Re: What do we want?

From: garfield@... (Gar Willis)
Subject: Re: What do we want?

On Mon, 18 Oct 1999 20:28:40 -0400, "Clint Bach"
<clintbach@...> wrote:

>I made the gantry out of a reinforced plywood box for rigidity
>have the z axis mounted on 1 1/2 inch electrical channel.
>...
>My router setup is like the Shopbot (tm)on steroids. I
>made y with 60 inches of travel and only made x have 30 inches of travel.
>to expand the beast I only have to use longer rails to extend x and build a
>longer base to put it on.
>...
>The cable drive machine is totally immune to sawdust but the threaded rod
>machine hates sawdust on the threads.

I asked about this, cuz I just KNEW I'd hear something novel and
interesting. I ask this same question of everyone I can that's built a
LARGE format router for this type of wood/foam work, and always marvel
at the diff. schemes people have used. And yeah, the dust from such
material really does seem to be a problem, potentially on both the
positioning mech & the slides.

Anyway, thanks for the word picture. Fascinating.

Gar

[I've been puzzling over this problem myself. One alternative that occured
to me was to install brushes on the ends of the sliders which would sweep
off the screws and surfaces as the machine moved, but this wouldn't be
effective if lubricant was present. I heard Shopbot, which originally used
a cable drive, has discarded it in their later models in favor of a
roller-chain and sprocket drive system. I was considering this myself, for
the router I'm assembling from scratch. Has anybody tried it on any of
their machines? It would seem to be more dust-resistant and robust than
most alternatives, but I'm not sure about tolerances and backlash issues. I
did notice that a roller-chain is used to drive the ball-screws in my old
CNC mill, so in short lengths, at least, it's probably not too bad.]

Andrew Werby

Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com