Aluminium tubing for telescopic support

[irving2008]

Hi all

Trying to find aluminium (or steel if I must) in sizes where one bit fits neatly inside another and can be locked in place with simple clamp - think bike seat-tube into frame, but bigger, say outer tube 45 - 60mm dia, 4 or 5mm wall, if ally, 35 - 40mm, 3mm wall if steel.

Ideally, from an aesthetic point of view, i'd prefer oval tubing say 60mm x 30mm OD in ally but this seems like hens teeth...

My google fu isnt delivering today :(

Any ideas?

[WandrinAndy]

How about the aluminium tube that is used for tall "portable" radio masts? Although I would imagine they might have a thinner wall size than 4-5mm.

Btw, what on earth is "google fu"?

[Greeny]

I just came across this afew days ago , i think it's what your after

Buy Telescopic Aluminium Tube online at Metals4u
Edit: On second look they might not be big enough

Here does bigger but not the clamps (just jubilees)
Plain End - Antenna Engineering | Supplier of High Performance Amateur Radio Products


Cheers
Greeny

[irving2008]

Thanks both, the antenna mast stuff is on the right lines, but the 1.5mm wall thickness is too thin, even using the 60mm (2.375") size will deflect too much for my purpose, needs 3mm or more :(

'google fu' is the ancient Chinese art of getting the right search term! :D

[phill05]

what about 25.5mm dia with a 3.175 thick wall, what length & qty are you wanting.

Phill

[Greeny]

Cant find anything of those sizes

All I can suggest is
2.125 + 2.250 + tube of epoxy
2.375 + 2.500 + tube of epoxy

Massive contact area, so would be a very strong bond

[irving2008]

Cant find anything of those sizes

All I can suggest is
2.125 + 2.250 + tube of epoxy
2.375 + 2.500 + tube of epoxy

Massive contact area, so would be a very strong bond

Ummm... But they do need to slide... And epoxy won't stop them bending under load!

[irving2008]

what about 25.5mm dia with a 3.175 thick wall, what length & qty are you wanting.

Phill

Thanks, but not strong enough and I need two tubes... The need is to provide a height adjustable support for a ~15kg load with a deflection less than 4mm when the support is at a 15degree angle.

[phill05]

What if you had a steel rod of say 19mm dia as the sliding part down the bore?

[irving2008]

What if you had a steel rod of say 19mm dia as the sliding part down the bore?

That might work. A quick mental calc says about 4mm deflection at 1m with 600mm of rod in a 600mm tube (ie min height would be 600mm). I need to do more accurate bending calcs and torsional calcs as may allow too much rotation Weight is about 2.9kg. Only downside is a 1" pole looks aesthetically 'flimsy' lol