This item is a small clamp to hold a nut while starting it onto a stud when changing chucks on the HF 7×10 mini-lathe. You place the nut flat into the clamp opening, turn the clamp-bolt down finger tight against the side of the nut, and then start the nut on the stud as described below.
When holding a nut, the clamp is thin enough to fit between the headstock and the back of a stud.
Place the nut to be started into the slot of the clamp and tighten the clamp-bolt to hold it in place. Rotate the lathe spindle until a stud of the chuck is near the top front corner, to provide maximum swing for clamp rotation. With a springy strip or thin screwdriver blade between the headstock and the clamp, lightly force the clamp and nut against the stud.
Picture above illustrates this. Now rotate the clamp through a wide arc to engage the nut onto the stud, remove the clamp, and finish tightening the nut. Materials needed:
- 1 ea. 5/16″ square steel bar, 1.5″ long.
- 1 ea. #10-32 bolt, about 2.5″ long.
- 1 ea. #10-32 nut.
- 1 ea. 1/2″ round steel bar, about 5/8″ long.
See “plans” in picture above.
The clamp body is 5/16″ (0.3125″, or about 8mm) square by 1.5″ long. (This bit of 5/16″ square was sawn from 5/16″x1.5″ bar stock.) I first drilled a .188″ #10-bolt clearance hole 1/2″ deep and then drilled through with a .162″ bit (tap drill for #10-32). Then I cut a recess .4″ wide by .2″ deep (slightly larger than the 10mm wide x 5mm thick 6×1 metric nut) near one end of the clamp body, leaving about 1/8″ of metal behind and below the recess.
(The finish on this clamp would be better if I had cut the recess with an endmill rather than filing it out, but it works ok anyway.) I tapered the sides of the recess and the clamp end for better clearance, thus allowing the nose of the clamp to clear the spindle below the stud.
I threaded the 0.162″ hole in the clamp body to receive the #10-32 bolt. At the head of the bolt, I added a short length of .5″ round, drilled through .188″, to act as a knob. I fastened this with a nut, but a knob could have been threaded on or brazed in place.
Author: James Waldby