US1239532A - Machine for calibrating and straightening gun-barrels. - Google Patents

Description

APPLICATION FILED NOV. 3. 1915.

Patented Sept. 11, 1917.

6 SHEETSS HEET I.

V azwwwgww C.-W. SPONSEL.

MACHINE FOR CALIBRATING AND STRAIGHTENING GUN BARRELS.

' APPLICATION FILED NOV. 3. 1915.

L%'9,532.- Patentedsept. 11,1917.

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C. W. SPONSEL. MACHINE FOR CALI BRATING AND smmmmwe sum mans. APPLICATION FILED NOYV. 3.1915, LQQfiSQV PatentedSept. 11, 1917.

6 SHEETS 4SHEET 3- W m I I ww EV c. w. SPONS EL'. MACHINE FOR CALIBRAT INGAND. STRAIGHTENING GUN BARRE'LS.

APPLlcAHoN FILED NOV. 3. 1915.

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IIMACHINI-Q FOR CAIJBRATING AND STRAIGHTE'NINB Gum BARRELS. AYAPPLICATIOII FILED NOV. 3. I915.

, 6 SHEETS-SHEET 5- I C. W. SPONSEL. v MACHINE FOR CALISBRATING AND STRAIGHTENING GUN BARRELS.

APPLICATION FILED NOV. 3. 1915. 1,39,532n PatentedSept. 11, 191?.

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. kmfk CHARLES w. sroivsnn, or HARTFORD; CONNECTICUT, ASSIGNOR 'ro THE SPONSEL COMPANY, or HARTFORD, oolvivno rrou'r, A. oonronnrroiuor CONNECTICUT.

",JMAGHINE non" cALI nArnve AND srnnrenrnivina eon-Bantams.

Specification of Letters Patent.

Patented S ept. ii,- rear Application filed November 3', 1915. Serial No. 59,361.

To all whom: may concern:

Be it known that LiGnAnnns SroNsEL, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, haveinvented a new and useful Improvement inMachines for Calibrating and Straightening Gun-Barrels, of which the following is a specification.

During the manufacture of barrels for rifles and machine guns, when the'forged or rolled billet is being drilled for the bore, it frequently happens that owing to a variation in the hardness of the metal, or from othercauses, the drill as it advances works off an elevation of the left hand end. Fig. 4: shows a vertical section taken on the dotted line H on Fig. 2, looking in the direction indicated bythe arrows. Fig. 5 shows a section of one of the insulated pulleys about which the charge wire carrying the contact thatis adapted to be fed through the barrel, is passed, this pulley being adjustable toward thefront and back toobtain parallelism of the contact wire and the barrel support. Fig. 6 shows on larger scale a plan of the two insulated pulleys about which the charged contact wire and the indicator wire pass, and the means by which more or less to one side, withthe resultthat the contact wire is held taut. Fig. 7 shows a the axis of the bore is not straight,'but is front view, with parts in section, of the plate somewhat curved between the endsof the to which the ends of the contact and indibarrel. This invention relates to a machine cator wires are attached. Fig. 8 shows an which is designedto detect and remedy any end view of the wire attaching plate and the such inaccuracy in the bore of a gun barrel. means for ,temporarily clamping it. Fig. The object of the invention is toconstruct 9 shows a plan of apart of the gun barrel a machine,into which gun barrels can be supporting carriage and the means for mov quickly placed, having means that will elecing and measuring the amount of movement trically indicate deflections of the bores and of the carriage toward the front and back. mechanically measure the amount of varia- F ig. 10 shows a front view of a part of the tion from true, and having meansby which carriage and the measuring gage. Fig. 11 the barrels can be bent andstraightened so shows asection on the plane indicated by as to overcome the inaccuracy indicated by the dottedline 11- 11- on Fig. 2.. Fig. 12 the electrical means and registeredby the is a diagrammatic illustration of the elecmechanical means. t-ric circuit by means oi? which discrepancies The machine illustrated as embodying this invention has a contact in an electrical circuitcontainmg lamps, wh1ch 1s adapted to be fed along the bore of a gun barrel, and

