Sharpening taps and dies

It's possible with a Dremel. For dies run a ball stone inside the chip holes, for taps grind the wall of the gullet under the tapered cutting edge with a cylindrical stone.

My surface grinder is a Delta Toolmaker, with a tilting and swiveling wheel head that Prof. Chaddock may have copied:

patent drawings are dated 1942. It isn't the best design for grinding mirror-smooth surfaces, but it's versatile.

I don't have a sliding collet tool holder as nice as the Quorn's so I regrind the taper of large second-hand taps between centers on a swivel table. The resulting flat relief hasn't been a problem so far. It could be done in two steps like an end mill to reduce the relief angle behind the edge but still have clearance.

jsw