ring roller for tubes??

[johnakay]

I have some bending to do that cannot be done on a normal former.
radius is about 13" and it'll cost me a fortune to get one made up.
the grab rail that I'm about to make is about a 3rd of a radius.
the question is would it work if I made a ring roller of sort with out distorting the tube.tube size is 16mm x 1.5mm wall.any ideas that might help will be much appreciated. john

 

[Weldingartisan]

If it's a one off, you could try boring a slightly larger hole in a length of timber, say 4"x2".
Mark out the length of the bend on the tube, divide into equal parts approx 40mm and bend a few degrees on each mark by feeding the tube through the timber. Repeat until the desired radius/angle is achieved. W/A.

 

[Blackjack]

16mm x 1.5mm on a 13" radius?

With a radius of around 20 times the tubes diameter, I'd try cutting out a piece of MDF and pulling the tube round that.

Allowing for springback, rough guess, stab in the dark, cut the former on a 12" radius.

Screw the former to a base board.

Screw a stop to the base board.

Stuff the tube in, pull on the end.

 

[dopplershift]

You can always pack the tube with sand if your worried about a bit of distortion.

I'd always thought you had to weld caps onto the tube to hold the sand in under the pressure of the bend, but there was a video somewhere of a guy who just used heaps of gaffa to keep the sand in after packing it down. That seemed to work fine.

 

[hotrodder]

I've bent tubing similar to that around an old car wheel before- a couple of different radii possible for a given wheel size.

 

[johnakay]

16mm x 1.5mm on a 13" radius?

With a radius of around 20 times the tubes diameter, I'd try cutting out a piece of MDF and pulling the tube round that.

Allowing for springback, rough guess, stab in the dark, cut the former on a 12" radius.

Screw the former to a base board.

Screw a stop to the base board.

Stuff the tube in, pull on the end.

thats what I had in mind,will make my own ringroller and see how that goes if it doesn't work then I'll try the above. not making one but quite a few it all depends on demand.

 

[Blackjack]

thats what I had in mind,will make my own ringroller and see how that goes if it doesn't work then I'll try the above. not making one but quite a few it all depends on demand.

If you're making quite a few, then I'd do it the way I described.

It's quicker, and there's no set up involved.

That's not to say don't make the ring roller, just that having done a fair bit of production work I'd do it by making a dedicated former.

Wood or MDF is fine for a few tens, but if you're thinking hundreds, A piece of scrap plate with some strap welded to it on edge won't wear.

Then weld a length of box on the other side of the plate so it can be clamped in the vice.

I've got probably half a dozen different ones under my bench.

 

[Blackjack]

I've bent tubing similar to that around an old car wheel before- a couple of different radii possible for a given wheel size.

For smaller radii, old brake discs are handy too. Most garages that do MOT work chuck out several sets a month...