in the bore of a barrel may be visually indicated; Fig. 13 illustrates the arrangement of the mechanism when the bending mecha nisms are so located as to act upon the barrel means for moving the barrel sidewise with with a-deflection indicator passing through it. the electrical contactinsidd'and a gage for Themachine illustrated is mounted upon measurin the amount of such movement, alea'st iron base 1. As stated, for simplifythe electrical circuit being so arranged that ing the illustrationand description themawhen the contact touches any point along chine is shown with the bending mechanism the wall of the borethe circuit conditions which is provided for remedying the defects will be changed in such manner that the indicated by the calibrating means, arranged lamps will show the altered conditions and in t'rontoi. and below thecalibrating means. the gage will measure the amount of varia- In this type of machine there is a shelf 2 on tion from aceui'acy,there being associated the front of the base, and in the top of this with the indicating and measuring means, shelf and extendingFfrom end to end across mechanism for bendingthe barreland rectithe. .frontzis a 'T-shaped guideway At fying whatever error is shown. The bendeach'end of the guideway is a supporting ing means may be arranged to operateupon yoke 4 for retaining the end of a gun bar the barrel while in. testing position, but for rel. Movable along the guideway on the top the sake of clearness, in the accompanying of the shelf are two grooved barrel holding illustrations, that means is located below and in frontof the testing means.

Figure 1- of the accompanying drawings shows a-tront elevation of the machine. Fig; 2 shows a plan of the'machinefl Fig. 3 shows blocks '5. At approximately the middle of thevmaehine and projecting downwardly over the guidewayis a stud 6 mounted in thefront end of a lever 7. This studis screw threaded sothat it may be adjusted up link 10 that is hinged to the upper rear end of the arm 11 of the foot lever or treadle 12 which 'ispivoted to the frame and is normally lifted by the spring 13 (Figs. 1, 2 and Y After the amount of deflection of the bore of the barrel has been determined the barrel is laid on the blocks 5 which are moved toward or from each other so as to support the barrel in the necessary position, and then when the treadle is depressed by the application of the foot, the toggle links force down the stud which has been adj usted. to the necessary position and cause it. to bend the barrel between the blocks the re quired amountto straighten it and rectify the defect which has, been found. The calibrating mechanisms are arranged on a table 14 mounted on the top of the base. Movable along a way on the top of the table toward the front and rear is a carriage'lfi. Afine feed screw-16 having on its front end a hand wheel 17 is arranged to turn in the carriage and in a nut 18 held on the table for moving the carriage forward and back ward. A stop screw 19 turning througha plate 20 on theback of the carriage isarranged to engage a post 21 mounted on the table for determining the limit .offorward movement ,of the carriage. ,On the feed screw back of the handle is a graduated dialplate 22 designed to register with a .zero mark on the carriage'for showing the number of'turns of the screw and indicating the amount of movement of the carriage. This dial-plate is desirably held in place by a wedge pin 23 mountedradially in the screw spindle and adapted to be forced out against the inner wall of the hub of the dial-plate by a thumb screw 24 that turns into the end of the'feedscrew spindle from in front of the hand wheel. (Fig. 9). By means of this mechanism the dial-plate canbe adjusted and set to any desired position with relation to the zero mark. 611 top of the carriage at one end are two barrel supporting pillows 25 and 26. These are desirably fixed in position on the carriage. At the other end of the carriage are two barrel supporting pillows 27and 28. These are arranged so that th-ey may be adjusted along slots in the carriage, thereby enabling barrels of different lengths to be placed in and supported by the 'pillows.

On the top of the table near the right hand end of the machine is a. guideway 29 provided with the fixed rack 30, and movable along this guidewayis a slide 31. Mounted in this slide and engaging the rack is a gear wheel 32 on the end of a spindle 33; that-at the front of the machine has a hand wheel normal position the feeler rod will be approximately in line with the axis of the bore of a barrel that-is laid withits ends in the pillows 25 and 27, and the indicator rod will be parallel thereto at such a distance in front that it will extend along the outside of the barrel when the feeler .rod isin the interior. The indicator rod isthe same length as the feeler rod and is provided to show the location of the tip. of the feeler rod when it is in the interior ofa barrel. The clamped end of-the feeler rod is mounted in an insulating bushing so that the rod will .be electrically insulated from the other parts of the machine (Fig. 11). Then these rods 36 and 38 ar'enot being used. for determining variation in the bore. of a barrel the block which supports them is turned on its hinge toward the front of the machine.

