Re: Help with an Apparatus

[brian whatcott <inet@intellisys.net>]

At 13:47 5/25/97 -0500, you wrote:
> I have a wall mounted apparatus that I would like to rotate to various 
> positions and stay put after letting go.  I have heard of a teflon 
> bearing that is used in Dobsonian telescopes.  Anyone know more and where 
> I can get these materials.  Thanks in advance.
>
> ----------
> Tom K. McCarthy   Email:mcca6300@spacelink.msfc.nasa.gov
Last weekend, in compliance with my wife's wish to reach out on FM
to gather in a distant Dallas station, I was musing on the virtues
of lead compound wall anchors for fixing antennas on brick walls.

 I recalled that after several blow-downs the Eddystone lighthouse 
structure was fixed to the rock substrate in a similar way.
 A hole was drilled; each hole was filled with hot wax, then the wax 
replaced with hot lead compound, which then held the fixings in 
place through a following century of storms.

 These lead plugs cost around 20 cents each,  depending on size;
an authentic bargain.

I notice that surveillance TV cameras often sit on wall mounts
with a pan and tilt head of sorts.
 And a pan and tilt is to be found in any camera store.

But I have in the workshop a machinist's angle vise which 
handily rotates through 90 degrees and will handle significant 
loads. It cost under $30.  These are among the many engineering 
goods lately flooding in from China.

The preceding discussion was about fixing things that rotate
to walls.

  But in reviewing your question, I see there is a wish for 'move
then let go'. This often calls for a counterbalanced pivot.
    Amateurs have long coveted robust telescope equatorial mounts 
of the English and German types - and these are to be found at a price 
in the pages of the Astronomy /Sky & Telescope type magazines.

In connection with PTFE bearings, it is quite possible to buy this
 material to have machined to suit through the regular plastic 
suppliers.

 And at this point I expect I have already related more than 
I know...
Regards



brian whatcott <inet@intellisys.net>
Altus OK