which may be used w^here it is necessary to secure perfect concentricit}' with the exterior of the work. Fig. 55 is a die and tap holder in which the socket for the die ov the tap is connected with the hnldoi' pi-oper by a C"()nil)iiiation Drilliuff ami C'hainfcriii": Tool pair of rolls operating in oppositely located slots. This gives the thread- ing tool considerable freedom longitudinally and assures accurate results even though the turret itself is not fed forward at the exact speed with which the die is drawn onto the work. Fig. 56 is a roller steady rest used where it is advisable to support a piece of work undergoing forming 76 THE CLEVELAND AUTOMATIC TURRET MACHINE operations. The method of adjustment is sufficiently clear to require no explanation. COMBINATION UNDERCUT FORMING AND CUT-OFF TOOL This style of tool, shown in Fig. 57, is used very extensively on the Cleveland machines. It will be noticed that it has an adjusting wedge so that the work diameter can be varied more or less. In using the form- FiG. 54. — Adjustable Boring Tool. ing tool in combination with a cut-off tool, the undercutting tool is set in advance of the cut-off; in other words, it passes under the work, com- pleting the outside of the piece and keeps in advance while the cut-off Fig. 55. — Tap and Die Hokler tool is severing the piece from the bar. In combination with the forming tool it rounds the corner or produces any shape desired before the cut- off tool on the opposite side of the slide has advanced to sever the piece. MACHINE CAPACITIES The regular turret machines of the type illustrated in this chapter are built in a wide variety of sizes; the smallest having a chuck capacity of ^-inch and turning lengths up to 1| inches, while the largest, which is intended for handling tubing of large diameter and for forming bevel gears and other parts from the bar, admits 6-inch material through the >chuck and is capable of turning lengths up to 6f inches. A line of MACHINE CAPACITIES 77 "plain automatics," operated on the same principle, as the machine described, are built with a single tool head in place of the regular turi-et. These are intended es])ecially for manufactui'ing studs, I'ollei's, sjiort screws, Fit:. 56. — Roller Steady Rest taper pins, etc., where the forming may be done entirely with the cross- slide tools. .Several sizes of automatic chucking machines are also built by this company, the.se being adapted for finishing castings and forgings Ik.. .')7. - Coinhiiiatioii I'lidercvit Forming aiiV' 'vV*^ ->) n Z.^/ Fig. 60. — Gridley Turret Construction CAM-SHAFT DRIVE The cam shaft is driven by worm wheel and worm shaft actuated by the well-known differential gear or "sun and planet" mechanism, the quarter-turn belt being shifted at the proper moment from fast to slow driving position,- or vice versa, by a forked guide operated through the medium of adjustable dogs carried by a disk on the cam or main shaft. This feed, as seen in Fig. 61, may be thrown out of action at any time by turning a small handle at the front of the bed, this handle being attached to a shaft carrying at its rear end the pawl which locks the ratchet wheel in this form of drive. Of the two pulleys, F is the one driving through planetary gears, the pulley making 70 revolutions to one turn of the worm G. When the belt is shipped onto pulley //, which is pinned to the worm shaft, the cam shaft is rotated rapidly for moving the tools to or from their cuts at high speed. TURRET REVOLVING AND LOCKING MECHANISM The turret rotating mechanism is driven, as in Fig. 62, by an inde- pendent worm and worm-wheel, also rotated by a quai'ter-turn belt at the rear of the bed. The locking disk A is keyed to the stem B of the turret and carries TURRET REVOLVING AND LOCKING MECHANISM 81 Fig. 61. — Feed Drive for Cam-Drum Shaft Policy DriTcn coDtinroiulj at a CooBtaot Sp««a, Left Hand End Elevation igjit Hand End Elevalioa Fig. 62. — Turret Hevohing and Locking Mechani.sm 82 THE GRIDLEY SINGLE-SPINDLE AUTOMATIC TURRET LATHE 4 tool steel shoes C into which the locking pin D enters. The locking pin is withdrawn by the lever E with its shaft E^ and arm E-, the upper end of which enters a hole in the locking pin. The lever E is operated bv the roll F, which is fastened in the edge of the cam drum. This is the cam drum between the columns of the frame. When this lever E has been moved forward far enough to draw the locking pin clear from the seat C, the arm E^, attached to the lever E, raises the latch G, and the spring H slides the shaft / with its clutch member /^ into engage- ment with the other clutch member /, which is driven constantly by the shaft J^ and its pulley J-; this causes the shaft I to revolve, and that in turn revolves the worm K, thus causing the turret through the worm K and worm gear L to revolve. It will be noticed that the end of the locking pin rides on the periphery of the locking disk A after the roll F has passed the projection on E. When the turret has revolved so that the locking pin drops into the notch in seat C, the shaft I with its clutch is moved endwise out of engagement with the constantly revolving member J, by the pin M in the lower end of the lever E-. In order to take care of the momentum of the revolving parts and clutch P, which is geared with the turret through the worm K and worm gear L, a spring .V is interposed, one end of which bears against the bracket which carries the revolving parts, and the other end against the worm K, so that when the turret stops revolving, the spring A'' allows the worm K to act as a screw, the worm gear L acting as a nut, so that it is not necessary to stop the movement of the revolving parts instantly. The worm K is splined to a bushing 0, but is free to move endwise on the bushing, the latter being splined to the shaft /. The object of the latch G and the spring H is to prevent the engagement of the clutches F and / until -the locking pin D has been entirely withdrawn from the inserted shoe C, then the further movement of the lever E with its arm E^ raises the latch G out of engagement with the collar /- on the shaft /. The movement of the lower end of the lever E'^ compresses the spring //, &o that when the latch G is clear of the collar P, shaft / is given a quick endwise motion to bring the two clutch parts together. There is a leather ring on each of the clutch parts so that when they are brought together by the spring H the turret is operated by the frictional contact between the leather rings. In fact the frictional engagement oftentimes accom- plishes the revolving of the turret without the necessity of the steel clutches. THE CROSS SLIDE The cross slide is operated by a cam under the turret. It is fitted to a heavy guide and a broad, taper, adjustable shoe is fitted to the top of this guide to take up any play. The slide may be utilized for either form- ing or cutting-off operations. When it is used for forming, the cut-off THE TURRET TOOLS 83 tool is carried in the pivoted arm at the back, this arm also being oper- ated bv a cam on the disk beneath. THE TURRET TOOLS The slides carried by the turret give plenty of room for tools of any class or size likely to be required; each slide is provided with a longi- tudinally placed screw for ailjusting the tools accurately to and from the spindle. Where de-ireli'->i)in(ll(' Plain Auloiiiatii- the chuck, a combination cutting-off and forming tool advances and completes the outer end of the piece; it is then fed through the right-hand spindle hood, the chuck mechanism on both spindles acting simultane- ously. The piece then partly finished is gripped in the right-hand chuck and the forming tool advances, finishing both ends as seen in Fig. 77. After the forming tool has advanced far enough to separate the two pieces it still continues to feed forward for a short distance until both ends are shaved clean and exact to size. As these operations take place on one piece after another, the finished parts are moved tin-ough the right-hand 93 94 CLEVELAND DOUBLE-SPINDLE PLAIN AUTOMATIC MACHINE spindle head, finally dropping into the pan fastened to the end of the machine. The spindle and cross-slide operations are controlled in prac- tically the same manner as on the regular turret machine built by the same company and illustrated in Chapter \L Fig. 77. — Work on Cleveland Double-Spindle Machine CHAPTER XI The Acmio Multiple-Si'Ixdle Automatic Screw Machine The niultiple-spiiuUe automatic screw machine built by the National Acme Manufacturing Company, Cleveland, Ohio, is illustrated in its latest form with single-belt drive in Figs. 78 and 70. When efjuipped for motor di'ivc the single driving pulley is replaced with a spur gear and the motor connected to tliis is carried on a bracket jjlaced at the l(>ft of the gear. Ik;. 7S. Acme .Multiiilo-Spintllo .Xutonuitic Screw Macliii.c The machine as shown consists ])rimarily of a cylindei- .1, Fig. 7S, hold- ing four stock-carrying spindles and a series of slides carrying tools which operate on all four bars from the side, top, and end at one time. As there are two slides oj)erating from op])osite sides of the machine, two from the top and one (the main slide, which is capable of cari'ying 96 THE ACME MTLTIPLE-SPINDLE AUTOMATIC SCREW MACHINE four tools, one for each spindle) from the end, it is possible to use eight separate tools at one time — two on each bar, one from the end and one from the side. After a bar has been operated upon in the first position by one pair of tools, it is carried on to the next pair by the cylinder which is indexed by quarter turns. In this manner, after three sets of tools have finished their work upon the piece, it is carried to the fourth position where the final tools (one of which is a cutting off blade) operate upon it. This Fig. 79. — Acme Multiple-Spindle Automatic Screw Machine (Rear View) gives a finished piece at each quarter turn of the cylinder. As all tools work simultaneously, the time required for the longest single operation is the time necessary to finish the piece. It is frequently possible to combine two or more tools, such as a box tool and a drill, two dies, die and tap, drill and countersink, etc., or to use special attachments, described later. In such cases more than eight operations are readily performed. The stock is fed in the manner generally adopted on automatic screw machines, all movements being cam controlled and positive. The length of feed and position of the gage stop are easily changed to meet the re- quirements of the work in hand. The gage stop on this machine does FEED rriAXGES 97 not occupy one of the end tool positions, but is so arranged that the stock is fed against it during the quarter turn of the cylinder on the smaller machines, and just before the tools engage the stock in the first position on the larger sizes, the stop being swung back to allow the tools to come into contact with the stock. DRIVING AND SPEED CHANGE MECHANISM The drive to the four work spindles is transmitted by the longitudinal shaft and connecting gearing as illustrated in the general views and in Fig. 80, and the speed-changing mechanism and cam-shaft drive are arranged as represented in Fig. SI. Acme Spindle Dri A change-gear system is used in connection with these mechanisms in order to transmit driving power, as well as facilitate rapid changes in the spindle speeds and tool feeds. The stock-spindle speeds are controlled by back gears .1, Fig. 81. When running direct, gears on the stud B are slipped out of engagement with those on the pulley hub and top shaft, or removed entirely. Direct drive is obtained by first sliding gears on the stud out of mesh, then binding together thimble C and pulley (or gear, if motor driven), with the two screws furnished for this purpose. When changing from direct speed, the two thimble screws are removed before placing the gears on the stud in mesh witli tlie gears on the })ullev hul) and shaft. To change the spindle speed, tlie vertical section of overlianging arm D is removed by removing screw E, after which thimble C is removetl, tlie pulley (or gear, if motor driven) slipped off of the top shaft and the gears slipped from the hub of the pulley antl stud, replacing with tlie gears to be used. FEED CHANGES Feed-rate changes are controlled by gears F, Fig. 81 through which the cam shaft is operated. The idle movements of the machine (those which occur when the tools are not operating on the work, such as feeding in of the rods, indexing of cylindei", movement of tool slide toward and from 98 THE ACME MULTIPLE-8PINDLE AUTOMATIC SCREW MACHINE the work, etc.) occur when the machine is running at the constant or direct speed, or when sliding chitch G is engaged with the teeth in cUitch collar H. Through the use of roller clutch J the feed-change gears remain idle during these movements. \'arious classes of work can be produced at a higher rate than is provided b}' the direct feed drive. This is accom- plished by the use of certain combinations of change gears and is clearly set forth in a gear table, supplied with the machine. The shifting of Fig. 81. — Spindle and Cam Shaft Change Gear and Driving Mechanism sliding clutch G is controlled automatically by arm K, Fig. 78, operated by dogs or cams on drum L; also by hand lever M. ^^"ith the hand lever to the extreme right, arm K is removed from the zone of the dogs or cams on drum L, and the feed mechanism is rendered inoperative, except on the slow or cutting speed. The lever cannot be moved in this direction dui-ing the idle movements, or when the feed mechanism is being oper- ated on the direct or fast speed, and when in this position cannot be CAMS AND CAM SHAFT 99 moved to throw the sliding clutcli in engagement with the teeth of the direct-drive clutch, thereby eliminating the possibility of trouble which might be caused by jamming the tools against the woi'k on the fast or direct speed. This hand lever will be found very convenient during the work of setting up the machine, as by its use the amount of hand cranking can be very materially retlucetl. Clutch G, Fig. 81, should always be in the neutral position wIkmi tlie hand. crank is being used. The shifting action of this clutch mav be regulated by slight adjustment of angular cam \\ and its proper engage- ment with the stationary clutches is assured by tension on the spring which operates plunger P, this tension being increased if found necessary by turning nuts R to the right. Frictions S and T are employed in connecting the feed-change gears to the sprocket shaft and the small sprocket to the worm shaft, their use being a safety measure as they will slip in case of accident causing unusual strain on the machine, and thus prevent the bi-eakage or dis- tortion of the moi'e vital parts of the mechanism. CAMS AND CAM SHAFT The cam shaft carries the drums and disk to which are attached the cams which control the several movements of the machine, and in addi- tion the indexing segment for the cylinder carrying the four woik spindles. The proper indexing of the cylinder depends upon the indexing segment, and especially upon the last tooth, which is made adjustable to compensate for such wear as may occur at this point. To drum or disk B, Fig. 79, are attached the cams or dogs which t)i)er- ato the lever controlling the change from the idle to working speeds of the machine, and with the exception of machines Xos. 51, 515, and 52 the lever operating the thread-starting mechanism. Cam drum (', Fig. 79, operates the main tool slide, and on machines Nos. 51, 515, and 52 the thread-starting mechanism. The grooves in this drum are for what are known as the " backing-uji" stiips, which are used to relieve the strain on tlie screws that liold the lead cam — the cam which feeds forward the main tool slide. The cross slots in this drum provide for adjustment of tlie cam which controls the rapitl move- ment of the tool slide toward the work before the cuts are started. Disk 7), Fig. 7i), can-ies the cams which operate the cutting-off and forming tool slides. There are two sets of screw holes in this disk for locating the cutting-off cam, one set of holes to be used when there is no operation to be i)erformed from the fourth position of the main tool slide, the other when this position is used. It is necessary to use the extra set of holes when an operation is being performed in the fourth position from the main tool slide in ordei' to delay tlie cutting-off operation until 100 THE ACME MULTIPLE-SPIXDLE AUTOMATIC SCREW MACHINE the tool slide recedes sufficiently to allow the tools in the fourth position to clear the work before the piece is entirely cut off. Disk E, Fig. 79, operates the cylinder-locking levers. On the small machines this disk is outside the leg. Disk F operates the oscillating gage stop on machines Nos. 53, 54, 55, and 56. Machines Nos. 51 to 52 are equipped with stationary gage stop and this disk will, therefore, not be found on these machines. Cam drum G carries the cams which operate the frictions, chucking and un-chucking levers, and feeding mech- anism. Cam shaft end play is taken up by collars at L. THE WORK-SPINDLE CYLINDER AND CYLINDER CASING The cylinder .1, Fig. 78, for the work spindles is of gray iron, the bearing surface of which is ground to size. The internal surface of the cylinder casing B is also ground to size; compensation for wear of either the casing or cylinder being provided by a slot in the casing. Contrac- tion and expansion of the casing is controlled by screws C and D. To contract the casing loosen the screws in top bracket E, turn screw C to the left, and screw D to the right. When proper adjustment is secured turn screw C to the right. To expand the casing turn screw D to the left, then screw C to the right, after which screw D to the right. Longi- tudinally the cylinder is held in position in the cylinder casing by a flange on the cylinder and adjustable clips F. When the cylinder is indexed by the segment gear G, Figs. 78 and 82, it is brought into correct position by plunger M, Fig. 82. When in proper alinement adjusting screw A^, Fig. 82, is resting upon half-round plunger P. Plunger M is designed to enter only a short distance into bushing R, the tapered portion of the plunger striking the upper wall which, with the assistance of springs S, insures perfect contact between adjusting screw A'^ and half-round plun- ger P. WORK SPINDLES, BEARINGS, ETC. The work spindles are of steel, chucks of the push type being used. Each nose piece is ground in place on its spindle. Bronze parallel bear- ings are used in the cylinder. The front and rear tapered bearings are of bronze, both running in hardened and ground steel bushings. The longitudinal movement of the spindles is adjusted for end play by turning collars A^, Fig. 83. To adjust the chucks to the rods, finger-holder 0, Fig. 83, should be turned to the right (after first unscrewing the set screw) if it is desired that the chucks grip