Advice on straightening tubing sought

Once metal has stretched, that’s it.

Nope if your careful you can heat shrink it..
Here is a pic of our rollers..Same principle..

use three rollers

You have not given much information on what kind of tube and what diameter and wall thickness.

Usually you can use three rollers that look like pulleys. Two are on the same plane and then another is above that plane and between the other two. One of them is adjustable versus the other two that are fixed. You roll the tube through and it will straighten right out if the adjustment of the adjustable pulley is correct.

This technique is used to make rings for radial engine motor mounts…..

Attached is a photo of a very small one that is used to straigten music wire that is coiled.

You should get the idea…… It is merely a matter of robustness.

That one shouldn’t be too difficult! Needs to be strong though….

Tony,

Joint E cross support for top seat mounts 😀

Ant.

If its Hurricane….good luck!!!! (Good luck anyway). Sand would be best as may stop it crimping/collasping. Some Hurri tubes can be brittle, some soft…..just take your time….and watch your thumbs!!

If you are willing to heat it then it’s easier. Just take it easy and don’t try to take too much of the bend away in one hit. Consider annealling the steel (heat to cherry red and allow to cool naturally) to prevent work hardening.

Ant,

Take care with that heat, you could make the metal brittle. Note item #8. The ‘ball method’ quoted above was used on much larger diameter coolant pipes, not the structural steel tubes you are attempting to straighten.
Best of luck.

OK then the avenue I would explore is to use a pipe bending spring of the exact diameter, low heat if it is aluminium, and if possible, a “template” to ensure that you have the correct alignment. Remember that aluminium has a grain. Please let us know if you succeed.

Yes of course you can get a replica made of most aircraft parts these days just nice to save an original bit though, it may be that it is NOT possible, but you have to explore every avenue and get as much advice as possible, especially if you do not have an engineering background, like me! Thats what the forum is for, amongst other things, and I am always very grateful for any advice from any member, so thanks again.

Ant.;)

Can you not get a replica made mate? I have never really been able to straighten bent tubing. Once metal has stretched, that’s it.

It would not be easy, of course ! But having seen what others have done I am often amazed at the results. The other option is to cut off the ends which are straight and have the connecting holes and weld in a new middle section, I will have a ponder for a while!

Thanks for the advice.:)

I think it’s do-able but difficult and would require skill to get a good result. I think the flypress and blow torch (oxyacetylene if you have access) is your best bet. I managed to straighten a badly bent aluminium tube for my Whitley front turret. I was told not to bother as it would crack. Well, it didn’t and it turned out very nicely in the end. If you need access to a fly press let me know.

I suspect you are on a hiding to nothing with this

Richard

You didn’t say what type of tubing it is, if it is from an A/C it is probably high tensile and quite thin, that being the case you will need to “cherry ” the metal to bend without cracking; the introduction of sand may help but will dissipate the heat, and you will need a big flame!

Depends on the diameter. Packing with sand is the best method if it’s larger, but you need to pack it in hard and seal both ends (probably best to seal one end first before you add the sand).

Get it roughly straight with vee blocks and fly-press or hydraulic press – the sand will prevent kinking or flattening. Bend it slightly past straight and allow it to spring back. Repeat lots.

If it’s quite a big diameter, then heat will be required, but with a press and blocks you can probably do up to 25 – 30 mm dia easily.

How straight do you want it?

Thanks,

Pipe bending springs are availible in 15 & 22mm, this is slightly bigger.

Could use kiln dried sand to pack tube.

Anyway will have a go.

Ant.

Our coppersmith at the ‘top gear test track’ had a nickname something like ”ball on a stick” so i guess the spherical method might just work LOL

You’d need a lot of balls to do that “OY”

Unless you can find a spring exactly the right diameter I would have thought sand would be best. It would need to be totally dry though – one of the few things I remember from college is that the volume of dry sand increases dramatically with the introduction of even a slight amount of moisture.

Roger Smith

Sounds a bit like the technique used on large bore lead pipe.
Using wooden bobbins

A chap in Canada, used steel balls attached to a cable, which he then pulled through the tubes to straighten them, he used progressively larger balls, finishing with ones that were the same diameter as the ID of the tubes he was straightening “also worked for removing kinks in the tubes as well”.

Bob T.