mlcorson wrote:

I need to construct something that will slide occasionally inside a
2.5"x1/4" steel tube. I want to use a 2"x1/4 to fit inside a 2.5"x1/4"
Do they fit? I've only got piece of 2.5" to measure at the moment. In
theory looks like it will.
The length is approx 36", and the lenght of slide is only 5-6". I'd
like it to be a close fit but not too tight as it might bind. It's
going to be part of the frame of a 2"x72" belt grinder. Where the main
frame holding the axle will extend or contract depending on the grinder
attachments.
-Mike


I doubt it. Such tubes are welded, and there is a weld bead on the inside, and
this is usually the main problem with telescoping tubing. You can buy
telescoping tubing, but of course it costs more money than regular square tube,
which is itself pretty pricey these days. What I recommend is to carefully fit
pads of 1/4" steel inside e.g. 3" square tube, just to make a rim around the
inside edge. This can be ground to fit over the bead, and welded on the end, and
the pad can be filed or otherwise shaped to just fit e.g. a 2" square tube. The
inner member should have a similar pad put on its innermost end, but on the
outside. This will make it ride straight, and will keep it from ever coming out.
You don't have to fit the pads perfectly in the corners. This is how they make
telescoping arms for boom trucks, and it works great.

GWE