Summary

Thread Borer - Handle Insertion Tool

This object was made for the insertion of 4-40 thread cutters for the purpose of hand-threading through-holes or pilot holes, and comes with a larger piece attached for harder materials that need more torque to cut through.

It is recommended to modify the file as needed and provide a 0.15-0.20 mm offset of your measured mating surface to adapt the design to your own needs.
My boring piece had a width of 2.74, so the offset to the cutout profile it had, created a square with a width of 2.89.