[ATM] need help with an altitude bearing problem

[Curt Diggs]

One method I've seen used on low friction bearings (metal / teflon, ball bearings, etc.) is to place felt pads between the bearings so that the moving surface also rides against the felt. Adjust the size and thickness to get the right amount of drag. On a highly polished surface I would think almost any sort of smooth felt would do.
   
  Curt Diggs

  Date: Sun, 05 Aug 2007 04:34:11 -0500
From: RP 
Subject: [ATM] need help with an altitude bearing problem
To: atm at atmlist.net
Message-ID: <46B59993.2010508 at suttonsonline.us>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

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



       
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