I attempted to cut a pinion gear again, with no luck.

I’m using a 24 pitch 14.5o involute gear cutter on a Sherline gear cutting arbor. I want to cut a 12 tooth gear. I turn a 3/4” round bar stock down to 37/64.

(Teeth + 2) / pitch = Outer Diameter

(12 + 2) / 24 = .5833 ~ 37/64

I then transfer the chuck to the rotary table. I lower the headstock so that the bottom of the gear cutter touches the blank. I then divide the cutter height by 2, and lower the headstock by that much:

Cutter width = 15/64, half = 1/8.

The radius of the blank is 19/64.

And somewhere I’m off by a 1/64 of an inch which blows the tooth geometry…

I much be sloppy somewhere and am just missing it.