1520 plotter (was RE: Your VIC-20 is worth $300!!! W_at_W!)

From: Feldman, Robert <Robert_Feldman_at_jdedwards.com>
Date: Thu Jan 31 08:58:45 2002

A good model railroad hobby shop (or a major suppliers like
www.walthers.com) will have mould making and resin casting kits. Some of the
current casting resins should be strong enough to use as a gear. You can
make an open mould, pour the resin, then put a glass plate over the open
side to smooth the casting, or just sand it smooth when it has cured.

Another thing to try would be to make a mould from dental plaster or
Hydrocal (a harder-than normal plaster of paris, available at hobby shops),
then heat it and open cast with a low melting point metal. What I would do
here is make the mould double-deep, then file the resulting casting to the
correct thickness.

Bob

-----Original Message-----
From: ard_at_p850ug1.demon.co.uk [mailto:ard_at_p850ug1.demon.co.uk]
Sent: Wednesday, January 30, 2002 4:07 PM
To: classiccmp_at_classiccmp.org
Subject: Re: 1520 plotter (was RE: Your VIC-20 is worth $300!!! W_at_W!)

<snip>

> > There seem to be several possibilites :
> >
> > 1) Make a mould and injection-mould them yourself. I think the David
> > Gingery injection moulding machine could easily do it, but the mould
> > would be very hard to make (cutting internal teeth on a mould that size)
>
> Might not produce a clean casting, either.

I bet the originals were moulded rather than machined.... Maybe then
cleaned up by machining, though, but I doubt it, actually. The original
gears are not that good quality.

<snip>
Received on Thu Jan 31 2002 - 08:58:45 GMT