Improved DIY Tensahedron Stand:

[WhollyHamaca]

Hi folks, Just an update and an afterthought re. my low-tech, no-time-to-ship "quick-fix" for a snug fit of 3/4" poles into 1" emt sleeves: My nephew called to say the JB-Welded flashing spacers held up fine last night, and he's just set up again for tonight. Close assembly fit, no wiggles, and came apart easily to pack up again. The flashing spacers are still firmly glued onto the pole ends. He's pleased that I could make his stand portable on a few hours notice with materials I had on hand, and he's bestowed extra brownie points on his favourite auntie. Good enough given the time crunch, but not entirely to my satisfaction because the flashing was a pain to cut and roll tightly around the poles to get a good fit while also messing with the glue.

So (too late) I've thought of another way. It's not nearly as slick as the sleeve tubing suggested above, but I think it will work if you just don't have time or cash to order the tubing before your next trip out, or if your pole joints are too loose for whatever reason. And it may be stronger than the Al tubing sleeves?

I've repaired loose antique wood furniture and woodwind instrument joints by wrapping the tenons with thin linen cord and hard wax. Clearly that won't work well for anything exposed to weather or rough use, BUT it occurs to me now that I could have filled the gaps in the emt joints more quickly and easily with WIRE epoxied in place, wrapping the wire in a smooth single layer around the 3/4" pole end for 4" starting very near the end (so it will fit halfway into an 8" long sleeve of 1" emt) and leaving unwrapped spaces for the rivet holes. It might suffice to wrap the wire with some space between the coils (so it looks like a stretched spring wrapped around the emt), and epoxy the wire in place. The gauge of wire needed for snug joints probably is trial and error due to the tolerance range in the actual (not just nominal) ID and OD for the readily available big-box pipe & conduit. I think I'd rather use bare wire instead of insulated. Either way it will get covered with epoxy. I'll let you know how it goes when I get a chance to try it.

[jeff-oh]

Not bad. If you drilled a little hole at the start and stop point may not even have to glue down. just feed through and bend snug.

[WhollyHamaca]

Not bad. If you drilled a little hole at the start and stop point may not even have to glue down. just feed through and bend snug.

Good suggestion, thanks! If the wire is stiff enough to hold a bend in the holes, it would make winding it on easier. If needed also a spot of glue to secure the wire in the start and end holes. I was thinking the epoxy would also hold the wraps firmly in place with the friction of repeated assembly, but it may not make a difference as long as they're tightly wound and the ends don't come loose. I think this would work in a pinch with readily available materials, but if I'd had time to order before my nephew's sudden trip, those Al tubing sleeves would be a much simpler way to achieve tight-fitting joints.

[ylnfrt]

In answer to my own question above, I found some tables listing EMT specs, here is one: https://www.sizes.com/materials/conduit_EMT.htm

This one says 1" EMT has a wall thickness of .057 and 1.163 actual OD, and ID 1.049. (that math does not quite work out for me. 1.163 OD minus wall thickness .057 should equal ID of 1.106, no? ) and 3/4 OD of .922. But going by their spec of 1" ID of 1.049 minis 3/4" OD .922= .127 dif, so I guess that is the loose fit. But, the 1" EMT wall thickness is actually thicker than what was used in this project.

This table lists similar specs, but does not list ID:
https://steeltubeinstitute.org/steel...ic-tubing-emt/

Don't you need to deduct the wall thickness- twice- from the OD to get ID? 1.163 OD- .057 x 2 WT = 1.o49 ID . math works for me

[BillyBob58]

Hi folks, Just an update and an afterthought re. my low-tech, no-time-to-ship "quick-fix" for a snug fit of 3/4" poles into 1" emt sleeves: My nephew called to say the JB-Welded flashing spacers held up fine last night, and he's just set up again for tonight. Close assembly fit, no wiggles, and came apart easily to pack up again. The flashing spacers are still firmly glued onto the pole ends. He's pleased that I could make his stand portable on a few hours notice with materials I had on hand, and he's bestowed extra brownie points on his favourite auntie. Good enough given the time crunch, but not entirely to my satisfaction because the flashing was a pain to cut and roll tightly around the poles to get a good fit while also messing with the glue.

So (too late) I've thought of another way. It's not nearly as slick as the sleeve tubing suggested above, but I think it will work if you just don't have time or cash to order the tubing before your next trip out, or if your pole joints are too loose for whatever reason. And it may be stronger than the Al tubing sleeves?

