Make a Threading Tool For the Lathe

Here's a good video by Tubalcain about shaping a single point lathe threading tool:

http://youtu.be/HTQ46NMMc88

Tool Grinding In a Pinch

Lately I’ve been working on a bunch of small, round lens-holder parts that have somewhat complex inside contours with multiple ledges and inside chamfers at tight tolerances. I needed a sturdy lathe tool to reach inside a bore and cut a 1/8” chamfer on the corner of a ledge. My small boring bar would have been perfect, except that I had made the nose so sharp. I needed the sharp nose for making sharp inside corners but that pointy nose also made a very rough surface on the chamfer. A second tool with a rounded nose was what I really needed.

Rather than make a trip to the tool store or order another boring bar online, I ground a suitable tool from square HSS tool stock. It took about 15 minutes out of my day and is just as functional as a fancy, round boring bar.

 View of cutting edge.

 Bottom view.

Top view.

Deformation Averted

Here are two “Can’t Twist” clamps holding a cylinder to a faced block of aluminum secured in the vice. The reason for this setup is to prevent the cylinder from being deformed by the clamping force of the vice. There will be two aligning pins pressed into the top end of the cylinder and if it gets deformed while drilling and reaming, then as soon as the pressure is relieved, the holes would no longer be positioned correctly. Downward pressure won’t deform the cylinder in this case.