Gear Cutter terms

I asked the leaderman of our gear department and he has never seen a hob with a "T" inside a triangle. 22dp is quite a bit finer than we normally work with, but we go through quite a few hobs. It might be an identifier mark for the hob manufacturer.

As far as the d+f, Ash Gear & Supply shows 2.157/dp as an old standard depth (2.157/22 = .098) and the current standard as 2.25/dp (2.25/22 = .102). They also show that 20dp and finer has a dpeth of (2.20/dp)+.002. The .100 depth works for 2.20/dp.

When you say the cutter is "thinner" are you referring to the flutes? They might be thinner if the hob is older and has been resharpened more than the other hobs.

I'm not a hob expert, but I hope this helps