the stock tighter, or if less tightly, to the left, the set screws being tightened after the proper adjustment has been secured. The feed chucks are threaded to turn right-handed and fit closely in the feed tubes to prevent their coming loose when the machine is in operation. As the work spindles rotate to the left the nose pieces have left-hand threads. WORK SPIXDLKS, BEARIXCS, ETC. 101 Fig. S2. — Iiulexin"; and Lockino; Mechanism Fiti. S.S. — Spindle Constructiun 102 THE ACME MULTIPLE-SPINDLE Al'TOMATIC SCREW MACHINE FRICTIONS The spindle frictions, Fig. 83, which make it possible to hold one work spindle stationary while the remaining three continue to rotate, are made up of four princii^al parts, viz.: sleeve .1; male tapered section and gear B; female tapered section C; spring seat D. The work spindles as already stated are driven by a gear attached to the spindle-driving shaft meshing with the geared portion of the male tapered section B, engaging female tapered section C, which is keyed to sleeve A; sleeve ^i being keyed to the work spindle, b'ections B and C are held in engagement by springs E. When sections B and C are not engaged, section B not being keyed to sleeve A rotates freely on it, and section C, sleeve A, and the work spindle remain stationary. Disengagement of members B and C resulting in the work spindle being held stationary is necessary, while threading, cross-drilling, side milling, or other special operations of this nature are being performed. Where the friction caused by lever F com- pressing springs E is insufficient to hold the work sphidle stationary, which may be the case when cutting coarse threads, adjustable plunger G located on the under side of bracket L (which bracket is attached to the cylinder casing) is brought into contact with lug M inserted in sec- tion C of the friction. This will prevent rotation of the work spindle during the threading operation. The length of time the work spindle must be held stationary is determined by the duration of the threading or special operations. The opening and closing of the friction is con- trohed by cams on cam drum G, Fig. 79, operating through a roll, lever A, and a toggle-locking device. The opening cam is positive, while the closing cam is adjustable on the cam drum. In the larger machines positive clutches are used in place of frictions to provide against slip- ping; these are operated in the same manner as the frictions on the smaller machines. MAIN TOOL SLIDE The main tool slide, Fig. 84, carries the tools usually carried in the turret of single-spindle machines, i.e., those worked from the end. Four is the maximum number of tools it will accommodate, although by the use of combination tools in these positions, more than four operations may frequently be performed. The locations of the several tools are designated as "positions." The first is the position from which the tools engage the bar on which the forming tool is operating. The second, that above and vertically parallel to the first position; the third, opposite to and horizontally parallel to the second position; the fourth, below and vertically parallel to the third position. The tool slide is moved toward and from the work by cams bolted MAIN TOOL SLIDE 103 to cam drum xi, Fig. 84, operating on a roll attached to adjustable slide B, which is bolted to the body of the main tool slide. It is good practice to have the shanks of tools extend as far back in the tool spindles as possible in order to secure increased rigidity. To make this possible two methods of adjustment are provided when chang- ing from long to short work and vice versa, viz., the changing of the posi- tion of the lead cam on the cam drum, also that of adjustable slide B, Fijr. Si. l''iu. 84. — .Main Tuul Slide When it is necessary to pci'form an operation from the fourth posi- tion in the tool slide, about 4 niches should be taken off the wide end of the lead cam on Nos. 53 to 56 machines inclusive, and about 3 inches on the Nos. 51 to 52 machines. This is done to allow the tool in this posi- tion to clear the work before the piece is cut off. If desirable, the tool spindle in the second position can be rotated by means of the gears driven by the sliding gear keyed to the spindle-driving siiaft for driving the thi-eading spindle. The back plate attached to the rear of the vertical portion of the tool slide with screws and spacing collars carries a stud u})oii which tlie intermediate goar that drives the tool 104 THE ACME MULTIPLE-SPIXDLE AUTOMATIC SCREW MACHINE spindle in this position rotates. This spindle may be driven by loosen- ing a collar at the rear sufficiently to allow it to rotate freely, unscrewing a nut on the stud and moving the stud sufficiently to bring the interme- diate gear into mesh with the gears on the spindle-driving shaft, then tightening the stud again by screwing up the nut. The rotation of the second position tool spindle is found very convenient in cases where a very small hole is to be drilled. Screws are provided for use in adjusting the position of the individual tools in the tool slide and also serve as a gage stop in re-setting tools in their original positions after they have been removed from the slide. THREADING MECHANISM The threading mechanism is so constructed as to allow for the thread- ing operation as much time as is consumed in the longest milling, drill- ing, or forming operation, thus insuring good threads, and long life for the threading tools. Oil is forced through the die spindle into the die from the rear, thus providing ample lubrication. The die spindle is rotated by means of sliding gear E, Fig. 85, which is keyed to and driven by the top shaft. Fig. 85. — Speed Change Gear for Threading Spindle When the die spindle is not in use clip F can be raised and the gear slipped out of mesh with the threading-spindle gears. When clip F is in engage- ment with the groove nearest the teeth in gear E the threading spindle sleeve will be driven direct and at its highest rate of speed. When clip F is in engagement with the groove farthest from the teeth in gear E the sleeve will be driven through the intermediate and compound gears G and H at its lowest rate of speed. The threading-spindle sleeve rotates about seven times as rapidly when driven direct as when driven through intermediate and compound gears. In threading brass or cutting very fine threads on soft steel, the direct drive may be used. In most other cases it is advisable to use the intermediate drive. The threading spindle is driven by pins A, Fig. 86, attached to the threading-spindle sleeve, engaging pin B in the spindle. Pin B is adjust- THREADING MECHAN ISM 105 able for length, this adjiJ^tment being used when the pitch of the thread is such that the forward travel of the tool must be faster than that of the tool slide. These pins are furnished in various lengths. AVhen the tool becomes slightly dulled, or when the die has a shallow throat (which is necessary when the thread is to be cut close up to the head or shoulder of the work), the device in Fig. 86 is brought into use. This is known as the thread starter and operates as follows. Fig. 8(3. — Threadinsi; Mechanism At the time the tool is in position where it just touches the end of the blank to be threaded, roll D should be adjusted so as to be brought into contact with swinging pawl E, the roll holder being adjustable on rod F, which is operated by an adjustable cam on cam drum B (Fig. 79), through lever G, Fig. 86. Spring H compensates for any slight variation there nuiy be in the length of the blank, making the starting of the tool positive, but the operation of the mechanism flexible. End play in the threading-spindle sleeve is taken up by collars L. After the tool has completed the operation of threading, the work spindle is released (as explained in connection with the operation of the frictions) and the tool runs off when the ratchet A' on the rear end of the die spindle engages flexible pawl M, all receding with the tool slide. In setting tools for threading, before starting the machine the ratchet should clear flexible pawl M from J, to f\ inch when pins .1 and B on the threading- spindle sleeve and spindle are placed end to end. With the regular threading mechanism only right-hand threads can be cut, but the machine can be equipped with left-hand threading attachment when so desired. 106 THE ACME xMULTIPLE-SPINDLE AUTOMATIC SCREW MACHINE FORMIXG AND CUTTING-OFF SLIDES These slides are made adjustable for position lengthwise of the ma- chine. This makes it possible to change the longitudinal position of the cutting-off and forming tools without disturbing the tools themselves. The cutting-off tool when of the blade variety is adjustable for hight by means of a screw in the slide. A gage for setting the forming tool to the proper hight is furnished with each machine. On machines Nos. 52, 55, and 56 both the levers which operate the forming and cut-off slides H. Figs. 78 and 79, and the bracket in which they are pivoted, are drilled in two separate locations. This double drilling makes it possible to form deeper and cut off larger diameters of stock when the levers are pivoted in the lower holes without substituting cams of a greater throw or travel, as designated in a table accompanying the machine. TOP SLIDES Two of these slides are provided, operating in second and third positions as represented in Figs. 78 and 79. They are adjustable length- wise of the machine and are used for nurling, thread-rolling, shaving, light forming, etc., and are very useful in producing man}' varieties of work. Their operation is pro^•ided for through bar cams attached to the tool slide. Cam il/. Fig. 79, moves the top slide toward, and cam A'^ from the work. These cams can be readily filed to any angle, thus providing whatever feeds may be deemed desh-able for the tools in use. In operating tools in these top slides, care must be exercised in having cam M notched and the tools so set that the slides will be in their orig- inal position and the tools out of the way before the indexing of the cylinder carr^-ing the work spindles takes place. The cams rarely need changing as the set provided with the machine covers a wide range of work; extreme cases, however, require a faster or a slower feed. TOOLS AND ATTACHMENTS Fig. 87 illustrates the machine as it appears equipped with tools for each position for operation on four rods at the same time. Fig. 88 is a group of collets, feed chucks, and jaws. Fig. 89 illustrates various types of box tools with back rest jaws, roller rests, etc. Fig. 90 shows die, tap and drill holders with button dies, tap and drill bushings, die exten- sions, etc. The die holder at the top of the group is a telescopic device used in cutting two threads. A tap is frequently used in place of the second die. At the center and left of the group is a friction die holder used for threading close to a shoulder on small work; a button die holder and extension being shown just to the right. Fig. 91 is a set of tools for machining a stud shown at the center of TOOL?; AND ATTACHMEXT^ 107 nd Tool Positions the group. As this work is indexed through the four positions, the tools operate as follows: Forming tool and lower box tool in the first position; shaving tool and box tool with roller rest, second position; die in the third and cut-off tool in the fourth position. The shaving tool shown just above the die is similar to a number shown in Fig. 92, which also includes several types of nurls, and a thread-rolling tool. The shaving tool is mounted in the machine as illustrated in Fig. 93. It consists of a holder carrying a rest and a shaving blade, the holder being pivoted to allow Tic;. 88. • — Spring-Collets and Feed Chucks 108 THE ACME MULTIPLE SPINDLE AUTOMATIC SCREW MACHINE UiG. 89. — Box Tools of Various Types the blade and rest to find their own center. As the distance between blade and rest when once set is positive, and as the tool is allowed to find its own center, it produces very accurate results. Fig. 90. — Die, Tap and Drill Holders TOOLS AND ATIWCHMENTS 109 I'k;. 91. — Set of Tools for Machining a Stud The thread-rolling tool mounted as shown in Figs. 93 and 94 is espe- cially adapted for rolling a thread at the back of a shoulder. It consists of a thread roller mounted in a holder which is secured in the rear top Fig 92. ■ — Sliavinp, Tliicad RDllins;, and Nurlinfj Tool.- 110 THE ACME MULTIPLE-SPINDLE AUTOMATIC SCREW MACHINE slide. It produces smooth, accurate threads and is obviously appli- cable to many cases where a die cannot be operated. At the same time it may be used satisfactorily at the front side of a shoulder where ordi- narily a die would be employed. Fig. 94, which is a rear view, shows a Jg ^^MP^ ^^^ ^3t^ a^ '^A/^^Ki ^sKf ^^^%^^^^^H •^P Fig. 93. — Shaving and Thread-Rolling Tools in Position Fig. 94. — Work Before and After Thread- ing with Roller piece of work before and after threading and clearly illustrates the manner in which the threading roll can be applied between a shoulder on the work and the face of the chuck. M I L r,IX( ; ATTAfH.MEXT; 111 CROSS-DRILLIXG ATTACHMEXTS The cross-di'illiiip; attachment shown in Fig. V)o is operated in the third position, where prcnision is made for stopping the rotation of the stock to aUow for threading and other operations. The attachment is secured to the cut ting-off slide and actuated by the cutting-off lever. On the larger sizes of machines sufficient feed for the drill is obtained by an aux- iliary lever at the side of the attachment, -which increases the throw of the cam. Adjustments are provided for governing the depth and posi- tion of the hole in the work. The drill spindle is operated by a b?lt from a countershaft. By using a combination tool it is possible to drill and countersink a hole at the same time. Fig. 9.5. — Cross-Drilling Attafhinent Cross drilling from the top of the piece may be accomplished by means of an attachment used in place of the top slide over the third position. This attachment may also be used in conjunction with the one on the cutting-off slide, the holes being drilled at a given angle to each other. Also, when required, the machine may be modified to allow the two holes to be positioned at any angle with each other between 90 degrees and a few degrees from parallel. MILLIXU ATTACHMEXTS There are two forms of end milling attachments for the machine, one being driven by bolt; tiie otiier l)y gears. The latter type is illustrated in Fig. U6, and is adapted to the iioavier classes of work; for example, 112 THE ACME MULTIPLE -SPINDLE AUTOMATIC SCREW MACHINE where two cutters are required. Tliese attachments are operated from the main tool slide, opposite the third stock position owing to the neces- sity of having the stock stationary during the drilling operation. Either Fig. 96. — End-Millino; Attachment attachment can be used in conjunction with cross-drilling or side-milling attachments, but are not applicable where threading operations are re- quired as their position on the machine is then occupied by the threading spindle. Fig. 97. Side-Milling Attachment A side-milling attachment is shown mounted on the cross slide in Fig. 97; and in Fig. 98 a slotting attachment is illustrated, the work handled in this device being received from the spindle by a turret holder and carried around in front of the saw or saws as the case may be. After the operation the piece is ejected in the manner indicated. MACHINE SIZES 113 Fig. 98. — Slulling; ami Milling Attachment MACHINE SIZES A setting-up print for the different sizes of Acme machines is repro- duced to small scale in Fig. 99 with the leading over-all dimensions, belt widths, etc. The several sizes in which the machine is built range from a chuck capacity of ^-inch and feed length of 2^ inches to a chuck capac- ity of 2^ inches and feed length of 10^ inches. V-K--5 Uk).Im B.r.^ Sa.nb.. A B c D E F G u I J K r. M Cib. 515 ii'a 6'3':7'5 'iO'a'jX'l 30 2'0' 10 1 20" I3)i'j 15 ■ 3' 4 i 430 62 12 a 5'3^ J'O jO'ti' i!'l'|3'0' •2 B lo' 20' 13H li" 3 ' 4 a" 3S5 63 I3'l( !'0' o'lulo'o' i'0)4 3'o'|2'8Ju' 20' 13541 li" 4" i'i 385 ; 64 130 7';' S'lljO'o i'l")i-i'0"yi'i"\U' 20 l.iHl 15" 4 ■ 4V'i315 1 65 ^0 I'i' o'uls'o'a'H'jia'ufi'o'jn' 20'|13H|13 i' -I'ujiaii 66 13'6 9'o' d'lljo'o' L'l' 3'g' •J'5"|2U' 20'|13>4'll5" 4" o'a'laio 1 Fii;. It'.t. — ()\c'iluail Works and Overall Dimensions Acme Automatic Screw Machine CHAPTER XII The Universal Multiple-Spindle Automatic Screw Machine The general design of this machine, which is built by the Tniversal Machine Screw Company, Hartford, Conn., is well shown in the front and rear views, Figs. 100 and 101. Fig. lOU. — Universal Multiple-Spindle Automatic Screw Machine The machine has five spindles and is operated from the countershaft by a single belt passing over the plain driving pulley shown at A, Fig. 102. The five spindles are carried in a cylinder which is indexed to bring one spindle after another in front of each of the five tools in the tool slide. The latter is fed forward by the cam underneath, bringing all the tools into action sinmltaneously, and a piece is completed at each advance of the tool slide. 114 OPEHATIOX OF THE SPIXDLES 115 opp:ration of the spindles For ordinary turning, forming, drilling, and other operations, the spindles run in a left-hand direction; for threading, the sjjindle with the work is run slowly to the rigiit during the operation and upon the die reaching the proper distance the spindle is reversed and the die rapidly drawn ofif the work. As will be seen, each spindle has at its rear end two spur gears. The one nearest the turret is operated by a gear on a centi'id sleeve passing thi'ough tiie turret and supported at its right-hand li(i. Kll. I'liivcrsal .Multiiilc-Spiiidlc Automatic Screw .Mncliiiic (Hear \'ic\v . end as shown at B, Fig. 102. the gears C and D serving to drive this sleeve or hollow shaft, thiough which pas.ses shaft E. This latter shaft carries at its left end gearing engaging the outer gears on the spindles for driving them during threading oi)erations. The drive for shaft K is transmitted through the medium of change gears in train F at the outer end, connect- ing with the right-hand end of the short driving shaft G. It is obvious that by the series of change gears suitable si)indle s])eeds for threading may always be ()l)taine(l. An impoi'tant featui-e in this spindle-driving 116 rXIVERSAL MULTIPLE-SPIXDLE AUTOMATIC SCREW MACHINE mechanism is a positive type of clutch (operated by an arm at the rear) for connecting the spindles with either the left-hand turning or right- hand threadins; motion. THE CAM-SHAFT DRIVE The cam shaft is also driven from short shaft G, Fig. 102. This shaft by means of bevel gears H drives shaft / upon which is mounted freely pulley J. which may be secured to / by operating lever K and so engaging the conical clutch with the pulley. This pulley is belted to the pulleys below for driving the cam-shaft gearing, the arrangement of which is shown clearly in Fig. 103. and when the lever K, Fig. 102, is moved to the right the friction clutch in J is disengaged and a brake L applied to the pulley, stopping it and the cam shaft instantly. e3:::::l::- Fig. 102. — Dri\'ing Mechanism of Universal Automatic Screw Machine This is a convenience especially when setting up for a piece of work as the feed motion may be started and stopped at will without stopping the spindle. Of the two pulleys placed side by side as in Fig. 103. on the worm shaft for operating the cam-drum shaft, the outer one drives the worm shaft direct for rapid traverse of the tools during idle or non-cutting movements, while the inner one drives the shaft through change gearing, by which the recjuisite rate of feed is always readily obtainable. The short belt is of course automatically shifted from one pulley to the other during THE LOCKING BOLT FOR THE SPL\DLE TURRIOT 117 the cycle of operations; the shifter lever and dogs for contr()lliii.SrixDLE Aitomatic Tlrhet Lathe In the accompanyino; engravings is illustrated the (liidley multi])le- spiiulle automatic turret lathe built by the Windsor Machine Company. The single-spindle automatic built by this concern is illustrated in Chapter vn. The four-spindle machine forming the subject of the present chapter is well illustrated bv tiie general views. Figs. 105. 