Can you use a 200p with just the 1 scope ring

[beamer3.6m]

I want to build a dob mount and am considering the alt bearings.

I am wondering if one tube ring can be used to attach a bearing to.

My question is really would the tube bend or be under pressure with only 1 ring in use.

[Cornelius Varley]

I want to build a dob mount and am considering the alt bearings.

I am wondering if one tube ring can be used to attach a bearing to.

My question is really would the tube bend or be under pressure with only 1 ring in use.

It probably wouldn't bend the tube, but fixing the tube using a single ring can't be a good idea.

[beamer3.6m]

It probably wouldn't bend the tube, but fixing the tube using a single ring can't be a good idea.

Why would it be a bad idea?

[Ricochet]

I would think the tube wouldn't be held in a very stable position by only one ring. Hold a pen between thumb and forefinger and wobble it, you would probably see the same movement with a telescope. If you want to use the rings to mount the tube have a look at this design, you could probably make something similar:  http://www.bresser.de/en/Astronomy/Messier-8-Dobson.html

[Cornelius Varley]

Why would it be a bad idea?

A single ring would only hold the tube at one location, the tube would not be adequately supported and would probably move in the ring unless the ring was sufficiently wide enough to support the tube (clamshell type mounting). Two rings bolted to a dovetail bar will hold the tube with no movement. 

[Moonshane]

I'd use two. Here's one I made a while back from bits in the shed.

http://stargazerslounge.com/topic/105895-home-made-dobsonian-base/?p=1050425