US1720784A

US1720784A - Bolt centering, facing, and pointing machine

Info

Publication number: US1720784A
Application number: US41948A
Authority: US
Inventors: Jr James A Eden
Original assignee: WALTER H FOSTER
Current assignee: WALTER H FOSTER
Priority date: 1925-07-07
Filing date: 1925-07-07
Publication date: 1929-07-16
Anticipated expiration: 1946-07-16

Description

July 1, 1929. J, A, EDE JR LYZKLWM 55m cmwsame, moms, mm POINTING MACHINE 1s Sheets-Sheet 1 Filed July 7. 1925 gvwemboz Q mi flulfly WM. J. A. EDEN, JR

BOLT GENTERING, FACING, AND POINTING MACHINE Filed July '7} 1925 15 Sheets-Sheet 2 1 F. mJ "J, a Z fi NW NP m W H {a a Jim E Nb. u \N Nmmw n a s v v w QM WNN & mm a E 1 m@ @m No W W fiw w My M, 1929. J. A. EDEN, JIR

Bour CENTERING, meme, AND POINTING momma Filed July I; 1925 13 Sheets-Sheet 4 & mm

y 1929 J. A. EDEN, JR EJ203784 BOLT CENTERING, FACING, AND POINTING MACHINE Filed July 7. 1925 13 Sheets-Sheet 5 wuwkoz my J. A. EDEN, JR I 110720.784

BOLT cmwmzme, FACING, AND POIN'IING MACHINE Filed July '7. 1925 13 Sheets-Sheet 6 avwewtoz R J N E D E A m BOLT CENTERING, FACING, AND POINTING MACHINE Filed July 7. 1925 lSSheets-Sheet J A a fiuly fifi, @929. D JR 11.72%.784

BOLT CENTERING, FACING, AND POINTING MACHINE Filed July 7. 1925 l5 Sheets-Sheet 8 umes A Ede/7, L r. $13 @lbtomw BOLT CENTERING, FACING, AND POINTING MACHINE Filed July 7. 1925 13 Shets-Sheet 9 miaww y 1929- J. A. EDEN. JR 1.720.784

BOLT CENTERING, FACING AND POINTINGu MACHINE Filed July '7. 1925 13 Sheets-Sheet 10 Inn MQMM A ir /Jung My 16 1929. J. A. EDEN, JR 1.720.784

BOLT CENTERING, FACING, AND POINTING MACHINE Filed July 7. 1925 13 Sheets-Sheet ll y 1929- J. A. EDEN, m 1.720.784

I BOLT CENTERING, FACING, AND POINTI NG MACHINE Filed July '7.' 1925 13 Sheets-Sheet 12 v fluoamtoz tfa mesA. Ede/7, J2 3%? (3117120444 H29. .1. A. EDEN. JR

BOLT CENTERING, FACING, AND POINTING MACHINE Filed July 7. 1925 15 Sheets-Sheet l3 Fatented daily l lFF.

JAE-FEE A. EDEN", 3R, SPRINGFIEIBI), MASSACHUSETTS, ASS IGNOB TO 1E.

FOSTER, OF NEW YORK, 1t. "Y.

'hlQLT- (ENTERING, FACING,

Application filed July -I,

This invention relates in general to machine tools and while not limited thereto is particularly directed to means for drilling centering holes in the ends of bolt blanks and for facing the underside of the head and pointing or machining the end of the work blank opj posite the head. I An embodiment of the invention is illustrated in the accompanying drawings in 1 which Fig. 1 is a front elevation of the machine; Fig. 2 is a top plan view thereof Fig. 3 is an end elevation of the machine as viewed from the right of Fig. 1;

Fig. 4 is an end elevation of the machine as viewed from the left oi. Fig. 1;

Fig. 5 is an enlarged plan of the part shown at the left in Fig. 1;

Fig. 6 is an enlarged plan of the part shown at the right of Fig. 1;

ter drilling mechanism shown in Fig. 1, an intermediate portion of the machine being broken away;

Fig. 8 is a detail in central longitudinal section of the center drilling mechanism shown at the left in Fig. 7

Fig. 9 is a transverse section on line 9-9 of Fig. 8; v v Fig. 10 is an enlarged vertical longitudinal section on line 10-10 of Fig. 2;

- Fig. 11 is a transverse vertical section on line 11- -11 of Figs. 2 and 10; Fig. 12 is a detail view ofparts lying to the rear of the plane section illustrated in Fig.