106. and 107: its con- I'lc. lO.j. — Gridley Maltiple-.'^piiKlle Autoniatic Turret L;itlie struction will be understood by referring to these half-tones and to the details presented in the line drawings. Like the single-spindle machine referred to, this automatic has a four-sided slide far carrying the " tur- ret" tools; the tool slide in this ease, however, is not rotated to bring 119 120 THE GRIDLEY MULTIPLE-SPINDLE AUTOMATIC TURRET LATHE the tools one after another into position for the successive cuts, as the four spindles themselves are carried in a cylinder that is indexed step by step to bring each spindle successively into position for the bars of stock to be operated upon by the various tools. All of tlie tools held by the tool slide are fed forward together, one tool rough-turning the ]:)ar in one spindle, another tool taking a finishing chip on the piece held in the next spindle, a die threading the piece in the next spindle, and the finished piece being cut off and a new length of -*:?\ Fig. 106. — Gridley Multiple-Spindle Automatic Turret Lathe (Rear \'ie\vj stock fed through the chuck at the fourth position of the spindle, or such other operations being performed as the piece may require. As all of these operations are performed simultaneously, it will be seen that the time to make a completely finished piece and cut it off will be only the time required to perform the longest operation plus the time required to return the tool slide, revolve the spindle cylinder, and move the tools back to their cutting position. THE SPINDLE AND TOOL SLIDE The spindles, their carrying cylinder, and the tool slide are shown in Fig. 107 removed bodily from the machine; this half-tone reveals also a number of other interesting features of construction. A horizontal sec- tion through one of the spindles is given in Fig. 108, and it will be noticed THE SPIXDLE AND TOOL SLIDE 121 that the spindle takes a long, straight bearing in a lumen-bronze sleeve which admits of ready renewal as a whole in the event of sufficient wear occurring to make this necessary. The hub of the cylinder around which the four spindles are located is extended, as represented in Fig. 105, to form a long bearing for the tool slide, this feature of mounting spindles and tool slide on the same member having been adopted in conjunction with the feature of large bearing areas to insure permanent alinement of spindles and tools. The bearings of the spindle-carrying cylinder are on the large diameters .1 and./^. Fig. 107. In the event of any wear taking place between these surfaces at either end and the bearings formed in the main frame of the machine, the alinement of spindles and tool slide need not bo affected, as l^oth will simply move together. Fig. 107. — Gridley Multiple-Spindle Automatic Turret Lathe with Spindles and Tool Slides Removed In addition to the features ju.st described, Figs. 105 and 107 show clearly the method of preventing the tool slide from rotating, the arrange- ment consisting of an arm attached to the tool slide and machined at the outer end to fit a longitudinal guide bar located as represented at the top of the machine. The spindles have the usual collets and stock-feed device, and are driven by the pulley shown at the right-hand end of the machine in Fig. 122 THE GRIDLEY MULTIPLE-SPINDLE AUTOMATIC TURRET LATHE 105. This pulley is keyed to one end of a driving shaft running through the center of the spindle-carrying cylinder as in Fig. 108, and carrying on its other end a gear meshing with a gear keyed on each of the spindles at the rear end of the bearing. The spindles are run constantly in one direction without stopping or reversing for the purpose of threading, that operation being taken care of by the threading mechanism to be referred to later. Fig. lOS. — Spindle Construction OPERATION OF THE TOOL SLIDE The cam shaft C, Figs. 107 and 109, carries the cams for operating the tool slide and the forming and cutting-off tools; the cams for operat- ing the chuck and feeding the stock; and the mechanism for revolving the cylinder. It is driven at two speeds, one of which is comparatively slow for use during the time the tools are cutting, the other a high speed, for returning the tool slide and revolving the spindle cylinder. During the slow movement (while the tools are cutting) it is driven by a worm D, Fig. 109, on the spindle-driving shaft, through the change-gear box E, worm shaft F and worm gear G keyed on cam shaft ('. When the tools have finished cutting, the loose pulley H, which runs at a constant speed, is clutched to the worm shaft F. The drawing shows a toothed clutch for this connection, but a friction is now used instead. This method of driving the cam shaft gives a c^uick change feed for the cutting tools and a constant maximum speed for what are termed "idle movements," irre- spective of the rate of speed during the cutting period. The quick-change gears in the feed box E are controlled by two handles, the lower one / having three locations, corresponding to the feed cam used, there being TURNING AND THREADING APPARATUS 123 three of these cams furnished, one for work not over 2 inches long, one for work between 2 and 4 inches and the other for work ranging between 4 and 6 inches in length. Although the 6-inch cam can be used for the shortest work, there is of course an appreciable loss of time in moving the tool slide its full travel when working short pieces. When the lower Fig. 109. — Feod-Driving Mechanism handle is in the position corresponding to the feed cam which is being used, the upper handle J can be placed in any one of the six positions to give the feed desired, the figures 75, 100, 125, 150, 175 and 200 represent- ing the revolutions of the .spindle to one inch of travel of the tool sliile. TURMXC AND THREADING ATPAKATUS The form of tool slide allows a tuiiiing tool to be used identical with that employed on the (iridley single-spindle automatic turret lathe. The tool sliile has sufficient room to allow of one tool l^eing placed back of another. As the spindles are driven constantly in one direction, as stated above, and in order that a high cutting speed for the turning tools and a low cutting speed for the tlie can ])e used, it is necessary to rotate the die 124 THE GRIDLEY MUTIPLE-SPINDLE AUTOMATIC TURRET LATHE at a speed slightly less than the speed of the spindle while threading, and at a higher speed when running the die off the piece. This is accom- plished by means of two gears on the spindle-driving shaft, these gears meshing with two loose gears on the threading shaft, vrhich in Figs. 105 and 106 is shown immediately above and to the rear of the tool slide. These gears are of such ratio that when one of them is clutched to the die shaft it will rotate the die at a speed slightly less than that of the spindle; when the other gear is clutched to the shaft, the die will rotate at a higher speed so as to run off. When a left-hand thread is being cut, the die rotates faster than the spindle during the threading opera- tion and slower when running off. Fig. 110. — Cylinder Revolving and Locking Mechanism THE INDEXING MECHANISM The mechanism for revolving the spindle cylinder is illustrated by Fig. 110, which also shows the method of operating the locking bolt. Arm K mounted on the cam shaft carries a cam L for withdrawing the locking bolt M and has at its inner end a roll which at each revolution of the arm enters the channel in the face of the cylinder flange and rotates the cylinder one quarter turn, the locking bolt then dropping back into the next notch. The various sections show the cylinder just before the rotary movement commences and just after it has taken place, the lock- ing bolt being shown in place in one view and withdrawn in another. Till-: IXDKXIXG MECHANISM 125 Further explanation of the mechanism is unnecessary as the drawings illustrate the scheme fully. It may be stated, however, that the index notches for the lock bolt are formed in tool-steel shoes, secured in rect- ano;ular pockets in the peripliery of the cylinder. The machine illustrated has a capacity for 1^-inch round stock, 1-inch hexagon, and f-inch square stock. CHAPTER XIV The Cleveland Automatic Machine with Magazine Feed The magazine attachment for enabling the Cleveland automatic turret machine to handle small castings and forgings requiring opera- tions on one or both ends is represented in Fig. Ill, which illustrates Fig. 111. — Cleveland Automatic Turret Machine with Magazine Attachment the appliance in working position. The attachment is made in two forms, the older model being placed on the rear of the cross slide and oper- ated by a cam on the regular cam shaft engaging with levers at the rear of the magazine. The later design or tilting magazine, as illustrated, is mounted on a shaft held horizontally by two upright brackets fastened to 126 THE CLEVELAXD AUTOMATIC MACHINE WITH MAGAZINE FEED 127 arms on the bed of the machine, and is tilted in front of the turret when the conveyor or transfer device is in position to take a piece out to be chucked; it is then tilted back avoiding interference with tools in the turret or on the cross slide. It is operated in the same manner as the older model. The conveyor is held in one of the tool holes of the tur- ret. It grips the part in the magazine at the proper moment and carries it in line with the spindle, where the work is chucked, machined, and ejected to make way for the next piece removed from tlio magazine. li. Turning, Boring, anel Fatin^ 140 THE POTTER & JOHNSTON AUTOMATIC CHUCKING MACHINE TOOL RECORD Figs. 129 to 132 show the four pages of a convenient tool record sheet issued by the manufacturers and on which are recorded the tool and dog settings, change gears, etc., for a piece after the work has been set Fig. 126. — Turning a Spoked Fly-wheel up. At any time afterward the settings may be readily duplicated by simply referring to the sheet, the features and advantages of which are well brought out in the illustrations. Fig. 127. — Machining a Gas Engine Piston MACHINE C.\PACITIES, ETC. The 8^ X 16 inch machine illustrated swings 20 inches over the bed and 10 inches over the cross slide. The travel of the cross slide each way is 5^ inches. The 5^ x 10 inch machine swings 17 inches over the bed and 10 inches over the cross slide. The gear-driven heads of the type shown are operated from a single-speed countershaft driven by a pair of MACHINE CAPACITIES, ETC. 141 tight ami loose pulleys and carrying a plain pulley belted to the machine. The countershaft for the machines with direct-belted head is operated by three-step cone pulleys. When the machines are equipped for motor drive the motor is mounted on a bracket directly behind the head. Fig. 128. — Some of the Work done on the Potter cV: Johnston Machine Either size of machine with the smaller spindles may be equipped with a lever chuck which can be operated to admit or release work with- out stopping the spindle, this being of especial advantage when machin- ing small work from the bar or handling comparatively light castings and forgings. 142 THE POTTER tt JOHNSTON AUTOMATIC CHUCKING MACHINE THE POTTER & JOHNSTON AUTOMATIC CHUCKING MACHINE 143 * o O S - 5 i!il?1i^8=f •*!•:? ^ 3| ^ K I Si" s: ."O^ i lis III III '2 -^ CHAPTER XVII The Gridley Semi-Automatic Pistox Rixg Machine This machine is in general design quite similar to the Gridley auto- matic machine for bar stock described in Chapter VII. It is constructed especially for making from the casting piston rings ready for grinding on the edge. The operator secures the casting to the studs in the face plate and the machine then bores the inside, turns the outside eccentric, and cuts the ring off from the casting automatically. Fig. 133 shows P^iG. 133. — Gridiey Semi-Automatic Piston Ring Machine the machine as a whole; Fig. 134 illustrates the method of holding the special casting to the face plate and shows the means of operating the tools; Fig. 135 is a drawing of the casting from which the piston rings are made. ECCENTRIC TURNING MECHANISM Fig. 136 is a construction drawing of the eccentric turning mechanism. In this engraving A represents the head of the machine carrying the spindle 144 ECCENTRIC TURNING MECHANISM 145 Fig. 134. — Boring, Turning, and Cutting Off Piston Rings N'otch in Castinsa $4 -P^ *ot= ' J ^ i ^ Thi5 Inside Diameter must Run true with -^ "rff ""n three H Holes la J Flange for holding &^ = 1 3 Casting to Face-plate. ■i^'. - — w •S.", =3 kVi8 ,-/ 1 Fig. 135. — Casting from wliich Piston Rings are Made Fig. 136. — Eccentric Turning Mechanism for Piston Rings 146 THE GRIDLEY SEMI-AUTOMATIC PISTON RING MACHINE B to which is attached the face phite C. This face pLate carries the gear D which meshes Avith the driving gear E, to which is attached the coupling F pinned to the shaft G. This shaft is supported in the slide H by the two bushings / and /'. It carries the eccentric J and drives it by the key K which is free to move endwise in the keyway in the shaft G. The eccentric J is free to revolve in the square l)lock L, and the latter is free to move vertically in the guideway in the auxiliary slide M. This arrangement gives the slide M a reciprocation for each revolution of the spindle; the gears D and E being of even diameter. It will be noticed that the construction provides an oil pocket at 0, which keeps the parts thoroughly lubricated. The gear E runs free on the bushing .Y held in the frame of the machine by the cap Y. The same bushing .Y acts as a bearing for the back-gear shaft which drives the spindle. CHAPTER XWll The Prentice Multiple-.Spixdle Auto:\iatic Turret Machixe The multiple-spindle automatic built by the Geo. G. Prentice Co., New Haven, Conn., is shown in the accompanying illustrations. This machine is designed for performing boring, turning, threading, and other operations on castings, forgings, and similar parts, also on pieces that Fig. V.n. — Prentice Multiplc-SpIndle Automatic Turret Machine have been finished on one end in a bar-stock machine. It is especially adapted to the handling of such parts as air-brake-valve bodies, couplings and nuts, globe valves, grease cups, compression hose and fuller bibbs, gage- and ball-cock bodies, valve stems, etc. The machine shown has four spindles, these being arranged in the manner indicated in Figs. 137 and 138. Each of the spindles carries a tool for a different operation, and the work is automatically indexed and fed up to the tools by a cam drum, which will be seen in Fig. 137, near the right-hand end of the 147 148 PRENTICE MULTIPLE SPINDLE-AUTOMATIC TURRET MACHINE machine. The work carrier, or turret, consists of a chuck provided with five distinct sections or sets of jaws, each pair of jaws except tlie upper one being in line with one of the spindles; the upper section forms the point at which the operator feeds the work to the chuck. Fig. 138. — Prentice Multiple-Spinclle Automatic Turret Machine THE DRIVING MECHANISM The drive for the four spindles and cam drum will be understood from the general views. The first spindle — the one in front — is geared, as shown, to a shaft driven independently from the counter, while the two lower spindles are geared together and driven by the large pulley at the end of the head. The threading spindle is provided with friction reversing pulleys and back-geared, the ratio in the case of the machine illustrated (which is known as the No. 23) being 4 to 1, while the lower spindles are geared from their driver in a 2.7 to 1 ratio, and the front spindle in a ratio of 2 to 1. The cam shaft which feeds the work carrier up to the tools is driven from either the third or fourth spindle by change gearing extending to a shaft at the rear of the bed, this shaft being con- nected with the cam shaft — which extends the full length of the machine — by bevel and worm gearing. THE FEED The feed drum is adapted to receive a cam strip fixed at the required angle, this being determined by the length of the longest cut required on the piece of work. An adjustable ring on the threaded end of the chuck shaft, or turret bar, forms a positive stop for each forward move- ment of the work to the tools. This stop collar will be noticed just to the rear of the indexing mechanism which brings the work into alinement with one spindle after another until completed. The feed clutch may INDEXING FACE PLATE 149 be thro\vn out of gear and the feed instantly stopped by shifting the lever shown near the left-hand end of the machine. The chuck may be fed up by hand, when adjusting tools for new work, by turning to the left the worm shaft at the end of the bed. OPERATION OF THE CHUCK The construction of the chuck is shown in Fig. forms a two-jaw chuck opened and closed b}^ a right- and special false jaws are, of course, fitted to hold As already stated, the work is placed in the uppermost and the first indexing movement then brings it int in the first spindle, where the first operation is perfor time a second piece of work has l^een placed in the the chuck, which is then in the upper position, and 139. Each section and left-hand screw, any shape of piece, section of the chuck, line with the tool med. In the mean- following section of when the first piece Fig. 139 Fig. 140 Chuck and Face Plate for Prentice Turret Machine is brought into line with the second tool, the first tool is operating on the second piece; thus each indexing movement presents each piece of work to a different tool and four operations may be carried on simultaneously; the operator simply takes out the finished parts and puts in the rough work without stopping the machine, and ordinarily can attend to two or more machines. While the tools are cutting the chuck is supported and relieved of strain by a bracket which slides under the ledge of the chuck at the front of the machine. This bracket is visible in Fig. 137, and, as there shown, is attached to a lever which automatically draws it back out of the way of the chuck before the latter indexes, and then moves it to supporting position again before the tools start cutting. A taper bushing in the chuck body forms a means of compensating for wear between chuck and turret bar. INDEXING FACE PLATE For holding work that has been finished on one end and requires a second operation, an indexing face plate is used in place of the chuck. 