. Hinged to the top of a post 41 that extends up from the slide lSeZtcommon style of dial-gage 42. A setscrew 4A is mounted on a portion. of the post that supports the dial-gage so that when the gage is turned down to the position in which it is used it will be exactly horizontai' and its contact stem 43 will point toward the axis of the bore of" the barrel (Fig. 11). r The ends of the. barrel are first turn-ed off so' the outer surfaces will be concentric with the bore, then plugs may be inserted a short distance into the bore and allowed) to pro ject some -'.distance beyond the ends. The barrel thus plugged is laid in the pillows 25 and 27 and rotated with, the dial-gage stem against the plugs. By this means the plane of any curve in the barrel may be roughly ascertained. .l/Vhen the dial-gage is not to be used it is t'urnedron its hinge over toward the back of the machine.

, Pulleys 45 and 46 are mounted on the top of the table near each end of the-machine. The pulley i5 turns on a stud 47, suitable anti-friction bearings 48Qbeing interposed, which projects upwardly .froma disk 49, that'has. an eccentric stem 50 rotarily supported by the table. Extending from one side of the disk 49 is an arm 51' that is held between screws 52 turning in a block 53 which is secured to the top ,of the table. By manipulating these screwsthe disk bearing the pulley arbor may be turned so that the pulley can be adjusted slightly toward the front or rear (Figs. 5 and 6). The other pulley 4:6 is mounted on an arbor which projects upwardlyv from a'slide 5% that is movable sidewise of the bed back head pulleys below the first wire, and one end 70 and forth on a way on the-top of the machinew At the outer end of this slide'is a wall 59, and loosely passing through perforations in this wall are bolts 57 that at their inner ends are secured to a cross head 58 and at their outer ends are secured to a cross head 61. Springs 56 are plaoedon the bolts 57 so as to thrust betweenthe cross 58 at the inner ends of the bolts and the wall 59 at the outer end of the slide. These parts arranged in this way form a yielding extension for the end of the slide. A cam 60 which is mounted on a fixed pivot 600 is adapted to engage across head 61 on the outer ends of the bolts, in such manner that, when its handle 62 is turned to one position, it draws the slide out with a stiff spring pressure, and when the handle is turned to the other position it relaxes the tension on the springs and permits the slide and pulley 46 to relax toward the pulley 45 (Figs. 1 and 6.) The two pulleys are desirably made of metal and they are mounted on suitable anti-friction bearings and provided'with handles 63 bywhich they may be rotated. Each of the pulleys has on its periphery a ring of electrical insulation 64.

Extending around the pulleys is a Wire or metal cable 65. This Wire in passing around the pulleys runs in a small groove in the insulating-ring, and one end is looped and hooked into one end of a plate 66,. while the other end is looped'and hooked into the other end of the same plate. The pulley 46 is drawn outby the springs as above described so as to hold this wire very taut. The front section of this wire is located so that .it will extend through the bore of the gun barrel that is placed in thepillow blocks 26 and 28. If the wire in front is not exactly parallel with the axis of the bore of a barrel that rests inthese blocks, the pulley 45 is by means of its eccentric support adjusted until the wire is parallel. In order to string the wire through the barrel the cam handle 62 is turned to the left so as to relax the tension of the springs against the slide. This .releases the slide and the pulley46 moves in and slackens the wire so that its end can be unhooked from the connecting plate. After thiswire has been threaded througha f gun barrel it is again carried around the pulley 46 andits end hooked onto the plate 66, and then the handle 62 is turned so that the cam will again put tension on thesprlngs and cause them to draw backthe pulley and take up all slack in the wire. On this: wire near one end is a small contact disk 68. i

A second wire 69is passed around the ishooked into the plate 66, while the other end 71 is connected with a plunger 72 that is held by a spring 73 so that this wire will alwaysbetauteven when the pulley 46 is ,wire (Fig. 7).

allowed to move in so as to slacken the other The lower Wire is passed over insulating pulleys 74 which hold it out in front of the upper wire. This wire is designed to extend on the outside of the barrel and it has a small indicator disk 7 5 which is exactly opposite to the contact disk 68 on the wire that passes through the barrel and is for the sole purpose of indicating the position of the contact when that contact is in the interior of a barrel (Fig. 6). on a shaft provided with a handle 7 7 is arranged to be turned down onto an insulating block 7 8 on the upper edge of the plate 66 to which the wires are attached, for the purpose of holding that plate from movement when the pulley 46 is released to slackcn the contact wire (Figs. 7 and 8). At each end of the travel of the wire attachment plate 66 is an insulating frame 79 which forms a guide and stop for the plate, and the plate travels in its movement from one to the other, on a stripof insulation 80 (Fig. 6). As a result of this construction the contact wire is electrically insulated from the rest of the machine, and when the handle of either of the pulleys is turned the wire runs around them and carries the contact 68 along the interior from one end to the other of a barrel placed in the pillows 26 and 28.

