Hi, I've been looking at the pultruded tubes and box sections as a want to make a wing spar using them but i want to be able to slide a centre tube inside two others if you get what I mean. so all I need to know really is; will a 10mm od tube slide into a 10mm id tube? or are the tollerences not accurate enough to allow this?

Thanks, Look forward to a reply, Steve.

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Hi Steve,

With the tubes being in theory size and size, the tollerances can cause issues, the round tubes will normally slot into one-another however they are often very tight, to get a good slide fit you would be best sanding the inner tube slightly with 1200grit until it was right, this shouldn't take too much doing though. it is worth saying that somtimes you can get lucky and get an inner tube that is at the lower end of the variation and an outer tube that is larger, in which case you may get a perfect fit from the start.

The square tubes are slightly different as they have rads in the corners and you get slight pull on the wall, you would need to do a reasonable amount of tweaking with wet and dry to get them to telescope fully and easily.

I hope this helps you out,

Paul Statham
Easy Composites / Carbon Mods - Technical