telescopic tubes

I'm in the early stages of designing a piece of furniture that has a single column suspened from the ceiling. It must adjust vertically
carry ~100 #'s ecentrically and have as little play as possible and be inexpensive to make. I'm thinking of using 2.5" x 2.5" x .125" square tube female & 2" x 2" x .125" male. My local steel providers don't provide anything with closer tolerances how do i take up the slack. I remember seeing a piece of weight lifting equipment use a kind of teflon tape as a type of anti friction / shim. Any ideas would be appreciated. www.ironworkx.com
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I would consider the following:
1. Use 2" pipe inside of 2 1/2" pipe. By getting thick wall pipe, and getting the inside machined out you can get the size you need.
2. Use 2" * 2" square, and manufacture the outside (female) square tube from 4 flat bars. The first one is a bit tricky, but after you figure out how much "bigger" to make it, to allow for shrinkage and distortion, it gets easier :-). It may seem like a bit of work, but it isn't as bad as trying to find two bits of square tube that telescope satisfactorily.
Wayne Posted and emailed
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Vittorio wrote:

Is this like a pole lamp - supported by pressure against floor and ceiling? How eccentric? I.e. how long is the arm carrying the 100# load?
Ted
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What's a pole lamp? It's not a lamp it's a 17" hdtv carrage that rides on two ceiling tracks.As of now the load is concentric & the telescopic arm is 60"
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