At the right hand end of the machine is a metal plate 81, preferably brass. This plate is fastened on to an insulating strip 82 so that it is electrically insulated from the rest of the machine. A spring contact finger 83 has one end connected to this plate, and has its other end bearing against the contact Wire 65 that is designed to be passed through theborc of the barrel. Ablock 84 fastened to the slide 31 that moves back and forth along the righthand end of the machine carries a spring plunger 85 that is thrust down into contact with the plate 81. This plunger is insulated from its support, and a wire 86 leads from it to the end ofthe feeler rod 36 (Fig. 11).

A pair of electric lamps 87 may be mounted on the table and connected in series with a current transformer 88, or other source of power. The contact plate 81 may be connected by side of the lamps. A. wire 90 leading from betweenthe lamps is grounded on themaohine (Figs. 2 and 12). lVith these connections,when the contact on the wire 65 that passes through the barrel is not grounded on themachine by touching the barrel, or the rod 36 is not grounded on the machine by touching the barrel, current will flow through both lamps and keep them lighted.

Whenever the live wire contact, or the end of the live feeler rod, is grounded on the machine, as forinstance, through contact with the inner wall of a gunbarrel, one of the lamps will be short circuited and all of the A cam 76 the plugs removed and current will flow through the other lamp, showing that either the contact on the wire or the tip of the feeler rod is touching the barrel. V

In using this machine a barrel plugged as described may be placed in the pillows 25 and 27, and the plane of any deflection oi the bore be roughly ascertained by the dialgage. While this is being done the. rods 36 and 38 are thrown over to the front. The dial-gage is then thrown over to the back, the rods are turned down to normal position. The slide is moved up gradually and the rod 36 passes into the bore of the barrel. At various times as this rod is being passed into the bore of the barrel the main carriage which supports the barrel is moved back untilthe tip of the rod 36 engages the inner wall of the barrel, under which condition, as de scribed, one of the lights will go out. From the gage on the carriage the amount of movement backward of the barrel is determined. Thus with this mechanism the distance that the barrel is moved back at the various points is measured and any curva-- tureinthe axis of the bore indicated. After this has been determined at one end of the barrel, the barrel may be turned around and by the same method the accuracy of the bore at the other end otthe barrel may be determined.

After the barrel has been gaged and bent by the mechanism described, to overcome any curvature in the bore, it may be placed in the pillows 2G and 28. which passes around the pulleys is then threaded through the bore, the pulley 46 having been loosened so, as to slacken the end of the wire and allowit to be readily: unhooked and after threading rehooked onto the connecting plate. Then the pulley 46 is drawn back by the cam lever and either pulley turned so that the charged contact wire will carry the contact through the bore of the gun. It the bore is true the contact will travel through it without making any change in the electrical circuits. ,However, if the contact touches the wall of the barrel, as stated, one of the lamps goes out and then the carriage supporting the barrel can be moved by turning the hand wheel until the contact is broken and the lamp again lights, the distance of which movement is measured by the carriage gage so as to show the amount of the defect. The barrel is marked on the outside opposite'the indicator, which 'is opposite the contact, so as to show on the outside where the contact engaged the wall of. the bore. When the irregularities have been determined the wire is unhooked and the barrel taken off and placed in the straightener for bending. After the barrel has been bent it can if desired be again tested. lVith this mechanism very slightv The wire 65,

