Looking for telescopic box section steel

Looking into a collaborative build of a few units from an American set of plans.

Plans call for 4" x 3" and 3 1/2 " x 2 1/2" rectangular box sections of 1/4" wall thickness. Build video shows these telescoping inside each other after the projecting weld seam on the larger section has been removed.

I'm not totally surprised that imperial rectangular box can, apparently, no longer be obtained off the shelf. But I am surprised that there is no near equivalent pair of metric sizes around. Nearest I can find is 5 mm wall square box in 70, 80, 90 and 100 mm sizes.

Is this lack really the case or am I just looking in the wrong places. I'm going to need about 2.5 m of the large one and 2 of the small one. More if more folk come on board.

I can re-jig the design so the square tube works, it has to be metrificated anyway and I need to generate drawings for the laser of water jet cut parts, but rectangular box is a more appropriate shape for the job and style. The idea of welding up a non standard size from channel or angle doesn't appeal.

Clive

If you could thin it down a bit Parker Steel list 90x50 and 100x60 in 5mm wall, don't know how tight they would actually be,

Could be pricy for small amounts from them, but its available

Edited By JasonB on 12/12/2021 20:54:27

I have some bits of hollow steel beam which were off-cuts from a house extension nearby a few years ago....I don't know the exact internal dimensions and I'm not going down the workshop on a night like this,...however I do know the wall thickness is 6mm and that there is/was a steel section to fit inside this, although to what accuracy I don't know. The corners of the tubes are rounded and the tube was used to support the extra staircase to a roof apartment

..........Go to a good architectural steel supplier and ask there!

Thanks Jason.

Doesn't have to be super tight fit just no rattle.

The Parker steel size is a bit too skinny I think. I'll see what it looks like when I draw it out. The original has a 1 3/4" diameter part going down inside the 3 1/2" x 2 1/2" . I suspect that by the time I've re-sized everything it's just not going to work unless I re-scale the whole thing which will make it all too small.

Hafta say I didn't find the Parker website easy to navigate so I'm not surprised I missed it. Not my favourite supplier as we have a "history".

Clive

Bob

Your suggestion to investigate architectural steel suppliers looks promising. More around in this neck of the woods than I expected.

Thanks

Clive