150 PRENTICE MULTIPLE-SPINDLE AUTOMATIC TURRET MACHINE This face plate, as shown in Fig. 140, has five drawback studs or work arbors, which are threaded to receive work having internal threads, or provided with threaded collets for externally threaded work. After a piece of work has been screwed on a few turns by hand, a half turn of an eccentric stud draws it back tight against a hardened collar. The spindles of this machine are ground and run in bronze bearings, the front bearings being taper, and all but the threading spindle have tool holders forged solid on the spindle. The frictions on the threading spindle are of an expanding ring type and controlled l)y a lever contact- ing with a tripping disk on the cam shaft. When an automatic opening die or collapsing tap is used, the threading mechanism is locked in the forward position, and the reversing belt removed. TOOL EQUIPMENT Fig. 141 illustrates some of the tools adapted to this machine. The one in the upper left-hand corner is for cutting external and internal Fiu. 141. Prentice Turret Machine Tools annular grooves, and consists of a shank and head with a cross slide and cutter moved at right angles by two wedges. For internal grooves the tool is carried at the center of the slide. A spring-actuated rod returns the slide as soon as the pressure on the work is removed. The tool at ROTARY CUT-OFF 151 the right is a hollow mill which automatically opens upon the completion of the cut. The three tools in the second row are tap and die holders, the middle one being a combination floating affair for cutting external and internal threads at the same time. The tap holder proper slides on two studs in the threading spindle, and the die holder on two studs in the tap holder, thus allowing a tap and die of different pitch to be used together. Both types of tap and die holders shown are arranged to be led on the work by feed mechanism. An automatic opening die is shown in the lower left-hand corner, and at the right are a j)air of adjustable roughing and finishing turning tools. Among other tools used are boring and turning tools, counterbores, etc., made of flat bar stock dressed on the grinder and inserted in holders. UNDERCUTTING TOOLS Some details of the tools for cutting external and internal grooves of any desired form are presented in Figs. 142 to 149 inclusive. The tool, Fig. 142, is placed in one of the spindles of the machine and operated by an angular wedge and cross-slide mechanism, the wedges being made with the proper angle to give fast or slow cross motion to the cutter head. For external cuts, a ball-bearing pilot receives the thrust of the piece of work as the chuck is fed up to the tools, and this pressure forces the cutter head back on the wedges and draws the cutter down into the work. When the advance of the work ceases, and the chuck starts to back off, the spring in the hollow spindle forces the cutter head out on the wedges and the tool is drawn out of the work. For cutting internal grooves, the cutter is placed on the opposite side of the head from where placed for external work, and the same taper wedges are used for both forms of cutting. INTERNAL OPERATION Fig. 143 shows the shape of the wedges. Fig. 144 the ball-bearing pilot. In Fig. 145, neck a is an external cut made with this tool. For internal cutting a circular or single-point tool is mounted on a special head used in place of the cutter head shown in Fig. 142. Fig. 146 is the cutter used for the inside groove h in Fig. 145. Fig. 147 is the cutter used for simul- taneously forming the two inside grooves c d in the work. Fig. 148. On this work the cross motion of the cutter head does not begin until the cutter has entered the work and the face of the work comes in contact with the steel-thrust washer mounted on the cutter head. ROTARY CUT-OFF There are certain classes of work, such as valve, gage, and compression- bibb spindles, which are cast with a chucking lug, from which the finished piece is severed after all the operations are performed. For this work 152 PRENTICE MULTIPLE-SPINDLE AUTOMATIC TURRET MACHINE --3^ ITL. vf/////y////// ■^yyy^>->y^\ ' FIG. 142 Undercutting Tools for Turret Machine COUNTERSHAFT, MACHINE SIZES, ETC. 153 a rotary cut-off tool is mounted in place of one of the regular spindles of the machine. As the tool must traverse a considerable length over the finished surface of the work to bring the cutting-off tool to the point of operation, the cutter head is fed out by means of the rear lever and cam as shown in Fig. 149. The advance of the chuck brings the work in con- tact with the ball-bearing pilot in the cutter head, and at the same time the forward lever and cam feed the cutter into the work, the feed being accelerated by means of the angle of the cam as the tool enters the work. When the operation is completed a return cam on the forward drum shifts the lever and withdraws the cutter from the work, and a similar cam shifts the rear lever and the tool is drawn back ready for the next opera- tion. COUNTERSHAFT, MACHINE SIZES, ETC. The arrangement of the countershaft and driving belts is represented in Fig. 150. The machine illustrated will turn a length of 5 inches and swing 5 Fig. 1.50. — Countershaft and Drive for Prentice Automatic Turret Machine inches outside of the chuck jaws. The false jaws open 3j inches. The threading spindle receives shanks Ij^ inches diameter by 4^ inches long, and the other spindles have H x 3-inch holes. The threading capacity is up to f-inch pipe or H inches straight. There are three other sizes, the largest swinging 7 inches outside of chuck jaws, turning a length 154 PRENTICE MULTIPLE-SPINDLE AUTOMATIC TURRET MACHINE of 7 inches, and having a threading capacity for pipe up to 2 inches and straight work up to 4 inches diameter. DOUBLE-HEAD MULTIPLE-SPINDLE TURRET MACHINE As will be seen by referring to Fig. 151 this machine is built on very similar lines to the single-end machine by the same company, but is double- ended and, therefore, performs boring, facing, drilling, turning, threading, and other operations on both ends of a piece at one setting in the chuck. The standard machine has three spindles in each end, between which is Fig. loL — Prentice Six-Spindle Double-Head Automatic Turret Machine a chuck having four sections or sets of chuck jaws. The spindles, carry- ing the tools, are in line with the different sections of the chuck, except the upper section, where the operator removes finished work and inserts an unfinished piece while the machine operates constantly on a piece of w^ork in each of the other sections of the chuck. SPINDLE OPERATION The spindles revolve and are fed up to the work by means of yoke and lever connections with cams on drums inside of the bed, the cam shaft extending the entire length of the machine. The forward-feed cams are set at the proper angle to give the required advance or cutting feed to the tools on the work, and the reverse cams draw the tools back from the w^ork when the operations are completed. While the tools are backing off, the chuck is automatically indexing so that each piece of work is brought in line with the spindles which perform the succeeding operations. The movements of the machine are timed so that the indexing occurs GENERAL DATA I55 as soon as the longest single operation on any piece of work is completed. All the shorter operations are completed within this time, hence the time of finishing a piece of work on both ends is the time necessary for the longest single operation plus a few seconds taken in the indexing of the chuck and the advancing of the tools. THREADING MECHANISM As the chuck indexes toward the front of the machine, the first or roughing spindles are at the front, and the finishing and threading spindles follow. The threading mechanism consists of a sliding tap or die holder with a fork lever connecting with a cam to start the lead of the thread. The driving mechanism consists of forward and reverse friction pulleys with expanding rings. The tap is driven the required number of turns into the work, then the reverse is automatically engaged and the tap with- drawn. The proper cutting feed for different kinds of metal is obtained by change gears, a worm and worm gear connecting with the main feed shaft on which all cam drums are placed. The spindles are back-geared and have ample driving power for work within the rated capacit}^ of the machine. GENERAL DATA Three sizes of the six-spindle machines are built: One for light work, one with capacity for f-inch pipe size threads and smaller, and one for 2-inch down to f-inch pipe threads. The same design of machine is also built with four spindles in each head and a five-section chuck, the three sizes of this design corresponding in threading capacity with the three six-spindle machines. The eight-spindle type is adapted especially to handling bicycle hubs and gas and electric fixture work. All these ma- chines have the same chuck-steadying bracket as the single-head machine illustrated. SECTIOX II SCREW MACHINE TOOLS METHODS OF MAKING AND USING THEM CHAPTER XIX Points In Setting up and Operating Automatic Screw Machines In the following pages a few general suggestions are given which may be of interest to operators before considering in detail the different types of tools, determination of speeds, feeds, etc., treated fully in Chapters XX to XXVII. It should be borne in mind that the automatic screw machine neces- sarily has more complicated mechanism than a hand-operated machine, as many movements must be performed automatically, which in the hand type of machines are accomplished by the operator. The automatic machines must, therefore, have the more careful attention in setting up for turning out work. When, however, the machines are properly adjusted, very little attention over that recjuired on a hand machine is needed, although the use of dull tools must be particularly guarded against. The machines must be carefully erected and leveled up so as to avoid poor alinement between head spindle and turret, etc. operator's duties Ordinarily a workman will readily attend to six machines and on very simple straightforward work may economically look out for more. He should become thoroughly familiar with the machine operations and adjustments before putting in tools or starting up, and it is generally well first to operate the machine by hand before putting on power. Assuming that a new piece of work is to be produced on an automatic screw machine, it is well to consider first the various ways in which the work may be machined, and to give due consideration to the tool equip- ment available and to the quantity of pieces to be made, and then decide upon a satisfactory method. tools and collets The making of special tools and the changing of the camming of the machine (if any) must then be attended to. All tools and holders must be made accurately to give correct results, and in addition it is always advisable to check the first few pieces produced, by gages or otherwise, to see that the pieces are of the correct dimensions. The collet should grasp the rod the entire length of the bearing surface, and have a tendency 1.59 160 SETTING UP AND OPERATING AUTOMATIC SCREW MACHINES to bite harder on the front end than at the rear. This affords rigidity to the work when a cross-forming operation is being performed. The front end of the collet should likewise have a good bearing in its seat. The collet when closed must firmly grip the rod so as to prevent any slipping under the action of the cutting tools. HANDLING MATERIAL The feeding chuck must have sufficient grip to feed the rod accurately without undue marring of the material upon its return stroke. It is gen- erally considered well to straighten the bars of stock if they are bent, and also to gage them for diameter and to stack them into separate bundles if there is an appreciable variation which would cause difficulty when machining, and afterwards to make adjustment of the collets, etc., to suit the various sizes as worked up. Where different ciualities of steel are being used, extreme care must be taken to prevent mixing in a hard tool steel bar with the soft steel stock from which the work is supposed to be made; as the speed of the spindle and the feed may be such as to ruin expensive tools. TOOL AND OTHER ADJUSTMENTS It is, of course, obvious that the lubricating pump should be known to be properly working and all cutting tools properly set with regard to the work and their cutting edges properly ground in order to get good results. The head spindle bearings must be adjusted so as to permit running of the spindle at satisfactory speed without unreasonable freedom — else trouble will arise from this source. The cross slide, turret and turret- slide bearings uTust also be carefully adjusted and kept in good condition. The selection of the proper spindle speeds for various jobs, as well as the determining of satisfactory feeds should be considered carefully. In the next chapter are tables which should be helpful in this connection. PRODUCTION The rate of production is dependent not only on the rate of feed and spindle speed, but also on the tool equipment. The production of threaded work especially is facilitated by employing tools so designed as to take advantage of two speeds and to cut when the spindle is reversed. The camming should be such as to permit the performing of several operations simultaneously, such as drilling from the turret and forming from the cross slide. MANIPULATION OF TOOLS When changing the tool equipment from one piece to another the seat in the head spindle for the collet must be thoroughly cleaned as well as BELTS, OILING, ETC. 161 the collet, so as to avoid eccentricity in the operation of the rod due to foreign matter, when the stock is grasped by the collet. It is well before dismantling tools to make a model on the automatic screw machine for convenience in setting up in the future. This model should be complete in all respects, but should not be fully cut off to its usual length, but should be left intact, with sufficient length of the bar to tOiiP [ Fig. 152. "Setting L'p" Models for the Screw Machine permit grasping by the collet allowing the model to be the proper working distance from the end of the spindle. The illustration in Fig. 152 shows two models with the piece of stock by which they are held when setting up for the production of similar work. BELTS, OILING, ETC. It is recommended that belts without rivets be used for the spindle drive as they run smoothh' at high speed. Laced wire also makes a smoother running belt than where leather lacing or hooks are used for coupling the ends together. On machines where the belts are shifted to change a spindle speed or the direction of rotation, double belts will be found superior to single belts as the former being of stiffer cross section may be more quickl}" moved and the results desired more quickly obtained. The workmen in charge of machines should be instructed to lubricate all bearings frequently with good machinery oil and should be thoroughly familiar with the location of each hole and its function. Too much atten- tion cannot be given to this if satisfactory continuous service is to be expected from an automatic screw machine. The chapters that follow in this section describe in detail various classes of tools for screw machines and illustrate methods of making and using them. It is hoped that the information contained therein, with the chapters on camming and illustrations of tools in Section 1, may be of special interest and service to toolmakers, draftsmen and operators. CHAPTER XX Speeds and Feeds for Screw Machine Work The ordinary class of screw machine tools, suitable speeds and feeds for which have to be determined when camming automatics, includes the various turning tools such as box tools (adjustable and non-adjustable), hollow mills, drills, reamers, counterbores, taps and dies, forming and cutting-off tools. The accompanying tables of speed and feeds for differ- ent types of tools used on materials commonly worked in the automatic have been compiled from data accumulated and thoroughly tested during extended experience in this class of work and have proved of value in the screw machine department, not only in connection with the handling of automatics, but also, to a considerable extent, on hand machines, although, naturally, the matter of feeds on the latter class of apparatus is largely regulated by the personal equation; the question of spindle speeds, however, is quite as important and as readily settled for hand machines as for automatics. It is of course, impossible, where a series of tools is used on an auto- matic machine providing say two rates of speed for the spindle for any given job, to select speeds theoretically correct for each and every tool carried by the turret and cross slide. A compromise is necessary and therefore speeds are selected which will fall within the range suitable for the different tools; in determining these surface speeds and the rates at which to drive the spindle to approximate closely the desired surface velocities, the tables should be found of service. speeds and feeds for turning Tables 15 and 16 cover turning speeds and feeds for bright-drawn stock (screw stock) and brass, with various depths of chip (that is, stock removed on a side) from 3V inch up to f inch. These feeds and speeds and depths of cut are figured more especially for such tools as roughing boxes where the cut, though frequently heavy, is taken by a single cutting edge, the work being well supported behind the cutter during the opera- tion. Table 17 covers the same range of steel work as Table 15, but is laid out for hollow-mill operations; it will be noticed that, the cut being divided with this tool among three or more cutting edges, coarser rates of feed are provided for than with the box tool. With both classes of 162 SPEEDS AND FEEDS FOR TURNING 163 CUTTING SPEEDS AND FEEDS FOR SCREW STOCK. 3i 45 114 .006 2 40 76 .006 l>i 45 114 .006 154 45 98 .006 2^4. 