Fig. 18 is a sectional view illustrating in detail the partsshown in elevation immedi-- ately thereunder in Fig. 11";

Fig. 19 is a sectional view on line 19-1 9 of Fig. 18 p Fig; 29 isfi'plan view of the dead center shown at the right in Figs. 1 and 2;

Fig. 7' is an enlarged elevation of the cen- Ann romaine Manama.

1925. Serial 110.41348.

Fig. 21 is a longitudinal section on line 21-21 of Fig. 20;

Fig. 22 is a transverse section on line 22-22 of Fig. 20; p

Fig. 23 is a view of a rough drop forged to bolt blank;

Fig. 24 is aview of the same blank after it has been center drilled; I

Fig. 25 illustrates the blank alter the bolt head has been faced on the underside; the shank necked adjacent the head; and the end pointed.

Fig. 26 is a front view of an alternative form of chuck;

Fig. 27 is a section on line 27-.-2'l' of Fig. 26; N

Fig. 28 is a detail section. on line 28-28 of Fig. 26;

- Fig. 29 is a detail view of an attachment.

Referring in detail to the drawings, the machine includes a base pan 10 sup orted on suitable legs12 which are secured to one another bv longitudinally extending rods 14- which also form a support tor a motor 16 carrying a pulley 18 which is connected by means 1 of a belt 20 with a pulley 22 carried on one 30 end of a main drive shaft 24 which is journalled in suitable bearings 26 and 28 secured to the base pan 10.

The shaft 242 carries a sprocket 30 which is connected by a chain 32 with a sprocket 34 carried on a' shaft 36 which is adapted to rotate the centering drill- 38 shown at the left in Fig. 1. A similar centering drill d0 shown at the right in Fig. 1 is adapted to be driven by a shaft 42 which carries a sprocket 44 which is connected by means of a chain 46 with a sprocket 48 secured to a short shaft 50. Also carried on this shaft is agear 52- vvhich meshes with a gear 64 slidingly mounted on the main shaft 24 and adapted to be rotated thereby.

The center drill '40 and its operating mechanism is mounted on a tail-stock 56 which slides on suitable guides formed on the base of the machine. ranged to be adjusted longitudinally of the base by means of feed screws 58 and 60 which pass through suitable nuts carried in the tail-stock. These two'screws are arranged to be rotated .in unison by a suitable crank handle fidysprockets 66 and 67 and chain 68. The sprockets 44 and 48 and the gears 52' and .54 are located between bracket'members 70 and 7 2 carried by the tail-stock. Hence, when the latter is adjusted to accommodate dif- This tail-stock is arferent sizes of work the gear 54 will slide along on the shaft 24.

The drills 38 and 40 are mounted in similar holders one of which is illustrated in detail in Fig. 8.- As here shown, the drill is carried by a known form of drill chuck 74. This-is carried on the end of a shaft 36. The drillis fed forward by means of a holder 76 slidin ly mounted in a suitable bearing 78. Said older is provided on its underside with rack teeth 80 which mesh with a pinion 82 carried on a stub shaft 84. The holder 7 6 has secured thereto a collar 86 which is adapted to limit the longitudinal movement of the holder and, hence, the inward movement of the drill 38.

Means are provided for simultaneously causing both drills 38 and 40 to approach the opposite ends of the work. The mechanism is such that both drills can be actuated from a point in juxtaposition to either of the drills.

' As shown in Fig. 9 the stub shaft 84 which carries the pinion 82 has keyed thereto a sleeve 88 having a flange 89 to which is riveted a sprocket 90. Loosely mounted on the sleeve 88 is another-sprocket 92. 'A crank handle 94 is secured to the stub shaft 84.

- carries on its end a weight 100. The stub shaft 98 carries a sprocket 102 and a crank handle 104 similar to that provided on the stub shaft 84. A chain 106 is dead ended on the sprocket 102 and asses from the underside thereof around t e top of the sprocket 92 on the shaft 84 .and carries a weight 108 on its end. By the above described connections, it will be appreciated that byturning eitherof the crank handles 94 or 104, both of the drills will be caused to move either toward or from the Work indicated at W. When the tail-stock is adjusted for diiferent sizes of work, the chains can be lifted to initially position the ends of the drill. And the setting of the stop collar 86 will determine the depth to which the center drills penetrate the work.

