Kristinn ... here is what I would use ... FINGERSTOCK
http://www.surplussales.com/RF/RFFingerstk-1.html
----- Original Message -----
From: "Kristinn Andersen" <tf3kx@simnet.is>
To: <towertalk@contesting.com>
Cc: "'Kristinn Andersen'" <tf3kx@simnet.is>
Sent: Saturday, May 07, 2005 6:37 AM
Subject: [TowerTalk] Making aluminum tubes telescope smoothly,with good
electrical conductivity?
> Hi:
>
>
>
> I am working on an extensible vertical consisting of a 6m/18ft outer
> aluminum tube (40mm/1.5" diameter) and an inner aluminum tube that can be
> extended out of it with a motor mechanism. For certain reasons the inner
> tube has to be substantially slimmer than the outer one, probably around
> 25mm/1" diameter. So, to make a reasonably tight fit I will make a
> narrowing "collar" at the top of the outer tube, where the inner one will
> emerge upwards. Furthermore, at the bottom of the inner tube I will
> fasten
> a cylinder that almost fills the outer tube, providing mechanical
> stability
> there. Sort of like a piston inside the outer tube. Thus, the mechanical
> connections or interfaces between the outer tube and the inner tube are at
> the top of the outer tube and at the bottom of the inner tube. At these
> key
> points I need to ensure:
>
>
>
> a) Good electrical contact (so that antenna currents can continue
> from
> the outer tube to the extended inner tube;
>
> b) Minimal mechanical friction as the inner tube is pushed up and
> retracted back down.
>
>
>
> Are there any suggestions on this? What metal should I use that slides
> with
> low friction against the aluminum tube wall, does not corrode at the
> contact
> and provides good conductivity?
>
>
>
> 73 - Kris, TF3KX (http://www.simnet.is/net/tf3kx)
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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