Re: [ATM] Public Terrestrial Telescope: Focuser Materials & Lubricants?

["Don Clement" <don_clement@charter.net>]

Self-lubricating Turcite http://www.boedeker.com/turcax_p.htm is the modern
day Lignum vitaea and the perfect material for use in a  terrestrial scope
set up in the dusty Bad Lands above San Timoteo Canyon , perhaps you can see
Wyatt Earp's place with it
http://www.arcadiapublishing.com/news_article.html?id=892



Don Clement

Running Springs, California


>
> A bushing or nut made of a self-lubricating material would be ideal, and
> Delrin (aka acetal) immediately comes to mind. But when I do a Google
search
> on the properties of Delrin, I find some references to the effect that it
> shrinks with age. In particular, I found some comments by radio-controlled
> model car enthusiasts complaining that some of the Delrin gears in their
> cars had been press-fit onto aluminum hubs, and that, as the Delrin aged,
it
> shrank and split. Assuming that what they say is true, that would
eliminate
> Delrin.
>
> Of course there's Teflon. But Teflon is expensive, it's very soft, and
when
> stressed, it permanetly deforms, so I'm guessing that a Teflon bushing
would
> gradually loosen with time.
>

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