Re: [ATM] sonotube for telescope

["Bob May" <bobmay@nethere.com>]

Not too sure of what you did for the joints of the octagonal tube but when I
did the tubes for the 200" refractor, I used cherry that was slightly less
than 3/8" thick and cut for a hexagonal tube (30 deg. angle) and butt glued
it together.  Used a long piece of rubber from the cutting up of an
automobile inner tube to hold the wood together when gluing it together.
Afterwords, applying gussets to the joints will insure that there is plenty
of meat to hold the joint together.  Don't use plywood as this won't have
the basic strength to resist the local stresses.
For the octagonal tube, the edges should be cut to a 22.5 deg. angle.  If
you want to be more dedicated to the joint, you can make a piece that will
provide all of the angles, etc. so that the side wood only needs to glue to
it, kind of like a ridgepole for a roof.
I'll also note that the tube won't be very light so be careful with the wood
and so forth so that it will be as light as possible.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net


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