40 68 .006 154 45 98 .006 2 40 76 .OOo 2M 40 61 .007 2 40 76 .007 234 40 68 .007 3 40 51 .007 2!4 40 68 .007 2>i 40 61 .007 3H 40 44 .oor 2>i 40 61 .007 3 40 51 .007 4 40 38 .008 3 40 51 j .007 33^ 40 44 .007 m 40 34 .008 Table 15. — Speeds and Feeds for Screw Machine Work 164 SPEEDS AND FEEDS FOR SCREW MACHINE ^VORK CUTTING SPEEDS AND FEEDS FOR BRASS y,2 Insh Chip X^ Inch Chip 'a Inch Chip Dia. of Stock Feet Surface Speed Kev. per Min. Feed per Kev. of Stock Feet Surface Speed Rev, per Min. Feed per Rev. Dia. of Stock Feet Surface Speed Rev. per Min. Feed per Rev. Vs 180 5500 .003 U 180 2748 .004 fi 165 1680 .004 Ke 180 3668 .004 h 180 1833 .005 X 165 1260 .006 K 180 2748 .005 H 180 1374 .0065 ?^ 165 840 .007 /» 180 1833 .006 ^■i. 165 840 .0075 1 150 573 .008 y^ 180 1374 .008 1 165 630 .0085 134 150 456 .009 K 180 915 .010 IX 165 504 .010 IX 135 342 .010 1 180 687 .011 IX 150 381 .012 154 135 294 .010 Ik. 180 549 .012 15.1 150 327 .012 2 120 228 .011 IX 150 254 .014 2 135 258 .014 234 120 204 .011 m 150 218 .014 23-4 135 228 .014 2k 120 183 .012 2 150 190 .015 2)4 135 204 .014 8 120 153 .012 2« 150 170 .015 3 135 171 .014 3X Jie Inch Chip 34 Inch Chip ?3 Inch Chip Dia. of Stock Feet Surface Speed Rev. per Min. Feed per Rev. Dia. of Stock Feet Surface Speed Rev. per Min. Feed per Rev. Dia. of Stock Feet Surface Speed Rev. per Min. Feed per Rev. }i 150 1146 .005 ?i 150 762 .005 ih 135 411 .007 vi. 150 762 .006 1 150 573 .006 IX 135 342 .008 1 150 673 .007 1¥ 135 411 .007 \% 135 294 .008 13i 135 411 .008 iH 135 342 .008 2 120 228 .009 \yi 135 342 .009 1?4 135 294 .008 23-4 120 204 .009 m 135 294 .009 2 120 228 .009 2X 120 183 .010 2 120 228 .010 2 k. 120 204 .009 3 120 153 .010 2h 120 204 .010 2X 120 183 .010 3X 120 131 .010 2% 120 183 .010 3 120 153 .010 4 120 114 .010 3 120 153 .010 3X 120 131 .010 4X 120 102 .010 Table 1G. — Speeds and Feeds for Screw Machine Work SPEEDS AND FEEDS FOR TURNING 165 SPEEDS AND FEEDS FOR HOLLOW MILLS. SCREW STOCK. 3:, Inch Chip Yg Inch Chip Ja' In Oil Chip Dia. of Stock Feet Surface Speed Rev. Feed per per Min. Rev. Dia. of Stock Feet Surface Speed Rev. per Min. Feed per Rev. Dia. of Stock Feet Surface Speed Rev. per Min Feed per Rev. ^B 80 2445 .0026 \ 60 916 .0045 U 55 560 .0052 ^16 70 1426 .0039 3j 60 611 .0052 H 55 420 .0065 H 70 1069 .0052 )4 60 458 .0035 % 55 280 .0078 li 70 713 .0065 J' 55 230 .0078 1 50 191 .0091 y. 60 458 .0078 1 55 210 .OOGl 1« 50 152 .0091 ■ii 60 3(j5 .0091 1'4 55 168 .0091 1>6 45 114 .0091 1 60 229 .0104 L^i 50 127 .0104 Hi 45 93 .0091 i'.t 60 183 .OlOi w 50 109 .0104 2 40 76 .0104 \)4 50 127 .0117 2 45 86 .0117 2>i 40 68 .0104 l?i 50 109 .013 2;^ 45 76 .0117 2}i 40 61 .0104 2 50 95 .013 2>^ 45 68 .0117 3 40 51 .0104 23-4: 50 85 .013 3 45 57 .0117 3>^ ! Ji's Inch Chip Ji Inch Chip ?8 Inch Chip Dia. of Stocli Feet Surface Speed Rev. per Min. Feed per Rev. Dia. of Stoclc Feet ' Rev. Surface per Speed Min. Feed per Rev. Dia. of Stock Feet Surface Speed Rev. per Min. Feed per Rev. Yz 55 420 .0052 X 50 254 .0052 1^4 45 137 .0065 3x 55 280 .0065 1 50 191 .003.5 \W 45 114 .0065 1 55 210 .0065 lii 45 137 .0066 IK 45 93 .0065 1¥ 50 152 .0078 \yi 45 114 .0078 2 40 76 .0078 l>i 50 127 .0078 i?i 45 93 .0078 234 40 68 .0078 1?4 50 109 .0078 2 40 76 .0078 2H 40 61 .0078 2 40 76 .0091 234 40 68 .0091 3 40 51 .0078 2M 40 68 .0091 2>i 40 61 .0091 2>^ 40 61 .0091 3 40 51 .0091 1 3 40 51 ! .0091 i ' ' Table 17. — Speeds and Feeds for Screw Machiue Work 166 SPEEDS AND FEEDS FOR SCREW MACHINE WORK tools the feeds are, of course, increased as the diameter of the stock increases, the peripheral speeds being reduced as the feeds grow coarser and the chip greater in depth. The speeds and feeds for finishing box tools as used on different mate- rials are given in Table 18, the last column indicating the amount of stock which, generally speaking, it is advisable to remove in order to pro- duce a good surface. CUTTING SPEEDS AND FEEDS FOR FINISH BOX TOOL •-3 Screw Stock Brass Rod Cast Iron Tool Steel Feet Surface Speed Rev. per Miu. Feed per Rev. Feet Surface Speed Rev. Ijer Miu. Feed per Rev. Feet Surface Speed Rev. per Mill. Feed per Rev. Feet Surface Speed Rev. per Min. Feed per Rev. >f6 80 4889 .003 180 11000 .003 40 2445 .002 .002 'A 80 2445 .0045 180 5500 .0045 40 1222 .003 .0025 5-16 70 1426 .0055 180 3668 .0055 70 1426 .0055 40 815 .003 .0025 « 65 993 .0075 180 2750 .0075 70 106t .0075 35 581 .004 .0045 % 60 458 .011 180 1375 .011 65 496 .011 35 267 .005 .006 X 60 305 .012 180 917 .012 65 331 .012 35 178 .007 .006 1 60 229 .012 175 668 .012 60 229 .014 30 115 .009 .0065 1>^ 55 140 .014 170 433 .014 60 153 .016 30 76 .009 .007 2 50 95 .014 170 325 .014 60 115 .016 30 57 .009 .008 Table 18. — Speeds and Feeds for Screw Machine Work FORMING-TOOL SPEEDS AND FEEDS Speeds and feeds for forming tools are given in Table 19, the widths covered here ranging from -^^ inch to 2 inches, and the smallest diameter of form from \\ inches down to xV inch. It will be seen that the tool about ^r inch wade is adapted to take the coarsest feed, tools from this width up to about fV (such as are commonly employed for cutting-off purposes) admitting of heavier crowding, as a rule, than either the nar- rower or wider tools. Thus we see the rate of feed drop off as the tool narrows to yV inch, which obviously is too thin a cutting device to admit of taking much of a chip, while similarly as the width of form and chip increases above about ^^ or \ inch the rate of feed must again be dimin- ished to give the best results. Naturally, other things being equal, the greater the diameter of the section formed, the coarser the feed which can be taken economically. This is also indicated by the figures in the table. DRILLING AND REAMING DATA Drilling speeds and feeds are given in Table 20. While these speeds are based on much higher peripheral velocities than drillmakers as a rule DRILLING AND REAMING DATA 167 recommend for general purposes, it should be remembered that conditions for drilling in the automatic on the usual run of work are nearly ideal so far as lubrication of drill and work, steadiness of feed, etc., are concerned, and it is possible under these conditions where the holes drilled as a rule are SPEEDS FOR FORMING Dla. of Work Screw Stock Brass Rod Cast Iron Tool Steel Feet Surface Speed Rev. per Min. Feet Surface Speed Kev. per Min, Feet Surface Speed Rev, per Min. Feet Surface Speed Rev. per Min, H 75 2292 200 6112 H^ 75 1528 200 4074 '4 70 1063 185 2827 75 1146 45 688 % 65 662 185 1885 70 713 40 407 H C5 497 185 1414 70 535 40 306 K 60 305 175 882 65 331 35 178 1 60 229 175 667 65 248 35 134 1>6 60 153 170 432 60 153 30 76 o 50 96 170 324 60 115 30 57 FEEDS FOR FORMING TOOLS With of Form SmaUest Diameter of Form. '4 -16 M X y^ X 1)4 '-16 .0007 .0008 .001 .0012 .0012 ,0012 ,0012 ,0012 li .0005 .0008 .001 .0012 .0015 .0020 .0025 .0025 H .0007 .001 .001 ,0015 ,0015 .0018 .0018 ?3 .0009 .001 ,001 .0012 .0015 .0015 }i .0008 .0009 .001 ,001 .0015 .0015 X .0008 .0009 .001 .0011 .0012 1 .0008 .0009 .001 ,0012 \>i .0007 .0007 ,0009 ,0011 2 .0007 .001 Table 19. — Speeds and Feeds for Screw Machine Work comparatively shallow and the drill has ample opportunity for cooling dur- ing the operations carried on by the other tools, to maintain speeds that would be considered too high to be attempted in general shop practice. Table 21 is made up of speed and feed data for reamers. In this table 168 SPEEDS AND FEEDS FOR SCREW MACHINE WORK •— I— it,"\ea5'n'"^*'CEJuu w Q Ph m Q xn Q ft o o K.P.M. at 33 Ft. Peri- pheral Speed 8 g CO 2 *31 CO £ s 2 g s CO g CO no 1^ s t- CO CD 1 C5 3 CO CD O CO i 1 o o i o i cs 2 p o cS O 0- 'nA^'g^cn 1 i ^5 i 8 i o Si g <:» 1 2 1 00 OS CO OS 1^ o 3 1 c:5 t:- s s 8 8 O CD CD CD g CO i o o CD CI p CO p p o 01 7! 1 to s o 53 o 3 g i CO CO in 1 CO 1 t- ^ 3 |i( -^ M i ^ t* t- 8 8 i 1 o CO o CO o p CO p CO in p s p 2 p o M CD O m i Si CO i i i O SI Ol s ca 05 CO 2 05 CO Ol 00 2 ^ fe - « i. CO 1 8 i. CD i 00 1 8 i CD o CD p CO p •* p 5°5 :.^ ;t /^ i= -2 .- v2 ^? -2 - a." 5 S 2 S H (M (D m o o oj CM CO i i 1 i CO CO 8 s -* i s i c:^ i o o CD 8 o CD lO i i • CO 8 CO 8 o o i i t- o CO ^ S ^ t- i 5; 2 00 00 ■» C>J 00 3 CO c^ 00 S f^ °' « <3 o o C3 CO o CO 8 o CD 1 lO i i 8 3 CD iCI 3 CD 3 CD lO 3 p o IS o CO fc ^ JO S o S, o CO 1 1 o c» i 00 CO iCI 1 ot t- 1 1 i 00 CO o o 8 1 co CO CO i 8 CD 8 1 i 00 8 p p o o o • « En L, " (B i- o 88 -7* 35 t- i in 2 CO 2 00 c:^ 1 00 o i CO i Is £ fe ^ M CD i 8 CO 8 «o 00 s 8 ;v:T,r,r,r7;;iri,T. -1 y' ^'|i.i"i'D'!i''j'i'i;'', 1 J te- rx V 178 BOX TOOLS AND OTHER EXTERNAL CUTTING APPLL\NCES used mostly for brass and similar material and for light cuts on steel, and is in this general form commonly known as a finishing box. On very free-cutting materials such as brass, the edge of the cutting tool is generally presented to the work without any rake, as shown in Fig. 163. In cut- ting the harder materials, steel, etc., and especially in taking roughing cuts on such material, rake is desirable; hence the tool of the roughing box is presented to the work in the manner shown by Fig. 161. The tangent cutter used in the box tool shown in this view and in Fig. 160 is sharpened by grinding on the end, and compensation for the grinding away of the metal is made by adjusting the cutter forward, whereas in the radial type of cutter in Figs. 162 and 163, frequent sharpen- ing cannot be done without resulting in lowering the cutting edge of the tool below the center of the work, unless a substantial part of the tool be sacrificed. The radial tool, however, is easily ground accurately on face a, which is the particular edge governing the finish; while the corre- sponding face on the tangent type of tool is rather difficult to grind so as to produce as smooth work. OTHER FORMS OF BOX TOOLS Fig. 164 outlines the general scheme of a box tool with tangent cutter having means of radial adjustment for various diameters, the back rests being adjustable also, as indicated. In Fig. 165 we have a box tool with a back rest of the bushing type Fig. 16.5. — Bushing; Box Tool which fully envelops the work. A bushing like that shown in Fig. 166 is frequently used in the bushing type of box tool. This bushing is tapered externally and drawn into a conical hole, and is thus suitable for slight variations in stock sizes. Fig. 167 shows another "solid" rest, but with- out a bushing. The question of chip room frequently makes it neces- sary to abandon the bushing and bore the hole for the stock directly in the back rest. Quite often the back rest is cut away to allow the tools to operate on a second shoulder cut; then the bushing as ordinarily made interferes. As a rule, it is preferable to use the bushing where possible, owing to the ease with which it may be replaced when worn out of shape, SELECTION OF BACK RESTS 179 and also because of the facility with which anv chano;es due to hardenino- may be corrected. Other types of work-supporting devices, such as internal stem rests, etc., are very commonly used. Fig. 168 illustrates such a combination. Frequently, too, revolving stem rests are used in place of the stationary type shown. Quite often a drill or counterbore is held in the shank of the box tool in a similar manner and acts as a support, and also, as before stated, enables turning and boring operations to be accomplished simul- taneously. FIG. 169. Long Work FIG. I 66. Bushing d 1 — ^-^■ b tdB FIG. 167 Work :q ^^■^^^■^-^ __-.\ i ¥ 1 k i V rr-" . i 1 '^ ' u ) Shank FIG. 168 Other Turning Methods SELECTION OF BACK RESTS Generally speaking, work that projects over one and one-half times its diameter from the spindle chuck cannot be turned accurately or rapidly without the aid of a support which will prevent the work springing away from its proper radial relation to the edge of the cutting tool. Usually on work which does not project over five diameters from the chuck, the back rest is located so as to support the work by the diam- eter produced by the first cutting tool in the box tool, the back rest being set from about -g\ inch to ^V ii^ch back of the cutting tool, as in Figs. 161 and 16.3. While any of the types of back rests shown in Figs. 160 to 167 may be used, on w^ork of the length mentioned an enveloping back rest is not required. The type of back rest used in the tool in Figs. 162 and 163 is adjustable for wear and preferable on this account. The non- adjustable open back-rest, Figs. 160 and 161, is recommended only when the design of the tool makes it difficult to utilize an adjustable type. All back rests should be of tool steel. They should be very hard and smooth; otherwise when used on fast-running material such as brass, a welding action takes place. They should be ground and lapped on the bearing face so as to bear more strongly on the forward end of the work than at 180 BOX TOOLS AND OTHER EXTERNAL CUTTING APPLIANCES the rear. The clearance need not be more than 0.003 or 0.004 inch to the foot. Should the back rest be bell mouth, the work turned will be rough and covered with ridges. TOOL POSITION, LUBRICATION, ETC. Also it is quite important, where using such rests, that the work be not turned too large if roughing up of the surface is to be avoided. About 0.0005 inch freedom should be allowed for work up to ^-inch diameter, and about 0.001 inch freedom for 1-inch diameter. Proper lubrication of the bearing is also essential in preventing roughing up of the work. Lack of alinement of solid or half-open rests with the spindle of the machine may also cause the production of poor surfaces on the work, owing to the heavy crowding action under such conditions. In setting adjustable back-rest jaws it will be found conducive to good work to hold a bar in the head spindle, turn a true running piece of work from 0.0004 inch to 0.0008 inch oversize and then adjust the jaws so that they will bear snugly on the turned part. The closer this is to the spindle the better. In using solid or non-adjustable open-back rests, as shown by Figs. 160, 161, 165, and 167, it is recommended that they be bored out while held in the turret hole of the machine that they are to be used in. This insures the hole being in alinement with the head spindle; these conditions, as well as having the turret slide travel parallel with the axis of the head spindle, are necessary in order to produce accurate work. Burnishing of stock generally results from the pressure of the cutting tool forcing the work against a closely adjusted, smooth back rest, and is usually considered an evidence of proper adjustment. Frequently, how- ever, this is found not to be the case. LONG AND SHORT W'ORK On very long w^ork, when bright-drawn cylindrical stock of uniform diameter is being turned, the solid back rest is found very satisfactory. The rest is in this event set ahead of the cutting tool and fully enveloping the work. It obviously prevents any tendency for the work to spring away. Where heavy stock which does not run true is to he machined, it is necessary before turning partly to cut off, as shown by Fig. 169, thus permitting the back rest to pull the bar into central position. In case there are short bends in the bar, trouble will be met, so that for long work machined in this manner it is necessary to select straight bars. It is also important where a back rest is used ahead of the cutting tool (that is, where the unmachined bar rotates directly in the back rest) to select practically uniform diameters of stock, not varying in size over 0.0004 inch to 0.0008 inch. In many large screw factories all bright-drawn stock is carefully gaged as soon as received and sorted out in this manner; CAST-IRON WORK 181 in setting up the machine a back rest is selected to suit a particular bundle of gaged stock. IRREGULARITY OF STOCK SECTION Where bright-drawn stock is used which is slightly out of round, as is very frequently the case, the use of a full enveloping back rest preced- ing the cutting tool will be found superior to the jaw type, giving a two- point bearing. In the former case the pressure of the tool cannot force the work away and the turned part will be cylindrical; whereas with the jaw type of back rest the pressure of the cut will keep the irregular con- tour of the bar against a jaw and consequently reproduce a similar cross- section to the turned part. This emphasizes the value of using back-rest jaws so as to follow the cutting tool; but as before noted, their use is lim- ited to short work and work of medium length. In such work, if the back- rest jaws are properly set and the turret slide travels parallel with the axis of the head spindle, true work will result irrespective of the collet or turret hole being out of line with the spindle. CAST-IRON WORK In machining cast iron, as on the magazine automatic, box tools with the ordinary types of rests are not satisfactory, owing to the fact that the cast-iron dust is apt to l^ecome ground between the rest jaws and the turned part of the work, thus causing the latter to become roughed up. The use of water, however (with just enough oil to prevent rusting), or any thin solution under pump pressure, effectually overcomes this trouble; oil seems to increase the difficultv. ^ ^ ^^^g^sl fe^ ^w^2^^ S'«l ^^ p^ Fig. 170. — Box Tool with Roller Rest A box tool with roller back rests, which is excellent on cast-iron work when used in conjunction with an air blast to keep dust from accumulating between the rollers and work surface, is shown in Fig. 170. This box 182 BOX TOOLS AND OTHER EXTERNAL CUTTING APPLIANCES tool as sometimes used on the Pratt & Whitney magazine machine, may- be stiffly supported at the bottom by a hardened-steel plate carried on a bracket attached to the front end of the turret slide and traveling with the slide. Another satisfactory way of turning cast iron is by means of hollow mills. HOLLOW MILLS Hollow mills are also very suitable for turning long work from bar stock. These tools with multiple teeth support the work centrally, cut very rapidly, and if held concentric with the head spindle and properly cleared will produce excellent results. Fig. 17L — Hollow Mills and Clamp Collar Fig. 171 illustrates a form of hollow mill. The clamp collar shown in the group is commonly used for slightly adjusting the teeth to cut to correct diameter. Another good form of clamp ring is shown in Fig. 172. , Taper = M per Foot ; Finishing } ( Roughing -* Ke ?& % y.