(No Model.) 7

'J.. MARTIGNONI.

MACHINE FOR CUTTING HELIGAL enoovss INTWIST DRILLS. .No. 270,235. Patented Jan. 9.1883,.

N. "ETERS Pnalo-Lilhegmplvun \Vnshinglon. n. c

I UNITED STATES PATENT OFFICE.

JQHANN MARTIGNONI, OF BOCKENHEIM, NEAR FRANKFURT-ON-THE-MAIN, GERMANY.

MACHINE FOR CUTTING HELICAL GROOVES iN TWIST-DRILLSI SPECIFICATION forming part of Letters Patent No. 270,235, dated January 9, 1883.

Application filed September 20, 1882. (No model.) Patented in Germany January 27, 1882, No. 2,035; in Belgium January 28,

1882, No. 56,917; in France February 17, 1882. No. 147,412, and in England July 17, 1882, No. 3,384.

R gearing into the wheel R. On the same 5 To all whom it may concern Be it known that 1, JOHANN MARTIGNONI, of Bockenheim, near Frankfort-on-the-Main, in the Empire of Germany, have invented a new and useful Lathe Attachment for Outting Helical Grooves in Twist-Drills and Similar Objects, (for whichI have obtained patent in Germany, No. 2,035, hearing date 27th J annary, 1882; in Belgium,No. 56,917, bearing date28th January, 1882; in'France, No. 147,412, hearing date 17th of February, 1882, and. in

England a six months provisional protection,

No. 3,384, bearing date 17th July, 1882,) of which the following is a specification.

The apparatus which forms the object of my invention serves to cut twist-drills, reamers, screw-taps, and similar objects having helical grooves, and may be attached to an ordinary lathe. Its construction will be explained with the aid of the accompanying drawings, in whicha Figure 1 is a plan of a part of a lathe provided with the attachment, while Figs. 2 and 3 are respectively a side view and a front view of a cutting-tool.

The frame A A of the apparatus is fixed to the upper or cross slide of the lathe. The frame carries an adjustable screw, 0, and a driver, D, with triangular extremity, forming a center, between which and "the center of the screw (J the piece of work is mounted.

Opposite the piece of work is placed the pe-- culiarly-shaped cutter f, secured to the mandrel by means of a chuck. The object to be grooved is approached to thecutter f by turnin g the handle M of the slide.

The required helix is produced by a slow longitudinal and simultaneous slow rotary motion of the piece ofwork by means of the following mechanism The pin D, which serves as a driver, carries at one extremity a bevel-wheel, R, and the contiguous end of the frameAAforms a forked bearing for the horizontal shaft W, on which are mounted the bevel-wheels R and shaft is keyed outside the bearings a spurwheel, S, which gears into a rack, T, bolted to the lathe-bedparallel to the piece of work. If the handle N is turned in order to move the lathe-slide so as to obtain a longitudinal [HO-'1 tion of the piece of work, the pinion S, which gears into the stationary rack T, is forced to revolve, and transmits this motion to the bevelwheel R by means of one of the bevel-wheels R and R mounted on the shaft W. Thereupon the wheel R turns the driver D, and consequently also the piece of work, on its axis. For cutting a right-hand helical groove, the right wheel R and for cutting a lefthand groove the left wheel R, is screwed fast on its shaft, while the opposite wheel is loosened.

- In order to render the helical groove more or less steep, the piece of work must be turned more rapidly or more slowly, which is effected by changing the spur-wheel S.

For producing straight grooves, the screwcaps, and subsequently the pinion S, is detached from the shaft W,\vhile the rack T may or may not be detached from the lathe.

Having thus described my invention and the manner in which it maybe used, lclaim- The combination, with the cross-slide of a lathe having the piece of work fixed thereto, ofa driver, D, with bevel-wheel R, bevel-wheels R R and pinion S, a rack attached to the lathe and gearing into thesaid pinion for the purpose of producing a rotary motion of the pinion, driver, and piece of work when the crossslide of the lathe is moved, substantially as described and illustrated.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.