Quote:
Originally Posted by Sunfish
The weight of the 1.1 m .225m ss section including the collar is around 7.5 kg , a little heavy but if only 700 mm was used for an f4 that would equal 4.7kg for the tube alone less the penetrations.
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1mm is a bit thick. stainless has lower yield stress than carbon steel. I have a 0.55mm straight seam galvanised steel tube on my dob, $27 from the local duct shop. now locally reinforced at the focusser by riveting a ring of 5mm flat aluminium.