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?
JR
Dweller in the cellar

If it's a big cut for the "D", how about milling the hole with a 1/16"
mill. You'll have to go wide on the ends of the flat. It'll be slow,
it'll be hard to do without an NC machine, and it'll look funky, but
it'll put a flat where the flat's supposed to be and put support behind
the shaft where that's supposed to be.

If it's a shallow flat on the shaft, then Mr. Simmons suggestion of a
set screw is a good one. Use the right type -- I only recently learned
that set screws suitable for going against soft round shafts (cup type)
are exactly wrong for going against flats (you want one with a flat
end). The things you learn by hanging with mechanical engineers...

Or make your own broach from O-2 drill rod :-).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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"Applied Control Theory for Embedded Systems" gives you just what it says.
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