Re: ATM Attaching poles

["James Lerch" <jlerch1@tampabay.rr.com>]

You idea is the Inverse of mine, which seems to be working fairly well.

I used a 1/2" steel conduit stuffed into a hole bored into my mirror base.
At first there was considerable friction to get the tube into the hole,
requiring a block of wood to beat the tube in, but now after many
disassemblies I can insert the tubes with just a little "twist and push"
action.  The apex of my tubes are held by a clamp type assembly.

My experience is that the system works amazingly well once assembled, which
I attribute to the following:

#1 The holes bored into the base are just the least bit off from the precise
angle, so when clamped at the apex, a little spring tension is applied to
the truss. (IE the tubes are 5 foot long, and at the apex, they want to
overlap by 1/4")  The spring tension increases the friction between tube and
hole.

#2 The tubes will only move along the axis of the tube, once clamped at the
apex, any motion in the tube will be at some tangent to its axis, thus
friction is increased and the tube stays put (unless of course the tube
under compression should buckle, which I doubt)

#3 The Mirror Base is made From MDF, and a Flat spade bit was used to bore
the 2" deep hole, consequently I have a rather rough interior to the hole,
so perhaps the MDF Fibers are assisting in keeping the tube in place while
under tension.

All I know is that in my experience, I have never noticed a shift in
collimation from the tubes moving in their holes, and since its a bino-scope
any change in collimation would be immediately noticed!

Also I trust the system enough to pick the whole altitude assembly up by the
Truss poles (120 pounds +/-), however I will admit I worry about the MDF
splitting along the axis of the bored hole, but to date, nothing has
happened :)

Pics of all this are on my website, under the proto-type link.

Take Care,
James Lerch
http://Lerch.yi.org/atm