The work to be center drilled is held by an improved holding means which engages the work blanks in such a way that the axes thereof are automatically aligned with the center drills. These work holders are arranged to be rapidly and accurately set and released.

The work holder comprises upper and

lower jaws

110 and 112 mounted on the fixed part of the machine and adapted to grip the work nearone end, and similar jaws 114 and 116 carried by the movable member or tailstock andadapted to grip the other end of the work. The construction of both work holders is practically the same and a description of one will suflice for both, it being remembered, however, that one holder travels with the tail-stock and is arranged to be operated in the same manner regardless of its position of adjustment. As shown in Figs. 11 and 13, the upper jaw 110 of the work holder is provided on its underside with teeth '111 adapted to secure a good grip on the work blank W. The lower jaw 112 is provided with similar teeth 113. The jaw 110 is provided at the rear with a downwardly extendin shank 118 which slides'in a groove 120 forme in the supporting bracket 122. Mounted in a suitable recess in the bracket is a spring 124 which bears on the underside of'a stud 126 secured to the back of the shank 118 and tending to normally lift the jaw 110 out of engagement with the work. The lower end of the shank 118 extends forwardly and terminates in an upward projection 128 which is located beneath the center of the jaw 112. Longitudinally aligned cam members 130 and 132 (Fig. 7 are jointed to one another by dowels 134. The cam member 130 is arranged to actuate the

jaws

110 and 112 and the similar elongated member 132 is adapted to actuate the jaws 114 and 116 carried by the tail-stock regardless of its position of adjustment. The"

respective cam members

130 and 132 are secured to cylindrical bearing members such as shown at 135, in Figs. 7 and 13. The members 135 are rotatable in bearings 136. The

cam members

130 and 132 are so arranged that a heavy weight tends to hold the jaws firmly gripped against the work. The weight 13.8 for effecting this gripping action as shown in Figs. 4 and 13'is carried by a chain 140 one end of which is dead ended on a sprocket 142 secured to a shaft 144 the outer end of which is journalled in a suitable bearing 146 and the inner end of which is secured to the cam memher 130. As thus arranged, it is clear that when the

cam members

130 and 132 are in the position illustrated in Figs. 11 and 13 the weight exerts a force tending to hold the

aws

110 and 112 at one end and 114 and 116 at the other end of the blank firmly in place. For releasing the grip on the jaws, the shaft 144 is provided with a hand lever 148 by which the

cam members

130 and 132 can be turned so as to permit the lower aw to drop and the upper jaw to be raised by the spring 124.

For holding the jaws in open position, I provide a spring pressed latch 150 shown in Fig. 11 which has a tooth 152 for engagement with a similar tooth 154 carried by the handle 148. When the handle is in the dotted position shown in Fig. 11, the latch is adapted to prevent the weight from turning the cam. A

ferent sizes of work the gear 54 will slide along on the shaft 24.

The drills 38 and 40 are mounted in similar holders one of which is illustrated in detail in Fig. 8. As here shown, the drill 82 carried on a stub shaft 84. The holder 76 has secured thereto a collar 86 which is adapted to limit the longitudinal movement of the holder and, hence, the inward movement of the drill 38.

As shown in Fig. 9 the stub shaft 84 which carries the pinion 82 has keyed thereto a sleeve 88 having a flange 89 to which is riveted a sprocket 90. Loosely mounted on the sleeve 88 is another sprocket 92. A crank handle 94 is secured to the stub shaft 84. Rotation of the crank will turn the shaft 84 and sprocket 90 and pinion 82. One end of a chain 96 engages-the underside of a sprocket 90-and its extremity is pinned or dead ended on the sprocket. The other end of this chain is wrapped over the to of a similar sprocket carried ona stub sha t 98 mounted in suitable bearin s in the tail-stock and provided with a suita 1e pinion (similar to that shown at 82 in Fig. 9) and arranged to feed the drill to and from the work. The chain 96 carries on its end a weight 100. The stub shaft 98 carries a sprocket 102 and a crank handle 104 similar to that provided on the stub shaft 84. A chain 106 is dead ended on the sprocket 102 and asses from the underside thereof around t e top of the sprocket 92 on the shaft 84 and carries a weight 108 on its end. By" the above described connections, it will be appreciated that by turning either-of the crank handles 94 or 104, both of the drills will be caused to-move either toward or from the work indicated at W. When the tail-stock is adjusted for different sizes of work, the chains can be lifted to initially position the ends of the drill. And the setting of the stop collar 86 will deter: mine the depth to which the center drills penetrate the work.

