what metal pipe/tube to use?

Hi, I'd like to weld together a stand for a halogen light for my workshop. (I find the stands that come with most halogen lights way
too fragile, plastic parts, etc, yuck.) I don't care about weight, I fact I would appreciate a stand that doesn't get knocked over so easily.
My problem is finding a pipe or tube in mild steel that will "nest" in the next biggest size with say a 1/16" of play --so that my stand will have a telescoping column for height adjustment. I'm looking for a max outer dia of about @ 1.5".
I looked into EMT (electrical metallic tubing) aka thin-wall conduit but it is too thin and has too much play between the outer wall of the inner tube and the inner wall of outer tube.
I looked at black schedule 40 pipe because it's relatively cheap but it doesn't nest, very close, but it doesn't nest --at least not the stuff I found at Lowes. (No I don't have a lathe.)
I thought of trying thick-wall conduit. One-inch RMC (or RSC) will nest in a 1-1/4" (according to a table I found). But it's so expensive! --smooth bore and galvanization in and out.
What would you metal fabbers use? My ideal wall thickness would be around 3/32".
--zeb
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snipped-for-privacy@hotmail.com wrote:

Telescoping tubing, if I were to do that. My halogen light stand is a little, um, simpler. I took an old BBQ propane bottle, flushed it, removed the valve, cut the top off right where the cylindrical part stops, and kept the bottom part for a little slack tank. The top part I just set down on the ground, where it acts like a solid little base with a 3/4" female NPT hole in it. I threaded in a piece of 3/4" pipe maybe 3 or 4 feet tall. Now I have a vertical pipe which is hard to tip over. Then I took a piece of 4x4 about 10" long and drilled a blind hole in it for a loose fit over the pipe. Now I have a rotating wooden support in midair, which is hard to tip over. Then I basically stapled on my little halogen light fixture.
Mine's adjustable in height. The light can be up on top of the pole, or down on the ground. That's *plenty* of adjustment. Those halogen shop lights tilt up and down, that provides all the remaining adjustment needed.
I think that light stand took me 10 minutes to make.
If you need some telescoping tubing, try onlinemetals.com or some other online metal source.
GWE
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Zeb, look for 1" and 3/4" ridgid conduit (or standard sch 40 pipe size). These will telescope perfectly if the welding flash is not excessive inside the 1" size. I have made many assemblies with this material. RichD
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Half inch water pipe and 1/2" round solid stock to slide inside. Go to any auto repair place that does brakes and get the largest scrap disk rotor you can find for a base. The four I got were free, but you might have to pay a buck or two.
Pete Stanaitis --------------------
snipped-for-privacy@hotmail.com wrote:

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On Sat, 07 Oct 2006 10:54:52 -0500, with neither quill nor qualm,

Wouldn't that make the lamp rod top-heavy as Hell, Pete?
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Would the lamp rod be too heavy? I don't think so. I have used several of these as adjustable stands. I use brake rotors from trucks. I just went out and weighed one that is 32 pounds and is about 18 inches in diameter. If you are asking about the weight of the 1/2" rod,: 6 feet of it is about 14.4 cu. in. 14.4 X 0.283 = about 4 pounds. I don't see that as an issue unless the lights weigh 25 or 30 pounds and are 8 or 10 feet off the ground. BTW, I use about 3 1/2 feet of 1/2" water pipe with a 1/4-20 threaded hole in the side and a threaded eye from the hardware store to hold the rod at the desired angle.
If I am missing something in your question, let me know.
Pete Stanaitis ----------------
Larry Jaques wrote:

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Pipe and rigid conduit use the same speicifications, none of the sizes telesope together. Thinwall conduit (EMT) slides together but way too much slop. Ther is an intermediate grade of electrical conduit called IMC that works fairly well. Not cheap but cheaper than special order materials. Check out this table, you will need to subtract 2x wall thickness for the inside daimeter. .030" to .050" difference gives a nice slide clearance for your use. http://www.vogeltool.com/conduit.html
3/4" conduit is not too bad a fit into 1" pipe or 1" conduit.
snipped-for-privacy@hotmail.com wrote:

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I can't remember if the OP has a lathe or not. If he has, it's easy... Make a spacer ring to fit on the (undersized) inner tube and a gland to fit on top of the outer tube. With a bit of thought and an O ring, the gland at the top of the outer tube can be used as a friction clamp to stop the thing from un-extending itself.
Mark Rand RTFM
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wrote:

I used 1" and 3/4" square tubing. I think it's about .070" wall. That makes a loose fit, which is perfectly fine for the task. Weld the nut on the seam side.
http://www.citlink.net/~wmbjk/images/lightstand.jpg . Ignore the 1" horizontal piece, it's part of the door in the background. Make the base wider and heavier if you want it more stable. I used three bulbs - a 12W compact florescent flood for modest light that doesn't get hot, an incandescent 75W flood for medium light, and a 150W halogen. I can point them 3 different directions if needed. ;-)
Wayne
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