-r. % 'A-2 K '%! Ke % K % X D= .072 .104 .135 .106 .197 .229 .20 .291 .322 .385 .510 .635 .700 L = K M % y^. % % Vm '4, M % % % 1 •"• 10 ~ .006 .009 .012 .015 .019 .022 .025 .028 .031 .038 .050 .063 .075 I = % rm y^, Jfe Mo % % % % % Vi, 13/ /l6 O = % % % % % % % % % 1 m 1% 1% FIG. 173 Clamp-Collar and Hollow-Mill Dimensions This is made with sufficient metal at one side to admit the clamping screw, while the opposite side of the ring is weak enough to allow it to close properly upon the mill when adjusted by tlie screw. TAPEK-TrRMXd TOOL 183 The tcoth (»f hollow mills should he r:i^s work, etc., but on harder materials, such as steel, which is more destructive to the 187 188 DRILLS, COUNTERBORES AND OTHER INTERNAL CUTTING TOOLS cutting edges and thus makes frequent regrinding necessaiy, a tool holder havmg separate starting and facing cutters, as shown in Fig. 186, is pref- erable, as the independent adjustments allow frequent sharpening to be more economically accomplished. FIG. 189 Clearance on Periphery of Drills Clearance on Periphery of Couuterbores Spotting Tools and Drills FIG. 191 TWIST AND STRAIGHT FLUTE DRILLS In drilling cylindrical holes standard commercial tools are preferred owing to the convenience of replacement when they become worn out or broken. Ordinary twist drills are very satisfactory in steel and cast iron, although in very deep holes the chips are sometimes difficult to get rid of, and clogging up of the flutes and occasional breakage will then occur unless frequent withdrawing of the drill is resorted to. On brass and all free cutting stock the rake given to the cutting edges of twist drills generally causes excessive curl to the chips and thus makes the automatic removal of the chips from the hole difficult. On automatic screw machines oftentimes a long curled chip is very objectionable as some machine functions may be interfered with. For these reasons, BACK AM) LAM) ("MCARANCES ISO when twist diilLs arc used in brass, it is gooil practice to reduce this rake by grinding in the Ups at tlie front end, as in Fig. 1X7. A two-lip, straight-fluted drill commonly known as a " I'arnier" drill is generally superior to the twist drill in cases where tlie curling of the chips is troublesome, and in shops where bra.ss work predominates, this drill is used nmch more connnonly than the twist drill. SEKHATEl), FLUTKI) AM) STKl'I'KI) LII'.S The cutting edges of drills are sometimes serrated as indicated in Fig. 1S8 to produce narrower ciiips than would otherwise result and facilitate their easy removal. A similar effect is produced by fluting the ihill, as shown by Fig. ISO. Still another method of producing narrow chips is to step the end of the drill. It may be of interest to mention that this latter scheme is very connnonly u.sed in the one-lip drills for drilling long holes in gun barrels, spindles, etc. Fig. 100 will give an idea of this type of tool. When such a drill is carefully guided and advanced at a low rate of feed it is possible to drill a distance of 30 or 40 inches with not more than 0.010 inch curvature in the length of the hole. There is no center web to prevent free cutting as in the two-lip twist drill, and oil is forced under pressure to keep the cutting cool and conduct away chips. The use of oil in this manner is found very effective with all classes of internal cutting tools, except when operating in cast iron. It makes possible the runnmg of work at a high peripheral speed without excessive heat, results in rapid cutting and insures long life to the cutting edges of the tool. The center edge of all twist- and straight-flute drills should be thinned down at the cutting point, as the drill will then cut more freely and less power be re<[uired for the work. BACK AM) LAM) CLEARAN'CES Drills .should have some back clearance, from 0.007 to O.Olo inch per foot being common practice. The land back of the cutting edge should be quite narrow as little land is required to support the drill and prevent chattering, while an excessive width increases friction and heat, resulting in the welding of chips to the drill along these surfaces ami the conse- quent production of rough holes of varying diameter. Fig. 101 repre- sents the manner in which drills and counterbores should be cleared on their peripheries. The milling cutters used to flute twist and other drills should be of such form as to produce a straight cutting etlge on the drill. If there is a curve to the cutting edge curved chips are produced which are diffi- cult to bend or curl and such chips not only cause exces.sive heat, but severe strain on the cutting tool and fri'cpient breakage of the latter. 190 DRILLS, COUNTERBORES AND OTHER INTERNAL CUTTING TOOLS The various steps on short internal cyUndrical cutting tools should be tapered back about 0.020 inch per foot, and the peripheral contact reduced to a minimum so as to give ample chip clearance and avoid weld- ing of chips. FLAT DRILLS AND COUNTERBORES Fig. 192 illustrates a type of tool commonly termed a flat drill, which is extensively used on brass work; it is especially recommended for such material where there are numerous shoulders or forms to be cut out. The tool has a cylindrical shank which fits a turret tool holder. On large work it is customaiy to make the flat drill of rectangular stock and util- ize a special holder, as shown in Fig. 193. FIG. 196 Flat Drills and Counterbores FIG. 197 Such tools when held in the turret, as in Fig. 194, should be placed with the faces vertical so as to prevent them from cutting appreciably ■oversize if the indexing of the turret, due to wear, is not perfect. In the event of the turret holes after long usage being badly out of line, an adjustable holder should be used. A tool of this character is illustrated in Fig. 195. A one-lip drill or counterbore with a heUcal cut, as represented in Fig. 196, is found superior in many cases as it permits of grinding the cutting edge without changing the form of the hole produced. MArniXE REAMERS 191 Countcrboros as well as drills slunilil have sufficient back and peripheral clearance but should nut have too many cutting lips. A back clearance of about 0.020 inch per foot is satisfactor}-. For counteiboics up to 1 inch three flutes or cutting lips are ample; moie flutes are apt to result in insufficient chip space. STEPPED COUXTERBORE.S In making stepped counterbores where chips bother, it is conducive to good results to provitle only one cutting edge for each step and to have successive cutting edges arranged spirally on adjacent cutting lips. Fig. 11)7 illustrates a stepped counterbore for rougiiing a hole that is afterward to be finished by a taper reamer. The advantage of this stepped counterbore lies in its producing a hole with a number of slight steps without an undesirable quantity of chips to wedge antl cause trouble. For brass work the flutes of counterbores should generally be parallel with the body of the tool, while on steel the flutes should be cut so as to give a positive rake angle of 10 to 1.5 degrees; the deeper the hole to be countcrbored the less the angle of the tool. For steel, and particularly in deep holes, internally lubricated counterbores are effective in keeping the edges cool and in forcing out chips. The various effects produced by counterbores with their cutting edges ahead or behind center, tiie value of proper rake and lubricants, are discussed in Chapter XX\'1I un cling- ing of chips to screw machine tools. MACHINE REAMERS Machine reamers are generally used for finishing holes smoothly and to size, and consequently it is advisable not to leave too much stock for these tools to remove. On steel work from | to 1 inch in diameter, from 0.004 to O.OOS inch is generally satisfactory, while in brass from 0.00() to 0.012 is a suitable amount. It is well to have the teeth of all reameis unevenly spaced, as there is then less liability of chattering than where even spacing is adopted. Cylindrical reamers should only cut on the front end in entering a hole; they cut back of the front end, on the Ups, only when the material being reamed alternately expands and contracts through undue pressure or variation in temperature protluced by the cutting action. This latter is particularly noticeable in brass tubing. .Most cylindrical reaming tools like Fig. 19S are cleared the entire length of their cutting lips as well as having a back taper of about 0.004 inch per foot. For reaming steel where it is desired to produce an accurate smooth hole the so-termed rose reamer, Fig. 199, is excellent. This tool can cut only on the front end, and must be well lubricated and not forced so as to expand the work. It will ream holes under these conditions that are satisfactorv to the 192 DRILLS, COUNTERBORES AND OTHER INTERNAL CUTTING TOOLS most exacting. For this work a rose reamer is better than a reamer with peripheral clearance, as its weight is more satisfactorily supported and there is thus more certainty of a round hole being reamed. A rose reamer, as intimated, has no peripheral clearance on the flutes, but should be back-tapered about 0.00-i inch per foot. FIG. 199 One Cutting Lip only -» U.About H2 Two Back Eest or Supporting Lips Reamers and Reamer Holder THE CUTTING EDGES The cutting edges of reamers are seldom undercut and are generally on center, although for brass it is considered by many advisable to mill the cutting edge ahead of center and so secure a scraping cut. The flutes are generally milled parallel with the body of the reamer, but in many cases a spiral-fluted reamer has been the means of obviating chattering. The spiral should be cut left-hand to prevent drawing in. In small work, particularly brass, a flat reamer like Fig. 200 gives good results. It is inexpensive to make, and may be readily re-sharpened as indicated. Reamers or, more correcth', boring tools with three flutes and with only one cvitting edge as shown by Fig. 201 are found veiy useful for producing straight, deep holes. REAMER HOLDERS Usually reamers for cylindrical holes (and sometimes finish counter- boring tools) are carried in holders permitting of a floating action of the reamer. When a reamer is held rigidly in the turret hole there is almost a certainty of its cutting an oversize and tapering hole clue to the im- practicability of retaining the turret hole in perfect alinement with the work spindle. There are a variety of floating reamer holders used. A simple form is illustrated in Fig. 202. With a reamer held in a suitable floating holder and providing the end of the hole that is to be reamed RECESSING TOOLS 193 has been Ijorcd out so us to run true, and from 0.003 to O.Olo untlorsize, there sliould be produced a lioh' true to size and concentric. NIMHKK OF FLUTES I.\ KEAMEKS The number of Ikites cut in (ordinary reamers should \)v as indicated by the following table: Hand. Fluted Chucking. i to /j diameter 4 flutes. i to ^~s diameter G flute.s. \ to ', J diameter 6 flutes. i to IJ diameter 8 flutes. i to 1} diameter 8 flute.s. lA to IJJ diameter 10 flutes. 1/j to Ijl diameter 10 flutes. If to 2, "a diameter 12 flutes. If to 'ij", diameter 12 flutes. 2i to 2 J diameter 14 flutes. 2 J to 2 J diameter 14 flute.5. 2,*« to 3 diameter 10 flutes. 2JI to 3 diameter 16 flutes. T.\PER RE.\MERS Taper or formed reamers should be provided with clearance the entire length of their cutting lips. The lips or huuls instead of being continu- ous are in the case of long reamers usually serrated by means of a narrow left-hand spiral groove, and this breaks up the chip into a number of curled strips instead of producing a single wide one. The flutes in taper reamers arc sometimes milled left-hand so as to prevent pulling in, and sometimes right-hand to assist in cutting. On slight tapers any tentlency to draw in must be obviated owing to the risk of breaking the tool, while on steep tapers which resist the feeding in of a tool an opposite effect is desired. In practice, therefore, it is found satisfactoiy from the cutting point of view, to make the flutes left-hand in reamers producing holes tapering from to about 1^ inch per foot. From U to 21^ inches taper per foot the flutes may be straight, while on tapers greater than tiiis a right-hand flute is satisfactoiy. This latter gives a positive rake to the cutting edge, and less end pressure is rccjuired to force the tool to the cut than with straight or left-hanil (lutes. The cost of nuiking tools with right- or left-hand llutes is somewhat greater than for straight flutes, and grintling is not so readily accom- plished with ordinaiy equipment, hence straight-flute taper reamers are more commonly u.sed. RECESSING TOOLS Recessing tools constitute still another class of internal cutting appli- ances used on screw machine work for forming grooves and chambers in pieces after they have been drilled or bored out as required. There are 194 DRILLS, COUNTERBORES AND OTHER INTERNAL CUTTING TOOLS many types of recessing appliances, and one is illustrated in Fig. 203. The body A has a shank fitting the turret hole, and carries a stud upon which is pivoted the tool holder B in which is inserted the cutting tool. This swinging member B is held normally in central position by loop spring C. In operation, after the tool has entered the hole in the work to the required point the cross slide advances, and, acting upon adjusting screw Make to suit Work Fig. 203. — Recessing Tool D, presses the holder B toward the rear and causes the tool to cut the internal channel in the work. If a chamber or recess of some length is to be formed, the turret slide then advances and the tool takes a boring cut along the side of the hole. Upon completing its work, the tool is relieved by the cross slide receding, and is returned to central position by spring C which presses the pivoted tool holder B forward until a stop plug E contacts with stop pin F in the shank. The turret then withdraws the tool from the work. CIIAI'TIIK XXI\' SCUKW Ma< IIINK TaI'S AM) DiES Taps and dies form ii vcr\- iiitcrosting topic I'nr discussion anionji tool- makers, and as the conditions under which they are used have quite a bearinji on their correct desi<>:n. it is the case that iileas as to their specific dcsiiiu are greatly at variance. Possibly the selection of the steel used and the manner in which the hardening is accomplished have a more important bearing on results than in the case of any other class of cut- ting tools. This chapter is not intended to cover this phase of the subject, but it nuiy be opportune to state that in our experience it has been found best from an economical standpoint to temper a tap quite a little lower than a die. E.xceedingly hard, brittle taps aie liable to fre- quent breakage on account of their relatively weak cross-section and small chip space as compared with a die. Keeping taps sharp is more economical than continually making new ones to replace those breaking on account of being unduly hard. A die, however, may be so designeil as to have ample metal for strength and much more chip room than the tap, and consecjuently breakage from this cause is not so liabh* to occur as with the tap. Furthermore, re-grinding of a die is considered more difHcult than re-grintling a tap, and therefore the die is generally left harder than the tap. The speed of work while external threading operations are performed may l)e higher than for in- ternal threading on account of the foregoing rea.sons and also becau.se of gi-eater facility for properly lul)ricating. Tables of speeds for dies and suggestions on lubiicating are given in ('hai)teis XX and XX\T1. TYPES OF DIES AND TAPS Fig. 204 represents what is commonly known as a spring screw-thread- ing die, with its clamping or size adjusting ring, and Fig. 205 a button die. Both of these tools are used extc^nsively in the automatic screw machine. On large work dies with inserted chasers, one form of which is shown in Fig. 2(K). are found very satisfactory. \'arious types of open- ing dies are also being successfully u.sed on different cla.sses of work. Taps are generally made solitl, although there is doubtless economy in the inserted blade type of tap when of large dimensions. Collapsing taps are also made for some lines of work. 195 196 SCREW MACHINE TAPS AND DIES Fic. 204. — Spring-Screw Threading Dies Fig. 20."). — Button Dies til Fig. 206. — P. A: ^Y. Inserted Chaser Die SPRING DIE.S Owing to the movable parts which may affect perfect ahnement be- tween the turret hole and the head spindle of turret machines, it is found impracticable to hold dies or taps, even if perfectly true and concentric, directly in a turret hole or in a rigid non-adjusting tool holder. Ordinary- commercial spring screw-threading dies, even when mounted in holders permitting of side play, are apt to produce better results if made with three cutting edges, as in Fig. 207, than if provided wath four or more cutting edges. With the latter, the result due to changes in hardening SPRING DIES 197 or imperfect workmanship is apt to be that only two diametrically oppo- site teeth are sinuiltaneously cuttinp;, as shown in Fis;. 20S. This causes the die to vibrate and produce a rough thread, with chatter marks, ^^■ith commercial dies having three cutting edges and providing that they are mounted in a free holder these troubles are greatly reduced. On one FIG. 207 FIG. 208 FIG. 210 FIG. 211 FIG. 209 Dip 111 Lt to Ik aa Pot >re AAA/V^ Ay^ \\ "\ FIG. 21. FIG. 213 FIG. 214 Spring Dies occa.sion, in the designing and tooling of 70 turret machines for a foreign order, about half of which machines were automatics, it was decided to make all of the .spring screw-threading dies with three teeth only. The diameters of work to be threailed were from 3 millimeters (approximately I inch) to 32 millimeters (appro.ximately l\ inches) and the threads per inch, with the excejition of the large sizes, somewhat less in number than United States standartl. The parts to be machined were of low-carbon tool steel, cold drawn machineiy steel, brass, and also some copper. 198 SCREW MACHINE TAPS AND DIES Excellent results were obtained in hardening, and onh' three dies were cracked or ruined by the fire. There was not a single die ivhich gave any trouble whatsoever when setting up and testing the equipment. This record would have been impossible with four-tooth dies. TAPPING OUT THE DIE It is good practice in making spring screw dies to either hob out the thread with a hob tap 0.005 to 0.015 inch oversize, according to size, and in use to spring the prongs to proper cutting size by a clamping ring as shown in Fig. 204, or to tap the die out from the rear with a hob tap tapering from ^^ inch to \ inch per foot, leaving the front end about 0.002 inch over cutting size, and in this case also to use a clamping ring, Fig. 204. Both of these schemes are for the purpose of obtaining back clear- ance and are effective. Theoretically, the use of the taper hob is the best, and is to be preferred especially when work is to be cut with threads of included angle less than 40 degrees, as the shape of thread produced by clamping the prongs of the die to a size below that at which it is hobbed may then be affected enough to be decidedly unsatisfactory. Fig. 209 illustrates this bad feature. Fig. 210 illustrates the die with the taper somewhat exaggerated, as made with a taper hob and the general internal form of a very satisfactory spring screw-threading die. HARDENING In hardening a die it frequently happens that curves to the lips are produced as in Fig. 211. When clamping the prongs of an oversized hobbed die (with such curvature) down to size, this will still result in a bell mouth die. , With a die hobbed out with a tap of sufficent back taper, as in Fig. 210, the curve, if it exists, will not result in a bell mouth; the clearance angle being more pronounced than with an oversize tapped die, neutralizes the curvature. The internal form shown by full lines in Fig. 212 is bad, as the thickness of metal varies so that in hardening trouble will result. In Fig. 210, and as shown by dotted lines in Fig. 212, is a more satisfactory internal form. Probably the best practice in hardening is to dip the prongs into the lead pot not further than dotted lines W-X, Fig. 213, in which case less trouble will result, and the heat will still be sufficient to cause the remain- ing portion of the prongs to be sufficiently hard when chilled, to prevent welding of chips, etc. In case the hardening effect extends back into the curve as at Y-Z, side-twisting of the prongs is almost a certainty, and the cutting edge of the die in this event will not be in contact with the work, but a portion back of the cutting edge will be dragging on the work which will cause a ragged thread and oftentimes break off the piece being threaded. crmxr; KDf.Es 199 In spite of faro tlicrc is imicli risk in the length of the prongs being at vuriunc'c after liar(U'nin<>vV^V- K^ -o.