The work holder comprises upper and

lower jaws

110 and 112 mounted on the fixed vided on its underside with teeth '111 adapted to secure a good grip on the work blank W. The lower jaw 112 is provided with similar teeth 113. The jaw 110 is provided at the rear with a downwardly extendin shank 118 which slidesin a groove 120 forme in the supporting bracket 122. Mounted in a suitable recess in the bracket is a spring 124 which bears on the underside of'a stud 126 secured to the back of the shank 118 and tending to normally lift the jaw 110 out of engagement with the work. The lower end of the shank 118 extends forwardly and terminates in an upward projection 128 which is located beneath the center of the jaw 112. Longitudinally aligned cam members 130 and 132 (Fig. 7) are jointed to one another by dowels 134. The cam member 130 is arranged to actuate the

jaws

110 and 112 and the similar elongated member 132 is adapted to actuate the jaws 114 and 116 carried by the tail-stock regardless of its position of adjustment. The

respective cam members

cam members

130 and 132 are so arranged that a heavy weight tends to hold the jaws firmly gripped against the work. The. weight 138 for effecting this gripping action as shown in Figs. 4 and 13is carried by a chain 140 one end of which is dead ended on a sprocket 142 secured to a shaft 144 the outer end of which is journalled in a suitable bearing 146 and the inner end of which is secured to the cam memupper jaw to be raised by the spring 124.

ess of its position trip 156 is pivoted at 158 to the handle and is so arranged that when the operator grasps the handle at the end, he will release the latch thus permitting the weight to turn the cams and thereby grip the blank at both ends.

' After a work blank, such as a rough forged bolt shown in Fig. 23, has been operated upon by the center drills 38 and 40, it will be in condition for'further machine work which is preferably done while the work'is supported on centers. Therefore, I preferably remove the work from the grip of, the holding jaws and insert it between the live and dead cen-' ters 160 and 162. To facilitate the rapid insertion and removal of the bolt blanks from between the live and dead centers, I provide improved means for moving the dead center.

The dead center 162 is mounted in a longitudinally movable member 164 (Fig. 21) which is slidable in a bracket 166 secured to the tail-stock 56. The member 164 has a block or projection 168 secured thereto which is adapted to ride in a cam slot 170 formed in a transversely movable slide, 172 which is mounted in a suitable groove or recess formed in the upper surface of the bracket 166. A

plate 174 is secured to the bracket 166 by suitable screws 176. It will be appreciated that the transverse sliding movement of the grooved plate 172 will cause the dead center 162 to either move in or out according to the Y direction of movement of the plate. For operating the sliding plate, I'provide a bandle 178 the forward end 180 of which is reduced in diameter and passes through an opening in a plate 182 secured to the end of the cam plate 172. The end of the handle 178 carries a spring 184 one end of which bears on a collar held in place by a nut I1l86 e opposite end of this spring bears against the plate 182. In operating the handle 178 to Withdraw the center, the operator pushes on the handle and this act causes the shoulder 188 to push against the plate 182 and thus cause the cam to withdraw the member 164 and with it the dead center 162. When a new work piece is inserted the operator pulls thefhandle until the dead center 162 encounters the end of the work. He then pulls the handle a little farther to'exert a slight compression on the spring 184 and thenengages one of the perforations 188 formed-in the handle with a locking pin 190 secured to' theplate 174. It is thus seen that the dead center is yieldingly held in engagement with the. work W.

The live center 160 is seatedin the tapered socket 192formed in theend of the drive spindl'e 194 which is rotatably mounted in head stock-

bearings

196 and 198. At one extremity the spindle 194 is reduced in diameter and screw threaded as at 199 for engagement with a similarly threaded hub of a face plate 200 to the front face of which is screwed or otherwise secured a chuck ring 202 having hexagonal aperture 204 formed therein for engagement with the head H of the work piece W.