As shown in Fig. 13 the barrel may be bent for straightening it while the charged indicator wire is passing through it. In this case the barrel is mounted on pillow blocks 91 thatare adjustable along away 92 on the top of the table, and thebending stud 93 mounted in the upper end of the lever 94 that is capable of being forced down by the treadle, asshown in Fig. 3, is arranged above the. barrel. The live wire 95 passing around the insulated pulleys 96 and 97 carries the contact 98 as previously described. The connections forelectrifying the wire and this contact may be as represented by the diagrammatic illustration in Fig. 12. If the contact in being carried through the barrel touches the wall of the boreat any place the circuit is grounded through the barrel and t-he'charge indicated by the lamps.- The barrels are then bent until this deflection is remedied. I The invention claimed is; 1. Aanachine for calibrating gunbarrels, having means for supporting barrel, a wire bearing a feel'er and adapted to be moved longitudinally back and forth in the bore of the barrel held by said supports, means for holding the wire taut, means for indicating the engagement of ,said feeler with the wall of the bore of the barrel, said means being controlled by such engagement, and meansfor showing on the exterior the point of contact of the feeler" with the wall of the bore, said means being connected to 2. A machine for calibrating gun barrels,

having means. for supporting a barrel, a wire,

bearing a feeler and adapted to bemoved longitudinally back and forthin the bore of.

the barrelheld by said support, means holdlng the w1re taut,-mechanism for imparting relatlve transverse movement between the barrel support and the feeler sothat the feeler may be brought into contact with the wall of the bore of the barrel, and means for indicating the engagement of the feeler with the wall of the bore.

A machine for calibrating gun-barrels, having means for supporting a barrel, a w1re bearing a .t'eeler and adapted to be moved longitudinally back and forth in the bore of the barrel held by said support, means holding the wire taut, mechanism for imparting relative transverse movement'be-p relative movementgrbetween the barrel supportand reeler, and means for indicating the engagement of'fthe feeler with the Wall of thebore.

4. A inachine for calibrating gun barrels,

having means forsupporting a barrel, a

feeler adapted to be passedlongitudinally into the bore of the barrel held by said support, mechanism for moving the barrel support transversely of the feeler, -and means for indicating the engagement of the feeler With the Wall of the bore of the barrel on the support. m t, t

5. A machinefor calibrating gun barrels, having means for supporting a barrel, a

feeler. adapted to be passed longitudinally into the boreiof the barrel held by said support, mechanism for moving the barrel support transversely-or the feeler so as to cause the feeler to engage with the wall or the bore of the barrel, means for indicating the engagement of the feeler with the wall of the bore, and mechanism for showing on the exterior the point of contact of the feeler with the wall of the bore, said mechanism being connected to move longitudinally of the barport, mechanism for moving the barrel support transversely of the .feeler, mechanism for measuring the amount of transverse movement of the barrel support, means for indicating the engagement ofthefeeler with the wall of the bore, and mechanism for showing on the exterior thepoint ofcontact of the tt'eeler with the wall of the bore, said mechanism being connected to move longitudinallyof the barrel with the feeler.

7 A machine for calibrating having means for supporting a barrel, a wire bearing an electrical contact adapted to be passed into the bore of a barrel, means for the relative sidewise movement of the wire and barrel, and electrically excited means arranged to indicate engagement of said contact with the wall of the bore of a barrel.

8. A machine for calibrating gun barrels, having means for supporting a barrel, a Wire bearing, an electrical contact adapted to be passed longitudinally through the bore of a barrel, means for the relative sidewise movement of the wire and barrel, and electrically excited means arranged to indicate engagement of said contact with the wall of the bore of the barrel.

9. A machine for calibrating gun barrels, having means for supporting a barrel and moving the barrel transversely to its axis, an electrical contact adapted to be passed into the bore of the barrel, and electrically excited means arranged to indicate engagehaving means for for supporting a barrel, a l

gun barrels,-

bore of thebarrel. V e

10. Amaehine for calibrating gun barrels, having means for supporting a barrel, mechanism for movingthe barrel support transment of said contact with the wall of the versely with relation to the axis of the barrel,

mechanism for measuring theinovementof the barrel support, an electrical contact adapted to be passed into the bore of the .barrehand electrically excited means arranged to indicate engagement of said contact with. the wall of the bore of the barrel. A machine for calibrating gun barrels,

havingmeans for supporting a barrel, an electrical c1rcu1t, a contact connected in sa1d c rcuit and adapted to be passed longitudinallyfinto the bore of a barrel, and an electrical lamp 111 sa1d circuit adapted to be Tshunted by the engagement of said contact withthe wall of the bore of the barrel.

