RE: ATM Speaking of Dob Bearings

["Bertapelle, Ken" <Bertapelle.Ken@tci.com>]

Mike,

IMO, too little friction is one of those problems that is good
to have.  It sounds to me like the problem you should be really
worrying about is the balance of your OTA.  The situation you
want to achieve is one where the scope responds to a very light
touch to move it, but then stays put, with no backlash, when to
take your hand away.  This can only be achieved with low friction
bearings *and* good balance of the OTA around the alt bearing
pivot point.

If you can get a copy of Kriege's book, it contains an excellent
discussion of all this.

- KenB

> -----Original Message-----
> From: Michael Gregory [mailto:mikeg@airmail.net]
> Sent: Wednesday, June 16, 1999 5:24 PM
> To: atm@shore.net
> Subject: ATM Speaking of Dob Bearings
> 
> 
> 
> 
>      I replaced the thin nylon bearings on my Celestron 8 inch
> Dob with Teflon strips.  The other bearing surface on this scope
> is aluminum.  Now there is not enough friction.  I have to adjust
> the sliding counterweight too often.  Anyone have any
> recommendations for modifying the Teflon.  They are currently
> about 1.5 inches long.   Should I just cut them down -- move
> them or what.
> 
> Mike Gregory
> Dallas, Texas
> 
>