12 Apr
2013
12 Apr
'13
2:52 p.m.
On Fri, 12 Apr 2013, Ethan Dicks wrote:
Ah, didn't see that.
g.
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On Fri, Apr 12, 2013 at 5:59 PM, geneb <geneb at
deltasoft.com> wrote:
Well you might want to replace the tiny pinion gear with a larger one and
reduce the size of the gear it mates to. As long as you've got the space
and can keep the ratio the same, you should be fine.
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.