[ATM] need help with an altitude bearing problem

[Dale Eason]

I am surprised that no one has given you the tried and
try solution.  That is to use ebony star Formica in
place of the metal riding on the Teflon.  You can
easily glue Ebony Star strips onto the stainless
steel.

The secret is that Ebony Star has a bumpy surface that
increased the sticktion.  For some reason I don't
understand, many inexperienced dob makers think that
you want a low friction bearing.  As you have
discovered that is not the case.  What you want is
something with high stiction and then low friction as
you start it moving.  Ebony star and Teflon were found
to have this characteristic many years ago and almost
no other combination is as good.

Ebony Star seems to be harder to find these days.  If
you can not find Ebony star, then look for some other
material with a similar rough surface.  There is
another material but I can't remember exactly what it
is.  I'm sure others will remind me.

Dale Eason

--- RP <rp at suttonsonline.us> wrote:

> Hello Everyone -
> 
> I have a telescope that was made for me by a friend.
> The altitude 
> bearing surfaces are highly polished stainless steel
> against Teflon. 
> This results in extremely smooth motion with hardly
> any "stick-tion" at 
> all. This makes the scope very sensitive weight to
> changes at the ep and 
> difficult to counterbalance (ie, a counterweight
> that will keep the 
> scope from plunging downward when I add a 2" ep will
> also cause the 
> scope to swing toward the zenith once I pass the
> midpoint going 
> upwards). The bearing consists of an 8" diameter
> stainless steel "ring" 
> riding on 2 Teflon pads. I am trying to come up with
> something else to 
> use in place of the Teflon that would add a little
> drag to the system. I 
> was thinking of using a plastic that is maybe not so
> smooth as Teflon? 
> would pads made out of delrin or a similar hard
> plastic work? I have 
> been told the best solution would be to redesign the
> bearing assy 
> completely, but I have limited skills and even fewer
> tools. Any ideas 
> would be greatly appreciated.
> 
> Thanks -
> 
> RP "Patrick" Sutton
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 



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