12. A machine for Calibrating gun barrels, supporting a .barrel, an endless wire bearinga contact adapted to be passedthrough the bore of the barrel located on the support, means for supporting the wire and means for indicating engagement of said contact with the wall 01 the bore of the barrel.

13. A machine for calibrating gun barrels,

having meansfoi' supporting a barrel, an

endless wire bearing acontact adapted to be passed throughthebore of a barrel located on the' supp ort, meansfor supporting the Qwire,meansidetaphably retaining one end or the wireso that it may be detached and passed through the bore of the barrel, means for tightening the wire after it has been passed through the boreof the barrel, and means for indicating the engagement of said contact on the wire with the wall of the bore of the barrel.

V p 14; A machine for calibrating gun barrels, having means for supporting a barrel, an endless Wire adapted to be passed through the bore of. a barrel located on the support, means for supporting the wire, an electrical circuit, a contact connected in said electrical circuit fastened to said wire, and a lamp in said circuit adapted to be shunted by the engagement of said contact with the wall of the bore of the barrel on the support.

15. A machine for calibrating gun barrels, having means for supporting a barrel, a wire bearing a contact adapted to be passed through the bore of the barrel located 011 the support, a Wire bearing an indicator adapted to extend along the exterior of the barrel located on the support, means for supporting the wires, means connecting the ends of the wires, one end of the contact wire being detachably fastened to said connecting means so that it may be detached and passed through the bore of the barrel, means for retaining the indicator Wire taut when the contact 'Wi'reis released, and means, forindieating the engagement of'th'e contact With the Wall of the bore of the barrel.

' "IS. A machine forcali'brating gun barrels,

having meansfor' supporting a barrel, a pair of pulleys with electrically insulated peripheries rotarily mounted on top of the machine, a pair of endless Wires passing around said pulleys, one Wire bearing a contact'and the other ire'b'earing an indicator that shows the "position of the contact, and "an electrical circuit connected with "the con- "tact Wireand adapted 'to be grounded Whenever said con'tact engages the Wall of the bore of "the barrel.

1'7. A machine for'calibrating gun barrels, having means for supporting a barrel, a pair oi' pulleys rotarily mounted'on top of the machine, means for adjusting one pulley transversely of "the barrel support, means for adjusting the other pulleylongitudinally of the barrel support, an endless Wire passing around the pulleys, an electrical contact carried'by said wire,and an electrical'circu'it connected with said 'Wireand adapted to be gldllllded Whenever said contact engages the Wall of the bore'of the barrel. I 18. A mach ne for calibrating gunba'rrels, havingmeans for supportingaba-rrel, apair of pulleyssrotarily mounted on top of the machine, an endless Wire passing around the pulleys, springs :t'or'drawing one of the pulleys so as to hold the Wire normally taut, means for releasing the spring *tension on said pulley, an electrical contact carried by "said 'WlIG, and an electrical circuit connected with said Wire and adapted to be grounded Whenever the contact engages-the Wall ofthe boreofthebarrel.

Copies of this trade-mark may be obtained I9. "A machine for calibrating gimfbarrels, :having a bed, pulleys mounted to rotate on the bed, a Wire extending from pulley to pulley and supported thereby, a contact carr ed by the Wire, an electrical circuit including a lamp With *ohetermina'l electrically connected with the Wire and another terminal electrically connected with the bed.

'20.'A machine for calibratinggun barrels,

having a bed, pulleys rotarily mounted on having 'a bed, a pulley 'rotarrly mounted upon and "movable forward and backward-of the 'bed, means for {adjusting the-pulley toward the front and' back, asecond pulley V rotarily mounted on and movable sidewise of the bed, means for adjusting the'latter pulley sidewise along-the bed,'a contact Wire extending from pulley to pulley and suppol-ted thereby, springs connected With the side-Wise movable pulley "for keeping the Wire taut, and means 'forreleasin'g the tension ofthe sprlngs.

'22. A machine for calibrating gun barrels,

"having means for supporting. abarrel, a pair of pulleys "rotarily mounted on top of the machine, means for adjusting one pulley transversely of the barrel support, an endless wire passing around the. pulleys, an

electrical contact carried by said ire, and "an electrical circurteonnected With slaid contact and adapted to *be grounded Whenever said contact engages the wall of "the bore of thebarrel.

CHARLES W. SPONSEL,

for *fiye cents each;by afldressingthe Commissionerol-Patents, Washington}2\')."(2." I

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