-.-.^.-.v- ^.y//////- 1 FIG. 21S Button Dies This type of die, on account of the chance it affords for what would ordinarily be consiilered an excessive rake without springing, is found very sati.sfactoiy for cutting copper. In the button die, as shown in Fig. 215 and Fig. 21S, it should be noted that the expantling wedge is a taper pin which acts as a tie and 202 SCREW MACHINE TAPS AND DIES prevents a twist to the tlic which might occur from hardening if a wedge were used as in Fig. 216. The Une a, Fig. 215, representing the cutting edge of the die, may be pointed on center or above, as desired, and then the center of hole h is located on line c so that the edge of the hole is tan- gent to the line a. APPLICATION OF DIE TO WORK Most dies are chamfered, so as to cut smoothly and to assist in start- ing on to the work, as in Fig. 218, but it sometimes is necessary to cut very closely to a shoulder with one die only, and in this event there can FIG. 219 Forming Tool FIG. 220 Threading Work be but little chamfer. It will be of assistance in starting the die under these conditions, when work permits, to bevel the end of the work as indi- cated in Fig. 219, prior to running the die on, and afterward remove the bevel at a, if objectionable. It sometimes happens that very short threads have to be produced, as shown at .4, Fig. 220. An effective method of producing such work is to first cut a long thread and afterward face off the extra portion LENCIII AM) M .\II{i;i{ OF LANDS 203 betwoon nock />' ami the end of tlu^ j)i( co. The nicking at B, provi(|uently reversed, thus break- ing up the mass of chips, the thread will either be mutilated or the tap broken. It will be seen upon examination of Fig. 222 that only one side of the thread that is being formed with the tap there shown is operated upon at once. It is thus relieved of one-half the pressure and wholly of the wedging action, and because of the ab.sencc of the next adjacent threads, a slightly lateral movement of the thread being formed is possii)le, owing to the mobility of the metal. It is probable that under similar comli- tions the removal of alternate teeth in a die would be of value. LENGTH AND XIMHKK OI' LAXHS The number of teeth in regular taps and wi<) 7 0.(M)4.5 0.00U5 6 0.00.5 0.010 STRING DIE SIZES It may be of value to include a table of suital)le dimensions for spring screw dies, and the data in the sketch, Fig. 226, should prove of service, 206 SCREW MACHINE TAPS AND DIES particularly for steel. For brass the cutting edge is radial, thus eliminat- ing dimension A. The width of land at bottom of thread is usually Taper of Tap = }^ per ft . D = '•16 ?5 ^16 H '-ia *3 ■*! *o **3 *10 *12 Th'ds P.I. = Oi 4U 32 20 18 50 40 ■a ^'32 ==^32 'H^ A ^ Ji- .0J3 .0,2 .019 .025 .031 .010 .oil .oil .013 .019 .021 L = ' 16 ^i2 % ••. H ' 32 H " 32 = 13 'Hz K D = % to ii H to H % to 1 Th'ds P.I.= Std. Std. Std. A = D -J- 10 D -h 10 D -^ 10 L = ^ 1" l'^ O.S.Dii. 1" 1?3 1% LeugtU 2" 2Uj" ili" Fig. 226. — Spring Die Dimensions made about { 0. D. of cut, the milling between flutes being 70 degrees for the flute and 50 degrees for the prong in the case of three-flute dies. SIZING DIES AND TAPS As most all dies have means for slight adjustment, it is not necessary to use the same care in sizing them as in the case of taps which are gen- erally non-adjustable. Dies may be "chased out" to fit a male-threaded plug and a tap to suit a female gsge. In the event of having only a plug or a sample to work to, the ball-point micrometer is very convenient in comparing dian^eters when cutting the thread on a tap. In making taps to a drawing or specification, it is of assistance to turn a portion of the tap to the theoretical bottom of the thread and then with properly formed threading tools, to use this part as a gage when sizing the tap, either copper plating with blue vitriol and burnishing the plate with the thread tool or dispensing with the plating and using a good eye-glass to detect when actual contact between the threading tool and tap blank at gage- point takes place. TESTING THREADING ACTION When in doubt as to the proper cutting action of a die or tap it is advisable to carefully turn or bore a piece of work, then thread the work under normal conditions, but to stop the work with the cutting action taking place, then in the case of external threading, note whether all the cutting edges are producing an even clean chip, or pushing the thread off. In case the thread in the die is smooth and the cutting edges are sharp and have been properly lubricated and the work is poor, the chances are that the angle of rake or the clearance is at fault. ADJUSTMKXT TOR J.l.N'iTH ( •! TllliliAI) 207 To examine the hole tapped out tlie work must be carefully sawt-il into two pieces. 1)1 1; HOLUEUS Holders for die and taps for the automatic have much to do with the success of these tools. Fig. 227 shows a very satisfactory holder made by the Pratt & Whitney Company. This ajjpliance was developed for u.se in a screw machine whose spiniUe reverses veiy rapidly. Among the important features of this particular die holder are the following: The backward movement of the .sliding die holding head a, which, as usual, occurs in running off the die or tap from the work, is never opposed by the guide fingers b b' , should they strike against the ends of driving pins c c' , as the guide fingers being pivoted at d d' swing out in this event. This prevents stripping of the thread. The spiral springs e e' serve to return and retain the guide fingers in their nonnal parallel position which is recjuired when the die or tap is cutting a thread. The edges of the guide fingers which come in sliding contact with the driving pins as sho\NTi are beveled to an angle of lo degrees with the line of travel of the die head. This angle obviously results in a freer forward movement to the die head than when there is a parallel sliding action, and also insures the lead of the thread conforming very closely to that of the die or tap. The angle could be carried to such a spiral as to tend to push the sUding head foi-ward immediately the die has caught. The l')-degrce slope, however, has proved very satisfactory. At / is shown a spring cushioning plunger which prevents undue shock when catching the first thread on the w'ork, and is especially efficient when cutting threads finer than 32 per inch. ADJUSTMENT FOR LENGTH OF THREAD Positive and uniform length of the thread being cut is insured by adjusting the .self-locking stop screw g. This stop screw determines the amount of travel which the die head a may have without rotating with the work. For instance, should it be desired to cut a ij-inch length of threatl, it is only necessary to adjust the nut forward until the amount of lap which the driving pins c c' have on guide fingers b b' is equal to I inch, as indicated at /(. After the die head has traveled forward enough to free the driving pins, no further thread cutting occurs, as the die head, then being free, revolves with the work. Wiien the spindle and work are reversed the die head usually reverses also until tlie lip on the groove in the die head at i comes in contact with the spring-actuated pawl /. Tliis. of course. l)revents further reverse rotation of the (.lie head, and as the work con- tinues to rotate the die is unscrewed. In case the die head due to its inertia does not reverse with the work 208 SCRE^\ MACHINE I'APS AND DIES ADJUSTMENT FOli LENGTH OF THRJCAI) 209 (as docs happen occasionally), and should the driving pins and fingers in this event he in direct line, there is no danger of strip|)ing the threads, for the guide fingers as before nientioneil will under tliese conditi(jns be causctl to swing outward during the backward movement of the head by the driving pins. A light si)iral spring A* serves, when the die is not cutting threads, to hold the die head back in the body with cushioning plunger against the stop screw. ;ind in use has the advantage of jireventing the marling of the first few threads on the work when backing off the die providing after the thicad has been cut, and previous to reveistil of the work, the turret, together with the holder, be pulled backward a distance ecjual to a couple of threads. This causes the spring to be in tension, and. after the spindle has ijeen reversed and the die unscrewed fiom the end of the woik, the spring brings the tlie head and die clear of the end of the piece that has been threaded. On account of the fact that absolute alinement of turret and spindle is not always retained and as dies spring in hardening, a slight floating action i)etween the sliding die head and body is allowed. Referring to the detail of the head, it will be seen that the shank is U.43o inch diameter while the hole in the botly is 0.437o inch. In some cases where old machines are used, considerably more than this freedom may ])e advisal)le; too much freedom, however, is bad, for then trouble mav result in starting on the die. CHAPTER XXV Forming Tools and Methods of Making Them Quite a variety of types of cutting tools and holders have been devel- oped for cross forming work on the automatic screw machine. For l^rass work flat-formed blades such as shown in Fig. 228 or solid forged tools as in Fig. 229 are found very satisfactory, owing to its being possible to obtain with these perfect side and peripheral clearances. Where frequent sharpening of the tool is required and where the form produced must be kept uniform, these tools are not always satis- factory, and a tool whose cutting edge can be sharpened without any alteration to its contour is generally preferred. Fig. 230 illustrates what is usually known as a circular forming tool. The grinding is done on face a h c d, the form as indicated extending entirely around the per- iphery. Fig. 231 illustrates another type of forming tool which admits of the cutting edge being re-ground without alteration of its contour. This is known by various names, a very common one being " dovetail forming tool " from the fact of its generally having a dovetail to fit into its holder. To prevent any confusion this tool will be referred to as a dovetail forming tool hereafter in this chapter. These tools are generally held and fed in such a manner that the cutting edge is on a radial line with the work being formed. In some special cases, however, it is fovmd more satisfactory for the tool to travel tangentially to the work instead of radially. COMPARISON OF TYPES There are various things to be taken into consideration when deter- mining whether to use a circular or a dovetail forming tool, and the fol- lowing points may be of assistance when making the decision: 1. The peripheral clearance angle being constant in both circular and dovetail tools, as shown by Fig. 232, it is clear that in the dovetail type there is more metal directly under the cutting edge than in the cir- cular tools to conduct away the heat which is produced while forming. 2. The difficulty and cost of producing an accurate and smooth form leave much in favor of the circular forming tool. 3. The type of tool post required for a circular forming tool oftentimes interferes with turret tools simultaneously operating on work with the cross-slide tools. The dovetail type of tool permits of the use of holders which do not thus interfere. 210 COMPARISON OF TYPES 211 212 FORMING TOOLS AND METHODS OF MAKING THEM 4. The increasing peripheral clearance of a circular forming tool per- mits a lesser angle to be utilized at the point of cutting than with the dove- tail type, and this lesser angle has a tendency to prevent chattering on account of the support afforded. With the dovetail type, stoning the clearance face is sometimes resorted to, which in effect gives a lesser angle at the cutting point, as indicated in Fig. 233 at B. A similar result with the circular tool without stoning the clearance edge is obtained by properly determining the relation of the center of the cutter to the center of the work as shown at B' , Fig. 234. Raising or lowering the cutting edge of the tool changes the clearance angle and incidentally changes the form produced. Consequently the clearance angles and the relation of the center of the cutter holding bolt to the work center are points wdrich it is necessary to consider carefully. DIAMETERS AND CLEARANCES With a given material the larger the diameter of the work the greater the angle of clearance required. Clearance angles are seldom less than 7 degrees and seldom over 12 degrees except on work out of the ordinary run. Tho diameter of circular forming tools is an important point to con- sidero A small diameter has a more pronounced change of clearance angle than a large diameter. In fact, when of an exceedingly large diam- eter the circular tool approaches in cutting action the dovetail type of tool. On the Pratt & Whitney automatic screw machines the standard outer diameters of circular forming cutters are as follows: No. machine. If -inch 0. D. cutter. No. 1 machine, 2-inch O. D. cutter. No. 2 machine, 2|-inch 0. D. cutter. No. 3 machine, 3-inch O. D. cutter. In order to obtain suitable peripheral clearance the practice is to locate the center of the cutter above the center of the work as at C, Fig. 235; the tool holder being bored out above the center as indicated and the forming tool milled out below center a corresponding amount so that its flat cutting surface is level with the center of the work. A very satis- factory amount to locate the circular tools above center and cut their working edges below for the machines just referred to is as follows: For No. machine, | inch; No. 1, t\ inch; No. 2, x\ inch; No. 3, fV inch. GETTING THE TOOL DIAMETERS AT DIFFERENT POINTS In order to produce a circular or a»dovetail type of tool so that the contour of its cutting edge is such as to produce correct work, the amount a circular tool is off center as C in Fig. 235 and the clearance angle of a TOOL -MAKING METHODS L'l:; dovetail tool as at I), Fig. 2'.V1, must be known. In connection with the circular type of tool the diagrams Figs. 'I'M), 2o7, 2."js and 'l'6\i will be NO.O AUTOM.VTIC FORMING TOOLS I?/'oUTSIDF, DIA. CUTTING EDCE^"bELOW CENTER. AMOUNT TO ADD TO APPARENT DIAMETER OF CUTTER, EACH GKADCAT10N=jOOOl(Tu^)liJCn. s ^ e; n <« t 1 -1 -J «9 r- 00 e> sJ^^Si I^Si?!^ M^S3S5 E.VCII (;ltAI>rATInient for (luickly ascertaining the diameters of the various sections of the tool. The method of using these diagrams is given in Fig. 2:i7. Where different diameters than tiio.^e given in the diagrams are used, or when the amount the cutter center is set off from the work center varies from the diagrams, the folhjwing formula may be used in connec- tion with Figs. 240 and 241: i -= g -^ if ■¥ a? - {:2a\^y^ - c). To compute the measurement T on dovetail tools, Figs. 240 and 242, the formula would be: T = a (cosine .4) Ten degrees is a veiy common clearance for dovetail tools; cosine 10° = 0.9X481. TOOL-MAKING METHODS There are various methods employed by the toolmaker in accurately making circular and dovetail forming tools. The form of tool has con- siderable to do with the scheme selected. For instance, if the work is entirely without curved or irregular outline the tool, if circular, would be simply turned up in an engine lathe to the correct dimensions, some- times making allowance for grinding, and then milling out a section for the cutting edge. In ca.se the cutter in question is of the dovetail form and has been correctly dimensioned, no difficulty will be experienced in accurately planing to dimensions if the toolmaker has proper dimensioned size blocks. The depth micrometer also is of value in this work. Some- times fly cutters are also u.sed for making these dovetail tools. 214 FORMING TOOLS AND METHODS OF MAKING THEM pj w H ^ [x] O ^ o _] « W w o Q H W ta n o y. F4 O ^ « O H hJ fi o Q H 'I O O H 5 ^ 'A oeoo- -05* -ef* -w -9S- -is- eg* -0£- S -eg* -og" -ir -or — < -er -sr -tr -GO" -80" -iO* -00* — J -w -80* -SO" -TO" -ef -OT* -eo* I?; to i w 2 fi M I?; O W ^-^ — I ® •-1 < % -3 P O 4J bo h .3 S CO "i a> m w a) a P< o O i 2 t Q ^ .»'A o ® o'S oj a o ^ O o tS H ,tn o o ,, , ■i; o o 3 «^ Q Hl-^ gi^ Is 1 QQ <1; -^ II S8 S N '^ '^ b/D t^ o 2 :?; 3 u a H " t<4 Z^ b .W n <-^ a 2 t; 00 w CI -OS* 216 FORMING TOOLS AND METDODS OF MAKING THEM fa ^ O _^ I -ii Is OS- er — sr -«• ff ir I — Of -GS* -is* 98* -eg- »8- — 88" — SS" IS- o H °. ^ II n - o O -LV -or -eg* ceoo* 6 __| — 02* -IT H ^^ !z; CO IS *=" 2 p O W — Og- c I STOO* — Gf ~ — sr " — IV -Of — ei' -n* -sr I — zv -TT -I OT' -co- -90- —SO* -w —80- -zo* J — TO- o a 'i fa H fa Tin: tuansii:r scheme 217 THK THANSI'KU S( IIK.MK It sometimes liappcns that ciicular cutters arc to bo made wliich arc vcrj' difficult to caliper; it is then (piitc frcviucnth" a(lvisal)le to turn a tool- sotting }iap;o of the correct (litimotor and copper plate the gajie (usinj; blue vitriol), and tiien to size the cutter correctly by first brinpnij; a master tool into contact with the gage, noting the grailuation on the micrometer collar on the feed screw of the lathe, then moving the carriage longitu- tlinally and bringing the master tool down upon the cutter to the same position. This scheme admits of several master tools being used, and in connection with microm(>ter stops or suitable size blocks for the longi- tudinal movement of the carriage accurate circular tools can be cconom- icaih" made. Fot Dovvtail Tools Ealar^tl HtictlOQ FIG. 242 ( ' FIG. :!4o FIG. 241 Finding Cuttiiifi Depths of Forming Tools Fig. 243 illustrates this transfer scheme, corresponding numbers indicating corresponding diameters of model and cutter. By simidtane- ovisly using a fixed dead tool arranged as a stop on center against the gage before referred to ami a master tool off center the amount the circular cutter is off from the work-center, the gage may be made of such diam- eters as would be cori'ect willi the cutting edges of tiie circular cutter on the radial line instead of being off center. Another modification of the scheme is to dispense witii the dead tool or stoj) n^ferred to and use a rigid master-tool-iiolding block capable of rapiil vertical adjustment which will jM'rmit of setting the master tools to the gage while on center and then allow them to l)e dropjXMl ])elow center an amount etimes W fouml of advantage to plane the face of the cutting edge of the blank to the 220 FORMING TOOLS AND METHODS OF MAKING THEM TOOL POSTS 221 corrof't anjiulrtr relation to the clcaranco face as at .1, Fi<;. 