Loosel mounted on a reduced portion of the spin le 194 is a spur gear, 206 having a rearwardly extending hub 208. To the latter is secured a larger gear 210. The main shaft 24 has slidingly secured thereon

gears

212 and 214 which are arranged to be meshed respectively either with the

gear

206 or 210, the first pair being used to rotate the work at high speed and the latter pair being engaged when a slower rotation of the work is desired. The gear 206 is provided with a suitable recess to accommodate a spring pressed clutch dog 216 the end of which is adapted to enter a recess 218 formed in the clutch member 220 keyed to the spindle 194. A sliding block 222 seated in the recess 218 is arranged to prevent the entrance of the pin 216 into the recess 218 when held in the position illustrated in Fig. 10 by the end224 of a clutch trip lever 226 which is pivotally mounted at 228 to a fixed bracket 230 (Fig. 14). The block 222 is formed with a recess 232 the entrance portion of which is bevelled 01f at 234. The extremity of the trip lever 226 is similarly bevelled and is adapted to reset the block 222 after the clutch has been tripped. The width of the trip lever 226 is such that it fits freely within an annular groove 235 formed in the clutch member 220. As long as the end 224 of the lever 226 is depressed, it is clear that.

the block 222 will beheld in the position shown in Figs. 10 and 15 thus the gears 206 and 21.0 rotate idly on the spindle 194. When by a rock shaft 244 having an arm 246 thereon which is connected by a link 248 at 249 with one end of the above mentioned clutch trip beseen that when the operator depresses the treadle 236 the clutch dog 216 will be permitted to establish a driving connection between the main drive shaft 24 and the spindle 194. The duration of this driving connection is controlled by a timing disc 250 carried on a shaft 252 which is connected by a gearing (hereinafter referred to), to the spindle 194. The timing disc 250 is provided with a notch 254. The extremity of the clutch trip lever 226 is formed with a projection 227 which rides on the 'periphery of the disc 250 after the clutch has been manually tripped thus holdingthe free end 224 in such position that the clutch member 220 remains operatively connected with the gear 206. However, as soon as the notch 254 reaches the lever 226; Through these connections, it will position shown in Fig. 14, a spring 256 rocks the lever 226 so as to depress its trip end 224,

hence, as the clutch member 220 approaches the position shown in Fig. 15 the bevelled end thereof strikes the bevelled portion 234 of the block 222 and thus pushes the clutch dog 216 clear of the clutch member 220. v

The gearin connecting the spindle 194 with the shaft 252 previously referred to, in-

thereto a change gear 274 meshing with a change gear 276 carried on the end of the above mentioned shaft'252 which carries the timing disc. The clutch and gearing above described provides driving means whereby cutting tools to be presently described can be brought into play in a predetermined manner so as to machine or finish desired parts of the work. The machine illustrated is provided with tools for facing the underside of the bolt head and for pointing the end of the blank.. These tools are moved toward the work by cams carried on the shaft 252.

Through the above described gearing these cams make one complete cycle and come to rest at the end thereof. During this cycle, of course, the Work makes many revolutions;

When the work blank is inserted between the live and dead centers the underside of the head asindicated at w in Fig. 24 is a rough surface. The end of the blank as indicated at e is also uneven. The tools are provided for machining the underside of the head smooth as indicated at W in Fig. 25 and for necking the shank of the bolt adjacent the .head as indicatedat W Another tool is provided for pointing or facing the end to a smooth finish as indicated at e in Fig. 25.

For making the roughing out under the head of the bolt blank, I provide a roughing justably secured to the slide 282 by bolts 283 bears on a. late 302 secured to the rear of.

the slide.

tool 278 (Fig. 11) carried in a holder 280 secured to a tool slide 282 mounted on aguide 284 secured to the base of the machine. Ad-

is a bracket 286 carrying a roller 288 for coaction with a cam 290 secured to the shaft 252. The adjusting screw 292 engagesposts 294 and 296 carried respectively by theslide 282 and the bracket 286 so as to permit slight j adjustment to compensate for wear on the cutting tool or for setting the parts for opera- 7 tion on blanks of varying sizes. The underside of the slide 282 is recessed for the reception of a spring 298 one end of which bears on afixed stud 300 and the other end of which thus arran ed, it is'clear-that upon rotation of the sha 252 the earn 290:

'will advance the roughening tool 278 while After the roughing out has been made bythe tool 278 a finish ing tool- 304 comes into play and takes a very light cut on the underside of the bolt head and also necks or takes a light out to form the finished portion indicated at W in Fig. 25. If desired this neck, of course, can be formed initially by the roughing tool 278 and finally finished by the tool 304. The finishing tool is carried in a holder 306 which is adjustably secured to the free end 308 of a lever 310 pivoted on a stud 312 secured to a bearing 314. This lever carries at its outer end a cam roller 316 for coaction with a finishing cam 318 secured to the shaft 252. A spring 320 is anchored at one end to any fixed part of the machine and at the other end to a pin 322 secured to the underside of the lever 310. The relative positions-and'contours of the

cams

290 and 318 can be varied to suit requiremei-ls of the work as will be understood.

