Straightening small copper tube

What's the best way to straighten small copper tube from a coil? At the moment I cut off a short length, anneal it and then roll it between 2 bits of MDF. It seems to work but I am sure there must be a better way to do it. Look forward to hearing better ideas.

Bob

One method I read about and have tried was to cut off a length longer than needed. Clamp one end in the bench vice and clamp the other end in a pair of mole grips at right angles to the tube and then give them a whack with a hammer.I did this without annealing so the tube wasn't stretched

What do you call small diameter tube ? When I operated a spark erosion machine we often used tube of 1mm or less to put small holes in. This was gripped in a collet chuck ready to fit on the spark machine, we would then put the collet chuck in the lathe three jaw and spin at 800 or more revs. When spinning lightly grip the tube with finger and thumb close to where being held and run your hand away from the chuck towards the tailstock. Sounds dangerous and scary but works and tube comes out straight after a couple of goes.

I would say that's probably the best way to do it Bob, it works well for me.

Pyro MICC cable uses a roller box to straighten it after decoiling, thin sheet steel is straightened with a set of rollers after decoiling but the machine must be set up to run continuously or you will get roller marks that will be visible in the finished panels.

Mike

Thanks for those ideas. I wasn't thinking when I posted originally - by small I meant anything from ⅛" to ¼". I'm going to give the "Mole and hammer method a go but Chris sounds a braver man than me! ......... or am I just being a wimp? Bob

Another vote for Mike's suggestion....

I've installed a lot of Pyro in my time, there is a proper tool for straightening Pyro...

I've even visited the Pyro works when it was at Hebburn while serving my apprenticeship...(seems so long ago now..)

We used to cut off a 10 foot length, attach one end to a beam and put a large weight on the other end. Leave overnight and in the morning it would be dead straight.

Good visit the BICC wonder how many apprentices did it, back to straitening depending on the length I roll mine

between two flat pieces of wood.

H

I think a 1mm pipe might do less damage than a 1/4" one...

My method for straightening small tube was brought about by necessity. You just can not use a DTI on tube sub 1mm diameter. Once on the spark machine the final check to see if it was straight was done using the machines audio facility, IE electrical contact and zero the read out then bring the quill down and check again.