On Mon, 08 Sep 2008 10:37:12 -0700, JR North
wrote:

Have a project, need a gear for a stepper with .187" Dia D shaft. I can
make the gear; are there broaches for forming the pilot bore? Seems
there would be a bazillion different ones, depending on the width of the
flat.
Else, how to?

A set screw is the only reasonable option if you want to use the flat,
but I don't blame you for looking for something better. The $30
solution is a Trantorque coupling -- see McMaster 5926K11. A much
cheaper option (about $2) is a 3/16" clamp collar screwed to the face
of your gear and tightened on the shaft. McMaster 6435K51

--
Ned Simmons