Re: What do we want?

>Message: 2
> Date: Tue, 19 Oct 1999 23:50:01 +0100
> From: "Ian Wright" <Ian@...>
>Subject: Re: Re: What do we want?
>

[Actually, I mis-spoke (or mis-wrote) The drive on my mill's screws isn't a
steel roller-chain, like on a bicycle- it's a toothed rubber belt which
engages a corrugated pulley. This would be closer to the "pure curve" you
mention, but I'm not sure if they are accurate over long distances. It does
seem fairly positive over the short (6" between centers) distance. Has
anybody seen or heard of a router driven with one of these- not using it to
drive a ball-screw, but actually attaching the sliding stage to one (or
more) of these toothed rubber belts?]

Andrew Werby

>Hi Andrew,
>
>In theory, a chain drive should be less accurate than a cable as movement
>round the sprockets is not continuous. That is, the links of the chain go
>round the sprocket as a series of straight lines rather than a pure curve.
>Whether the resulting (small) error is significant in your application would
>have to be a part of your considerations.
>
>Ian
>--
>Ian W. Wright
>Sheffield UK
>
>
>----- Original Message -----
>From: Andrew Werby <drewid@...>
>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?
>

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