Itsy bitsy spider chuck

I made a neat little spider chuck. It’s for machining the bolt of the 308AR for accuracy.

A spider chuck allows me to locate the bolt exactly according to the several features that I decide are important regardless of the shape of the part. Since these parts are forged and then machined in very elaborate ways, it’s very difficult to reference and hold¬†typical and easy ways.

This¬†tool is machined from 1.125″ ground 303 stainless steel shaft, 1.5″ long, with 8 stainless steel flat bottom set screws. It fits perfectly inside a cheap 1 1/8″ 5C collet that makes accurate machining very easy on the Hardindge lathe.

Later I’ll make a larger version for working with rifle barrel breeches and muzzles.