box section bending

[sparky_col]

does anyone know any measurements for cutting and welding box to create a gentle curve in it? i have done similar things with cable tray years ago to create round 90degree bends but i cant remember what the measurmenst for the cuts was i can only remember that you did cuts at a certain distance appart and the cut 6mm either side of the cut down to the base of the cut creating a v shape, this then formed a nice even curve when folded up. im not looking to make a 90 degree bend, something a bit less.
thanks for any help.

 

[outofthefire]

I dont know how to work it out matematically, I'd cut it every 1" with a 3mm cutting disk bend it and weld it then repeat if its not a tight enough curve.

 

[astro_al]

Just pull it round a former?

Al.

 

[Wedg1e]

I dont know how to work it out matematically, I'd cut it every 1" with a 3mm cutting disk bend it and weld it then repeat if its not a tight enough curve.

I found that even a hacksaw blade's width cut gives you a surprising amount of angular displacemert... well on 25mm box anyway.

 

[BrokenBiker]

ive seen fabby's do it by making a mid point cut, and a slight bend, then cuts either side of that, and keep working their way outwards from the first cut, and then if its still not right, make the cuts wider until it is

 

[gordon stephenson]

What size box section are you planning on bending?

 

[hotrodder]

Just pull it round a former?

Al.

For gentle curves, this^^. Springback is something that needs to be accounted for, you can either tweak things until it looks right/fits a template or if wanting several pieces of the same shape use larger formers that account for springback. The later is discussed in more depth here along with some springback data from the author... http://metalgeek.com/archives/2005/05/01/000047.php

If cutting and welding notches then it's kinda the same deal as with segmented/lobster back bends. There are programs and calculators about for those like this one from TyHarness

 

[andytm]

that looks like a great bit of software would save me lots of time getting out the cardboard and scissors

 

[sparky_col]

Thanks for all your replies, its 75 x 75 box that i want to bend, i have no access to formers or bending equipment so i will try the cut and shut method

 

[Hitch]

You wont be pulling that round by hand, even if you did have formers.

Just splay cut it. The more cuts you do, the smoother it is obviously.

 

[BrokenBiker]

There are programs and calculators about for those like this one from TyHarness

downloaded this and i have to say, its brilliant. and very accurate. easy to use and will do anything you want it to

 

[hotrodder]

Checkout the links section of the site if you haven't already... http://www.mig-welding.co.uk/forum/forumdisplay.php?f=58, should find a bunch of other shareware for similar things