Aluminium tubing for telescopic support

[irving2008]

@FF: Yes, I'd already looked at AW but as you say, long lengths :( I only need 600mm or so of each size. Been looking in eBay for offcuts but nothing suitable seen so far. Also there's no info on size tolerance so hard to tell if one fits inside the other or how well. Yes it would be possible to skim the outside of the inner tube, tho not many have a lathe that can do 600mm between centres on a 50mm tube. Not sure how you'd skim the inside on that length as you implied.

The steel tube/rod approach as drawn has the advantage of a simple welded/bolted construction. Large dia aluminum tube will need a 'plug' of some sort thus adding to the cost. Also there are plenty of examples of 20mm steel rod and 25mm x 2.5mm steel tube on eBay.

Now I've done the c of g calcs the foot can be reduced to 500mm long and 500mm wide (from 700 x 650 as drawn).

[quickcut]

If you wanted oval tube , why not take round tube and squash it in a press brake?