I've repaired loose antique wood furniture and woodwind instrument joints by wrapping the tenons with thin linen cord and hard wax. Clearly that won't work well for anything exposed to weather or rough use, BUT it occurs to me now that I could have filled the gaps in the emt joints more quickly and easily with WIRE epoxied in place, wrapping the wire in a smooth single layer around the 3/4" pole end for 4" starting very near the end (so it will fit halfway into an 8" long sleeve of 1" emt) and leaving unwrapped spaces for the rivet holes. It might suffice to wrap the wire with some space between the coils (so it looks like a stretched spring wrapped around the emt), and epoxy the wire in place. The gauge of wire needed for snug joints probably is trial and error due to the tolerance range in the actual (not just nominal) ID and OD for the readily available big-box pipe & conduit. I think I'd rather use bare wire instead of insulated. Either way it will get covered with epoxy. I'll let you know how it goes when I get a chance to try it.

Not bad. If you drilled a little hole at the start and stop point may not even have to glue down. just feed through and bend snug.

Good suggestion, thanks! If the wire is stiff enough to hold a bend in the holes, it would make winding it on easier. If needed also a spot of glue to secure the wire in the start and end holes. I was thinking the epoxy would also hold the wraps firmly in place with the friction of repeated assembly, but it may not make a difference as long as they're tightly wound and the ends don't come loose. I think this would work in a pinch with readily available materials, but if I'd had time to order before my nephew's sudden trip, those Al tubing sleeves would be a much simpler way to achieve tight-fitting joints.

Don't you need to deduct the wall thickness- twice- from the OD to get ID? 1.163 OD- .057 x 2 WT = 1.o49 ID . math works for me

Yes, that certainly makes sense, thanks for catching that!

I'm wondering about some dirt cheap(from HF) mechanics wire for wrapping the 3/4"? It's pretty thin. Too thin? 20AWG diameter, gauge I guess, whatever that is for diameter.

[WhollyHamaca]

I'm wondering about some dirt cheap(from HF) mechanics wire for wrapping the 3/4"? It's pretty thin. Too thin? 20AWG diameter, gauge I guess, whatever that is for diameter.

Thanks for the suggestion & link! According to this 20AWG in electrical steel is 0.032 diameter. The nominal difference between 3/4" OD (0.922) and 1" ID (1.049) emt is 0.127 (this table), so diameter about half of that should fill the gap: about 0.0625 (1/16"). That's just a touch smaller than AWG 14, so I'll try AWG 15 or 16 plus epoxy to secure the wire in place and to fill any remaining gap. Home Depot has this 16 gauge galvanized steel wire that should work and is certainly cheap enough to try. I'll try to take a jaunt over there tomorrow with some short bits of emt and see what they have that fits. I also have a couple other easier & maybe better alternatives in mind.

I really appreciate all the helpful suggestions I've received about my little project! Now that we have confirmation that the aluminum tubing sleeves are a very close fit for emt joints, my continued interest in this exercise probably seems to some minds a waste of effort. That may be so, but I'm pursuing other options anyway because the bug is still in my head. It was clear to me how much we've come to rely on internet orders while I was struggling to kluge my nephew's stand to be portable with just a few hours notice and only big-box stores for miles around. It was a challenge I enjoyed, and imperfect as my quick-fix method was it's still holding up quite well. I'd like to find a way I could have done better with common, locally available materials and simple tools, so that anybody else could. In any case, there may be a few diy'ers who don't want to spring for aluminum tubing that =to me= doesn't seem as robust as the poles it joins, yet I admire the 'discovery' of it as the tightest and easiest fit we've seen so far. I'm hoping one or another of my little experiments can lead to a sturdy, low-cost, low-effort, off-the-shelf alternative. Clearly no genius here, just another old fool playing around with simple ideas & materials in case of an occasional useful outcome. /end of dither/

[jeff-oh]

Free AL tubing for anyone who want it...

This morning I saw on the side of the road, I-275 in Cincinnati, a Weber Grill. The Legs on the grill are the right size needed for this project. Free to the first person to stop by and pick it up... But hurry I'm sure it won't be there for long.

It was still there on the way home from work. The though did go through my mind to stop and toss it in the trunk.

[Theguywitheyebrows]

Free AL tubing for anyone who want it...

This morning I saw on the side of the road, I-275 in Cincinnati, a Weber Grill. The Legs on the grill are the right size needed for this project. Free to the first person to stop by and pick it up... But hurry I'm sure it won't be there for long.

It was still there on the way home from work. The though did go through my mind to stop and toss it in the trunk.

Oh really? I think i know where one of them dudes is layin dead in a field...hmm wish me luck lol

[jeff-oh]

The Dirtier connection tube at the top is actually from a Weber grill. May have to sand the inside a little to remove the weld burrs. I did this by working one of the scrap pieces of EMT in it.

Attachment 176789

[P-Dub]

I'd be concerned about steel and aluminum in contact with one another, especially outdoors b/c of electrolysis (besides the potential strength differential)