12 Apr
2013
12 Apr
'13
2:34 p.m.
On Fri, Apr 12, 2013 at 5:59 PM, geneb <geneb at deltasoft.com> wrote:
Ethan, you might try talking to Shapeways or Ponoko
and having the gear
printed out of stainless steel. A very small gear shouldn't cost that much
and may last longer than a delrin part.
I've thought about that, but, if you haven't seen one of these Alps gears,
there is very little material at the bottom of the "teeth", which is why the
gears all split - weak spot combined with either mechanical or thermal
stress. I don't have measurements to quote, but it's only a few hundred
microns of material at most.
I'm not sure what the surface smoothness is of Shapeways printed SS,
but this gear is about the size of a match head with something like
a dozen teeth (think back to the old "slot cars" and the grape-sized DC
motors and the brass gear on them - it's about that size). It's going
to mate with a plastic gear that's smaller than a dime.
There's a very nice gear program here:
http://woodgears.ca/gear/index.html
I own a copy and it produces excellent DXF files suitable for laser cutting.
That's the same website that I linked to at the start of this thread.
-ethan