Straightening Copper Tube

I'm thinking a 2x4, 8ft long with a groove ripped it's full length, 1/4" wide x 1/4" deep and a 1x4 strip of wood to cover the groove; You would feed the tubing through the square hole and with an electric drill, turn the tubing until it's straight. I don't know if it would work, but that's what I would try if I had that project. It's certainly cheap enough. Try not to bend the tubing excessively as it will work harden. You may have to heat the tubing to anneal it.

Good idea. I believe that soap would help as a lubricant and a drawing agent

Have had some luck using a chunk of stainless steel rod just smaller than the inside diameter of the tube with a gradual bevel on the end being pushed through. The hardest part is holding the copper tube while pushing the rod through.

Have seen a straightener that pushed the tube over a smaller rod and through a bigger tube at the same time. However never got to see it work.

Using .25 copper tubing I have always rolled out 20 ft. and stretched out by clamping to a table and stretching with a come a long. This does not affect the OD of the tube. Compression fittings and tube are within tolerances.

Stretching it as suggested is how we've done it for years,

PI

Why on earth would you want to reinvent the wheel here? if a commercial product exists it will almost certainly be, by definition cheaper/better than anything you can devise and implement yourself.

"Sometimes the satisfaction of a job well done without purchasing or using someone elses tools can greatly out weigh the extra cost and effort put into the job"

KWS 1985