Here’s a drill bit I modeled. Mostly as a modeling exercise, but also to learn more about drill geometry. Drill bits are a bit more complicated than I expected. In particular, the *chisel angle* and the *cross-section* of the *flutes* are not immediately obvious and can be mathematically complicated (especially the flutes).

Anyways, don’t take the facet angles too seriously. Some angles are close to correct (30 deg helix angle, 8 deg clearance angle, approx 120 chisel angle, 135 deg point), others are just eye-balled.

I might try to create a guide for drill-bit sharpening, but I doubt I would come up with anything better than a Darex, Tormek, or Drill Doctor. But maybe some guide that could be 3d-printed for a silly hobbyist maker, like myself.

Maybe useful as a teaching tool for those learning to become machinists.

Drill Bit Geometry.stp (3.5 MB)