Square tubing that fits inside a larger square tubing

[Pcmaker]

I'm planning on making a belt grinder, similar to the one in this picture. I want to know what sizes these square tubings are where I can fit on into a larger tubing

 

[GrifterGuru]

If you can define the belt width, you can work out the square tube size.

Is that a 3" wide sanding belt?

As for sizing the "inner" square tube, that depends on wall thickness of the outer "sleeve" square tubing, since the Inner Dimensions of the main square tube will dictate the Outer dimensions of the sliding "inner" tube.

 

[DavidR8]

That's 99.9999% likely to be a 2x72 grinder.
If you look for online plans of 2x72 grinders you will very likely find the sizes that fit together.

 

[verbotenwhisky]

I'm planning on making a belt grinder, similar to the one in this picture. I want to know what sizes these square tubings are where I can fit on into a larger tubing

Something to think about, you might want to invest in seamless square tubing; otherwise you'll spend a lot of time flattening the seam out inside the tube.

 

[dml66]

I've found McMaster-Carr is great at furnishing dimensions for the metal stock they purvey. In the case of non-round stock, there may be issues with corners; nominally it may appear the two pieces will fit but, the corner radii may dictate otherwise. Square corners may not be as tricky.

 

[Pcmaker]

If you can define the belt width, you can work out the square tube size.

Is that a 3" wide sanding belt?

As for sizing the "inner" square tube, that depends on wall thickness of the outer "sleeve" square tubing, since the Inner Dimensions of the main square tube will dictate the Outer dimensions of the sliding "inner" tube.

It doesn't have to be exact. I'm leaning towards using around 1-1/2" tubing. Either it's 1-1/2" for the inside tubing or for the outside. Doesn't really matter.

It's not just for the grinder. It's also for future projects that require something that can be extendable.

 

[mmcmdl]

Look up trailer stock . I had a shi* load of stainless tubing for making tractor hitches . A member here came and got it all . ( Can't remember who ) Now I wish I had some of it here .

 

[Jake M]

I'm planning on making a belt grinder, similar to the one in this picture. I want to know what sizes these square tubings are where I can fit on into a larger tubing

I'm guessing that's a 2X belt, just because of the popularity.

That would make the nesting tubes 2 inch and 1.5 inch.

If you look close, you'll see there's a significant gap. I'm guessing (and proprotionally it looks about right) that they went with a 3/16 wall, leaving (about) an eighth inch clearance.

This stuff is "sized" by it's outside dimension and wall thickness. So the outside dimension minus two wall thicknesses is the inside dimension.

It is NOT precision material. So 2 inch and 1.5 inch with a quarter inch wall will NOT slide together, even if you had zero weld seam. Gotta have some slop there.

Short of specialized (and expensive) material (which IS available), there will be a weld seam. USUALLY, a 3/16 wall on those two sizes slide together pretty OK, but they can interfere slightly. In shorter lengths like that, it is (usually) pretty easy to deal with as it's not much interference.

I "think" I can see it in that picture, although it's been "dressed" but also note that if you're clamping with a knob such as that for positioning, the weld seam on the outside tube, that's on the same side as the knob, pushing the inside tube AWAY from the seam. Leaving it in the other three orientations will be annoying at best, and probably mess with the alignment it were oriented opposite of the screw knob.

 

[Charles scozzari]

This may help somewhat, I hope. When I have to insert lets say a 2"I.D square into a 2 3/8" O.D. square the continuous welded seam interference will not allow it to slide in. In what I was doing the lengths were 18" so attempting to file the inner weld seam of the 2 3/8" tube I ran a groove the full length of the 2" O.D. tube to allow the weld seam of the 2 3/8" tube to clear the weld using a 1/8" end mill. Worked nicely for me. Square corners SO FAR haven't been a problem.

 

[Flyinfool]

There are a bunch of YouTube vids with ways to remove the inside weld flash.
If you need a fairly good fit Get the nominal sizes. ie 2" x 1/4 wall and then a 1.5" x 1/4 wall for the inside.
Remove the weld flash on the outer tube. Or grove the inner tube.
Machine 2 sides of the inner tube to get the fit you want.