Re: Commodore 1520 supplies + programs

On Tue, Jun 24, 2014 at 4:06 PM,  <silverdr@wfmh.org.pl> wrote:
> On 2014-06-24 at 16:41:23, Ville Laustela (ville.laustela@gmail.com) wrote:
>> I recently bought a Commodore 1520 plotter printer from eBay. I was lucky: none of the
>> gears were split
>
> You were lucky, indeed. I have several of those and ALL have the same failure: this tiniest gear on the axis of the stepper is broken and split.

Indeed.  I have a printer or two and a small box of surplus printer
mechanisms (from Electronic Goldmine 11 years ago), and nearly every
motor gear is split.

> Kiitos! I need to find one day a source of those damned tiny gears or I print them one day myself ;-)

(and as we do every few years... here's the "make new gears" thread,
but hopefully with a modern twist...)

With the proliferation of laser cutters and CNC machines, have we
progressed to the point where "we" can feasibly make these at home?
I've done a bunch of 3D printing (with filament and resin), but
perhaps a machined Delrin gear or a sintered plastic gear (from
Shapeways, perhaps?) is feasible?  One thought is to 3D print not
individual gears but a long (2" to 3" or maybe longer) and slice it
into individual gears.  Shapeways charges by the cubic centimeter plus
a per part handling charge (the last time I looked) so if single print
could be made into multiple gears, that might make it cost effective,
presuming the sintered plastic was strong enough.  They also do metal
at a higher cost, but I'd be worried that a metal drive gear would
chew up the next gear down the line.  Laser-cut Delrin would also be
somewhat inexpensive.  It should only take a couple of minutes to cut
out something that small, and a few trials should establish what
mathematical dimension (scaling) is needed to accommodate the kerf of
the laser.  I have access to a 60W laser that rents for $35/hr, and I
know of other hackerspaces that have laser that bill out at $1-$2 per
"laser minute" ("on" time).

-ethan

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