For pointing the blank, that is to say, facing the end as indicated ate in Fig. 2 1,1 provide a pointing tool 324 which is curved at 326 to the desired contour. This tool is mounted in a holder 328 which is securedto a slide 330 movable on a suitable guide 332 formed on the movable tailstock 56; The

slide 330 carries a bracket 334 which is ad-.

screw 337. At its end the bracket 334 carries a roller 336 for coaction with a cam 338 on the shaft 252. The slide 330 is adapted to be advanced toward the work by the cam 338 and a spring 340 is provided for returning vthe slide under control of the cam.

The advantages of the machine constructed as above described will be readily apparent to those skilled in the art. It will be seen at once that by mounting one of the centering drills and one of the work holding clamps on the movable slide or tail-stock, that the machine can be readily set for work on blanks of different lengths. The flexiblejcrossed chains for transmitting movement from one centering drill spindle to the other is quickly and easily adjusted when the tail-stock is moved to operate on longer or "shorter blanks than those shown. I The automatic cam actuated cutting tools accomplish their work in re spouse. to afootactuation of the clutch treadle after whichlthego erator-is free to clamp anotherworkblank 1n place and center drill the 1 same while the previously centered blank is 'bein automatically 'pointed at the end and face under the'head.

Inoperation, assuming that the

clam ing jaws

110, 112, 114 and116 are open an the 'handle 148 is in the dotted position shown in Fig. 12, the operator inserts a rough forged of the work to a depth determined by the position of the stop 86. Either the

handle

92 or 104 is then operated to retract the center drills and the clamp control handle 148 is depressed to release the work from the holding jaws. The operator then inserts the head H' of the blank into the hexagonal aperture 204 of the chuck 202 and pulls the handle 178 so as to move the dead center 162 into engagement with the center hole previously formed in the end of the work. The handle 178 is pulled a sufiicient distance to put the spring 180 under slight compression and then the handle is depressed so as to engage one of the apertures 188 with the locking pin 190. During the insertion of the work, the spindle 194 is at rest- The operator now depresses the treadle 136. This establishes a driving connection between the main shaft 24 and the spindle and also sets in m tion the shaft 252 which carries-the cams for advancing the roughening, finishing and pointing tools. During one revolution of the shaft 252 each of the tools comes into play at a predetermined time in the cycle so as to face the underside of the bolt head, form a neck adjacent thereto and also to point the end of the blank. At the completion ofithis work, the tool carriages are returned and the end 227 of the clutch control lever enters the notch 254 in the timing disc thus breaking the driving connection to the cam shaft 252 and completing the cycle. The operator now lifts the handle 17 8 to disengage it from the locking pin 190 and by pushing the handle causes the cam .slot 1 co-operating with the projecting block 168, to withdraw the dead center 162 and thus permit the bolt blank to be removed.

In Figs. 26 to 28 inclusive, I have illustrated a form of chuck which may be used as an alternative for the one shown at 202 in Fig. 10. This alternative form of chuck ineludes a body 400 formed with suitable guide slots 402 in which are mounted jaws 404. There are preferably three of these jaws arranged 120 apart as shown in Fig. 26 for engagement with the flats of the hexagonal head of the bolt. The body of "the chuck is floatingly secured to the face plate 200 by means of-a plurality of shouldered studs 406 which pass through clearance holes 408 formed in the chue body. Said studs have threaded shanks 410 which are screwed into the face plate 200 and clampmg screws 412 serve] to lock the studs against accidental turning. The heads 4140f the studs are seated in suitable counterbores 416 as shown.

The jaws 400 are propelled toward and from the center of the chuck by means of adjusting screws 418 whose threads engage the threaded edges 420 of the jaws 404. These adjusting screws are provided with square holes 42 at their ends for coaction with a suitable rench. At their inner ends, the adjusting screws are notched as at 424 for cooperation with a spring pressed locking pin 426 best shown in Fig. 27. On the face of the chuck a number of index marks 428 are provided opposite the jaws to enable the operator to quickly set the latter for engagement with different sizes of bolt heads.