21S^ and tlieii scrilx' the eoiitour desired on this cuttinji face from a templet. if the teniplft is fastened to a l)l()ck as sliown, the siuipe of the finished soft cutter may also l)e nicely tested as in Fiji. 21!). As fre(|uent hardeninji; and annealinf; of tool steel is liable to affect its (luality. vaiious expedients are resorted to ni order to test the cor- rectne.ss of tools without undue waste. TE.STING OUTLINE OF FOHMIXC; TOOLS A common scheme is to mill the circular tool as in Fied with nuigazines for cast-iron sewing-machine hand wheels and similar work where considerable vaiiation in diameteis would recpure a very large 222 FORMING TOOLS AND METHODS OF MAKING THEM Fig. 254. — Adjustable Tool Post for Circular Forming Tools Fig. 255. — Adjustable Tool Posts for Circular Forming Tools TOOL POSTS 223 circular tool of the ordinary ty))c\ wiiich would bo unsatisfactory as rcfiards jx-riphcral clearances. Fig. 2.37 is a coniin(»ii d<)\ctail tool lujlder ami post. Fig. 258 repre- I'lu. 2.30. — Tool Posts tor T\V(j ('ireular Tools sonts another style of tool post for holding the dovetail type of tool. Fig. 2.)9 shows a tool post for holding flat tools. The tool is damped by screws a in swinging bloc-k b which is adjusted by screws c and damped N For Biii.liiis! Screwi y l'i(i. _'.")7. — Post for Dcivctail Tool Holder fast with the tool post to the cross slide by nut d. An eccentric pin e, adjusts the tool to position vertically, and the .'^winiiinjj; block gives the re(juired adjustment for side clearance. Tiiere are numerous other types, where pi-ovision is made for adjust- 224 FORMING TOOLS AND METHODS OF MAKING THEM ing the tool vertically by wedges, swinging anvils, etc. Fig. 260 illus- trates one of these posts with swinging anvil. Fig. 258. — Dovetail Forming Tool Post APPLICATION OF TOOLS TO WORK Generally, circular dovetail-forming tools do not have perfect side clearance. This feature is discussed in Chapter XXVII on "Why Chips Cling to Screw Machine Tools." Fig. 2.59. — Post for Straight Cut-off and Forming Tools One point that should be carefully considered in the use of cross-form- ing tools is whether it is most desirable to use a tool with the forward or reverse movement of the spindle. This is of particular importance when the forward and reverse speeds are greatly at variance, which is generally the case, as the production per hour may be greatly increased or decreased according to these conditions. The question as to whether a cross-feed- ing tool is to be in cutting action simultaneously with an opposite cross- feeding tool, or with a tool in the turret, is also to be considered in their connection. r<)RMi.\(; AM) rri{M.\fj 225 Fig. 201 illustrates a viuii'ty of work wliicli is common to the auto- matic screw maciiinc and shows various arrangements of f(jiining tools, seveial of which are adapted for simultaneous operations of front and rear tools which many times is conducive to a high rate of production as the cuts taken with each tool may bo greater than if either were operat- ing alone as the side pressure on the work is iKilanced. When the c(m- struction of the nuichine tloes not permit of the simultaneous cutting action, a similar arrangement of tools is satisfactory; only the time and sequence of their operations must he taken into consideration. Fiu. JOU. — Tool Post with Adjustable Shoe FORMING AND TURNING There arc a number of important iletails regarding the shape and method of using forming tools some of which will now i)e touched upon: Sketches A, A^, A-, Fig. 261, indicate a method of forming and cutting off a piece with two tools, one of which is, of coui.se, fed into the work before the other. The burs indicated by arrow points at .1- are due to the rubbing of tiie forming tools on the side cuts, and unless there Is perfect side clearance to the forming tool, the bur will be increased. By adding a bevel edge to the tool, as shown l)y ,1, the bur produced is re- removed. ,1* is a refinement over .1. M B is illustrated a common method of sinudtaneously cutting off and forming shoidder screws, the tw(j tools finishing their cuts at the same tim(\ Where a machine with single cross slide is used for producing work in this fashion, the cutting- off tool should precede the forming tool as the l)ar then has its full diam 226 FORMING TOOLS AND METHODS OF MAKING THEM :xfinement not always reciuiretl, but it is desiral)le when the l)ui' wiiich would l)e produced by the front tool is objectionable. M.\KIN(; SHORT S(1{KWS AM) OTHEIt P.VHTS At F, F\ F- antl F^ are shown several methods of forming and cutting off short screws. The method at F is a rapid one and is particularly reconnnended for machines with one cross slide, the cutting olT of the finished screw being accomplishe(l at the same time the forming of a ni'w blank is being done and re(iuiring a traverse movement of only about one-half the radius of the work. /•'' and F'- are applicable only to a machine with double cross slides in case sinudtaneous cutting action is (lesir(>d. These two methods are rajiid. both tools finishing their cuts at the same time. /•"- recpiii'es a more costly tool outfit, but on accovmt of balancing the cut is preferrecl wheic coarse feeds are taken or long work is to be formed. The method of i)roducing short screws indicated in h^ makes u.se of a rear cutting-olf tool after tlie forming tool has completed its work. 228 FORMING TOOLS AND METHODS OF MAKING THEM G illustrates a scheme which is of value where roughing antl finishing cuts are required on exceedingly accurate work. The roughing tool cuts off the piece previously formed and leaves a light cut for the finishing tool to take on the work outlined. H is self-explanatory, indicating the value of the turret support for the work. A PAIR OF DOVETAIL TOOLS A method is shown in Fig. 262 for getting perfect side clearance in dovetail-forming tools. The front tool is used for finishing the left-hand Fig. 262. — Forming with a Pair of Dovetail Tools sides of the work flanges and the rear tool for finishing the right-hand sides and the end, the tools being inclined in opposite direction so as to obtain clearance for these cuts. The tools are cut out as indicated by the arrows, at diagonally opposite points so that each cutter will clear the surfaces finished l^y the cutter opposite. Similarly, side clearance to circular tools is possible by inclining their axes. ARRANGEMENT OF CIRCULAR TOOLS In Fig. 2(33, sketches /, K, L, M show various ways of arianging forming tools with reference to the direction of rotation of the spindle. These are to be considered as being viewed from the turret, looking toward the head spindle. The arrangement at / is a most common one when a ARRANGEMENT OF ClRdLAR TOOLS 229 spring .screw div or a tap is to he used. The low-speed forward drive of the spintUe i.s used for the cro.ss forniinji; of the work (a.s at C'-C, F-F^, Fig. 201), while the high icver.se speed is utilized for removing the die or tap and for light cut ting-off cuts like that at F'. At A' is a .similar arrangement to J , and in some ca.ses this is substituted for the former, particularly wheie llic die or tap has a left-hand thread; the cutting-off tool is used at the front and the heavier forming cuts taken from the rear in this event. Fig. 26o. — Foriiiiii": Tool Positions /. and .1/ show ai'rangement of tools where they operate siniultanecnisly or wliere there is no necessity for reversing the direction of rotation of the heatl .spindle. In this latter case the spindle .speeds generally differ, and by carefully selecting tlie i)roper speeds a high rate of production will be possible. In all cros.><-forming work it is essential that the spindle fit snugly in its front l)earing and that the collet or chuck has a good parallel contact witli the bar which is being foi-med. A bell-mouthed collet is most fre([uently the cause of chatteiing, altliough excessive clearance may also j)romote chattering. The tool holder shoukl l)e of such design as to hold the tool fiinil}' and the cro.ss slide of such dimensions and so gibbed as to permit of no spring or shake. With careful attention to the.se details and providing the cuts are supported from the turret when they are wide, and also ]3ro- viding the design of the tool and the question of clearances are carefully considered, excellent results should be obtained. The rates of feed and the subject of lubricants are discus.-url Stud a FIG. 268 CD CD iiliia^SSl/ y fEsfH-^ 1 \ Xurl Studs /^Held Here f,^.f 1 yJ Surl Stud Holder. r^^l— ' A FIG. 267 Nurling Tools FIG. 269 232 NURLING TOOLS AND THEIR APPLICATIONS APPLICATIONS OF DIFFERENT METHODS Method A, owing to the absence of any side pressure, is recommended for all cylindrical nurling' operations when the length of the desired im- pression is greater than its diameter. In fact many operators use this method for all straight work. On complicated work where all the turret holes are required for the various cutting tools, it sometimes becomes necessary to use holders, which, in addition to holding the nurling tools, are so arranged as to hold an internal cutting tool such as a drill or coun- terbore. The holder must be stiff so as to hold the nurls to the work firmly without spring. Method B is only recommended for narrow nurling on soft metals close to the end of the head spindle. On hard materials or on wide work, the excessive pressure required to force the nurl into the work is apt to crowd the work away and produce poor results. Method C is a satisfactory means of nurling work up to a length equal to its diameter, providing the nurling is close to the end of the head spindle. The pressure required to force the nurl into the work is much less than by method B. These last two methods permit of all the turret holes being utilized for other operations, and as shown by Fig. 267, method C permits of the combining of the nurling and cutting-off operations in one holder. Method C may be satisfactorily used for nurling work as in Fig. 268, having several narrow steps, by arranging the holders to carry three nurl studs as indicated by Fig. 269. The nurls cut one after the other, and thus prevent undue pressure due to simultaneous action upon the work. END NURLING AND BURNISHING In addition to nurling upon the periphery of work, quite frequently end nurling as in Fig. 270 is required. This is satisfactorily accomplished by means of a turret nurl holder carrying a bevel nurl at a suitable angu- lar relation to the work as shown in Fig. 271. The method of applying burnishing rolls to short studs, scre-^s, etc., as referred to in connection with the manufacture of typewriter parts, is illustrated in Fig. 272. In this chapter the aim has been simply to outline the various methods and to point out where they might be successfully used, therefore no de- detailed description of the various types of holders or of methods of making nurls is given. RESULTS OBTAINED All of the methods described when used on work for which the}^ are recommended should give excellent results, providing the nurling of too heavy impressions for the character of the material is not attempted, and also providing the work is turned to proper circumferential tlimen- RESULTS OBTAINED 233 sions so as to mesh well with the pitch of the nuiliii Pratt it Whitney, e Box Tool Cutters) forming (see Forming Tools, also Circular and Dovetail Tools) Cylinder revolving and locking mechanism, Acme 100, 101 Gridley 124 D Deflector, Brown it Sharpe 46 Die and tap holders, Acme . 106. lOS Brown it Sluupi' 47. 49 Cleveland 75. 76 Prentice 150 Die and tap revolving attachment, Brown it Sharpe 49 head, Alfre.l Herbert 90 hohler, Cridley 85, 86 Pratt it Whitney 208 liolders 207 Dies and taps, sizing 206 testing threading action '-06 246 INDEX PAGES Dies and taps, types of 195 beveling work before running on 202 Dies, button 196 adjustment of 201 cutting action 201 cutting edge location 202 bobbing out 200 inserted chaser, Pratt & Whitney 196 inserted chasers for 200 speeds for 169 Dies, spring 196, 197 cause of chattering 199 clamp collars for 196 cutting edges 199 hardening 198 hob taps for 198 internal form 197 number of prongs 197 table of dimensions 206 tapping out 198 Double-spindle plain automatic machine, Cleveland 93, 94 work done on 94 Double-turret screw machine, Spencer 91, 92 work done on 92 Dovetail forming tools, clearance angle 213 clearance of 210-212 finding true cutting depth 213, 217 finishing with master tool 219, 220 methods of making 213-221 pair with proper clearance 228 planing 213 posts for 223-225 setting planing tool with micrometer and size blocks .... 219 templet for 219, 220 Drill and guide, Gridley 83 holders. Acme 106, 108 Alfred Herbert 90 relief 237 Drills and counterbores, flat 190 form of flute 237, 238 clearance of 189 counterbores and other internal cutting tools 187-194 serrated, stepped, and fluted lips 188, 189 single-lip 188, 189 starting 187, 188 twist and straight flute 188 Drilling and chamfering tool, combination, Cleveland 75 attachment, cross. Acme Ill speeds and feeds for 168 Drive for cam shaft (see Cam Shaft Drive) for spindle (see Spindle Drive) INDEX 247 E PAGES Eccoiitrio turiiiiif; mechanism, CJridloy semi-automatic piston ring machine 14.5 End-inilliiif; attachment, Acme 112 nuHinfj 2'.^ Kaciiifr liar, hack, Potter ^- .Johnston . . 1.37 tools 187, 188 P'eed and speed reguhition, Cleveland 7.3 cams for main tool slide, Acme 102, 10.3 for stock, Acme 100 Brown cV: Sharpe 42 ("levehmd 71 Pratt iV: Whitney, angles of . . 12 for turret, Pratt it Wliitney, finding angles of 17-20 change mechanism, Gridley multiple-spindle 122, 123 chucks, hardening 174 driving mechanism, Acme 97, 98 Brown «t Sharpe 39, 42 Cleveland 71 (iridley multiple-spindle 122, 123 Cridley single-spindle 80, 81 Potter A: Johnston . . 136 Pratt & Whitney s, 9, 10, 21 Universal . 1 16, 117 Prentice 148 magazine. Cleveland 126, 127 regulating cams, Cleveland . 70 shaft, tripping levers, etc.. Brown & Sharpe . 4.3 variation. Potter it Johnston 136 Feetis for screw madiine tools (see .Speeds and Feeds) with (litTerent cam angles, Pratt it Whitney, tables of 29-36 Finishing box tool, adjustable 17ti, 177 Fixture for grinding spring collets 173. 174 Flat drills and counterbores 190 reamers 192 Forming cams (see Cams, Cross Slide) long work, method of supjwrting 227 short screw ami other work 227 speeds and feeds for 167 Forming tool positions 226, 229 posts, adjustable 225 posts for straight tools 224 for two circular tools 223 Pratt & Whitney 221-225 Forming tools and methods of making them 210-229 and their clearances 21 1-213 applications to work 225-228 circular, diagrams for finding diameters 213-216 diameters 212 248 INDEX PAGES Forming tools, circular, finding diameters at different points 212-217 finding true cutting depth 213, 217 finishing in lathe 213 finishing with master tools 217, 219 finishing with transfer method 217, 218 location off-center 211-213 master tool fixture 218 master tool templet 218-220 testing 221 clearances of 210-212, 234, 235 dovetail, finishing with master tool 219, 220 pair with proper clearance 228 planing 213 setting planer tool with micrometer and size blocks 219 finding true cutting depth 213, 217 methods of making 213-221 types of , 210 G Gears, change (see Change Gear System) planetary for Pratt & Whitney feed-drive mechanism 8, 9 Gridley midtiple-spindle automatic turret lathe 119-125 capacity 125 indexing mechanism 124 feed-change mechanism 123 feed-driving mechanism 122, 123 spindle drive 121, 122 threading mechanism 123 tool slide 120-123 tool-slide cams 122, 123 Gridley semi-automatic piston ring machine 144-146 boring, turning and cutting-off tools 145 eccentric turning mechanism 145 piston ring casting 145 Gridley single-spindle automatic turret lathe 78-88 cam-shaft drive 80 capacity 78 countershaft arrangement 87 cro.ss-slide mechanism 82 die holder 85, 86 finishing slide, 12-inch 84 spindle and chucking mechanism 78, 79 spring collet and feed chuck 78, 79 turret-indexing mechanism 80, 81 turret slide and turret 78-80 with motor-drive and control 86-88 Grinding fixture for spring collets 174 INDEX 249 H PAGES HandliriK material in screw machine department 160 Hardeninj; spriiifi collets and feed chucks 172, 174 sprinfi (lies 198 Holders, die (see Die Holders) drill and counterbore 191 reamer, floating 192 Hollow-mill damp collars 182 ilimensions 182 tooth position 183 Hollow mills, Brown & Sharpe 47 spcetls antl feeds for 162, 165 I Iiitlepeiident cut-ofT attachment, Cleveland 7'.i Index for lajnng out Brown & Sharpe cams 54 Indexing cams, Pratt & Whitney turret, anjiles of 15 mechanism (see Turret Revolving and Locking Mechanism) Inserted chaser die, Pratt it Whitney 196 chasers for dies 200 J Jaws, spring-chuck, methotls of hardening 172 slitting 172 relieving on hearing surface 174 L Laying out Brown it Sharpe cams 52-63 index for 54 tallies for 61-63 typical layout (insert ) 54 Laying out Pratt it \\'hitney cams 12-36 tables for 29-36 typical layouts (insert 18) 13, 27 Locking bolt mechanism (see Turret Revolving and Locking Mechanism) Lubrication of work and tools 236 M Machine reamers and holders 191, 192 Magazine attachment, Cleveland 126, 127 tools for finishing pistons 127 Magazine automatic, Alfreoii(linfj fowls 29-.'10 arraii'reiiient 4 I'.i ilruiiis and disks -J, 5, l.'l (Iruiiis, (levelo|)iiieiit of l.i-JO, 27 'ayoiit (insert, 18) i;i ]<), 27 roll sj)aces Ki, 17_20 shaft ami spindle drive iliagram 22 shaft drive 8 22 cainmiii()7 die with inserted chasers KHi feed calculations for 1.) drivinsi mechanism S. <), lo, jl j)ulley diameters . 21-24 tables for 29-36 formitifi cams 4, i;j, 40, 26, 27 tool posts 221 22o indexing: mechanism for turret 6 nijikinp: and attaching cams 26, 28 pulley sizes and speed and feeil tables 33-36 spindle and chucking mechanism 4, 5 turret-locking bolt 118 N'arial lie-feed mechanism, Clevehuid W \\'eldin<_' of cliips to tools 234 \Vh\- chips cling to screw machine tools 234-238 UNIVERSITY OF CALIFORNIA LIBRARY Los Angeles This book is DUE on the last date stamped below. 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