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.

There is an art, or rather a knack to flying.  The knack lies in learning how to throw yourself at the ground and miss.  ~Douglas Adams, Hitchhikers Guide to the Galaxy

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

Thanks for that, I ordered up the tubes.

you were sure right when you said they didn't really need any sanding, although i'm pretty sure that they would have worked straight out the box I literally spent no more than a minute with 1500 wet and dry and they slid together really smooth, thanks for your help so far

Steve.

There is an art, or rather a knack to flying.  The knack lies in learning how to throw yourself at the ground and miss.  ~Douglas Adams, Hitchhikers Guide to the Galaxy