- Because the jaws do not tightly engage the flat portions of the bolt and in view of the clearance between the studs 406 and the holes 408, the chuck can partake of slight relative movement with respect to the face plate 200 to compensate or allow for inaccuracies in the shape of the bolt head. That is to say, if the flats or the apothem of the hexagon is not concentric with the axis of the bolt (which it will be remembered is held on centers) the chuck I part of the framework of the machine in juxtaposition to one of the gears such as at 276 and 268. The bracket 430 carries a boss 432 in which is journalled a stub shaft 434 having a pinion 436 on one end thereof which is adapted to mesh with one of the gears, for example either 27 6 or 268 according to the location at which the bracket is secured. The end of the shaft 434 opposite the gear 436 is squared off as shown at 438 for engagement with either a wrench or suitable handle by which the operator can rotate the shaft slow- 1y so as to turn over the machine for the purpose determining that the various holes ave been properly set. The provision of this hand turning attachment saves damaging the parts of the machine due to the operator carelessly securing the cutting tools in their holders in such manner that the cams throw them too great a distance.

The machine shown is well adapted for use in connection with vertical bolt turning and threading machines employin a traveling cutter-head covered by other den patents. When used in connection with such turning or threading machines, the output thereof is not held down by the time required for facing the undersides of the heads of blapks and pointing the ends thereof. The bolt'blanks are machined in batches with the machine herein described by unskilled operators and the threading and turning of the long shanks nected with one of said sprockets,

can be economically done in gang machines of the Eden type having vertically traveling cutter-heads.

Though I have described with great particularity the specific embodiment of the invention illustrated, it is not to be construed that I am limited thereto as various modifications may be made by'those skilled in the art without departing from the invention as defined in the appended claims' What I claim is I 1. In a machine of the class described means for holding the work, a pair of aligned center drills carried in holders having rackteeth, pinions engaging the latter, a sprocket for actuating each plnion, a chain engaging both sprockets and having a weight on'one end and the other end being secured to one of said sprockets and a manually operated crank con- 2. In .a machine of the, class described a separate work holder for holding each end of the work, each holder comprising coacting jaws a pair of aligne centering drills, means or simultaneously moving the latter toward the opposite ends ofthe work including a single manually operated crank, one of said drills and one of said work holders being mounted on a support which is movable to accommodate different lengths of work, an operating member common to both work holders and a weight tending to turn said operating member.

3. In a machine of the class described a blanks of diflerent lengths, centering drills,

work holder comprising a pair of coactin clamp jaws, an actuat'in cam common to bot jaws, aweight arrange to turnsaid cam and thus exert a grippingaction on the work and means for simultaneously drilling centering holes in the opposite ends of the work and a spring tending to release one of said jaws.

4Q In a machine of the class described means 1 for holding the work, centering drills, means for advancing said drills toward the ends of the work, means for rotating the work, a plu- *rality of cutting tools and cams forautomatia pair of.

and fixed supports.

cally moving the latter into engagement with the work and driving mechanism for said cams which is rendered non-operative after the work has been rotated a predetermined number of revolutions.

5. In a machine of, the class described means for holding the work, centering drills,means for advancing said drills toward the ends of the work, means for rotating the work, facing tools, a shaft carrying cams which advance the tools toward the work and means for automatically interrupting the rotation of said shaft upon the completion of a determined number of revolutions of the work.

6. In a machine of the class described a head stock including a live center and means 1 for rotatitng the work, a movable tail-stock carrying a dead center and means for drilling centerin holes in the work including a fixed work ho deradjacent the live center and a holder mounted on the tailstock adjacent the dead center and means for simultaneously actuating both holders.

7. A machine of the class described including a centering drill and a work holder mount ed on fixed supports, a similar drill and work holder mounted on a movable sup ort, and respective means for simultaneous y actuating both drills and both work holders regardposition of said movable less of the relative ,8. In a machine for centering and truing bolt blanks, a pair of work holding members one of which is movable to accommodate means for, moving the latter toward the ends of'the work, means for quickly releasing the holding members, means for rotating the work between centers, a tool for facing the underside of the bolt head, a tool for pointing the end of the blank and means for automatically moving said tools into andout of engagement with the work. In witness whereof,"I have hereunto signed my name.

- JAMES A. EDEN, JR.