The accompanying drawing suggests a method of converting an old lathe or speed lathe into a screw-slotting machine.

Fig. 148 - Screw-slottiug attachment for lathes.

The angle plate A is secured to the bed of the lathe. In the vertical face of angle plate A is a dovetail groove, in which angle plate B fits, so as to afford an up-and-down motion. On the top face of angle plate B is a dovetail groove, in which slide plate C operates. Lever D pivots on swivel E, giving movement to slide plate C. Place the screw to be slotted into draw chuck F, and tighten on draw wheel G. With the fixture so placed on the lathe bed as to cut the screw centrally, the depth of the slot may be regulated by adjusting screw I. By moving the lever D, the screw is fed into the saw H. There is an elongated slot J in the-angle plate B to allow the draw clutch to pass through and move back and forth. In angle plate A is a stud K to hold in position the adjusting screw I.

By a little practice the screws may be slotted very rapidly.