Re: Commodore 1520 supplies + programs

On 2014-06-24 at 22:17:18, Ethan Dicks (ethan.dicks@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 wrote "one day" I'll print them myself. By that I meant that home-based 3D printing is not there yet. And even professional services like Shapeways don't offer precision high enough for this kind of things.

> 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.

The material is one thing - I guess this could be chosen properly. The problem is with accuracy. You can do some "toy type" of gears there but for true precise mechanics it is not there yet.

> 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.

I bet so. Especially a printed one.

> 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).

That's probably the only viable option as of today.

--  
SD!

       Message was sent through the cbm-hackers mailing list