Coiled tube ummm "spring"...

[dustjunkie]

I am looking for a coiled tube that will act as a spring of sorts. force to expand/contract is not important, in fact less is better, but I need it to expand and contract many times rapidly without fatiguing and breaking. Does anyone know of such a thing? Ideally the tube would be .0625-.125 I.D., and the coil spring would be 3/4" O.D. or so.

Thanks in advance for any help!

Jake

 

[berkshire]

Bourdon Tube?
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[btrueblood]

Grab some annealled tubing and coil it. Or order it that way from a custom spring shop. We roll our own here, but it's a 10" diameter coil of 3/8 OD tube. Works just fine, but we limit the stroke to keep the stress well below the predicted fatigue life we want to achieve. I'd have to dig a bit to find my equations for a coiled tube spring, but you should be able to derive them if you have a copy of Wahl's book on coil springs.

You don't specify the type of tubing you want - McMaster Carr has plastic (nylon and other) tubing in 1.5" o.d. coils.