Bending square section steel tube

[RickH]

Time for another project ... need to put a 90 degree bend in some 1.25" square section tube.
Not bought the section yet but guessing something like 16 gauge (0.064") or maybe I will need 14 gauge (0.08")
Obviously the bend radius will mean a reasonably gentle bend.

I have 2 questions if anybody has experience of such things.

# What is the minimum bend radius, I'll make sure I keep above this.

# Is this a practical bend to do at home ... or should I go to a fabricator and buy it 'bent'

If you are interested the project is:
http://www.eharder.com/Nova II/Trailer/Guide-on.html

(Not mine, just following somebody elses work.)

 

[ColJack]

you'll bend round tube much easier.. 25mm steel conduit would do you.. the rollers would roll round it easier too

 

[Trazor]

you'll bend round tube much easier.. 25mm steel conduit would do you.. the rollers would roll round it easier too

With the correct tools, It's much easier to bend square tube, as round tube has a greater radial strength.

For square tube you will need a specially shaped former to collapse the inner face uniformly.
You can see what happens to square tube when bent, in the pictures in your link.

With 1.25"sq. x 16 swg ERW, your centerline radius will be approx. 150 m/m

Find a local tube bender if you need smooth uniform bends, bending without the correct tools will crush the tube.
He will also tell you the radius he can bend.

 

[ColJack]

yes but a 25mm conduit bender will be much ore readily available than a 1.25" square section bende.. and as it's for putting plastic pipe on as "rollers" I thought that round tube might be a better option..

 

[Trazor]

yes but a 25mm conduit bender will be much ore readily available than a 1.25" square section bende.. and as it's for putting plastic pipe on as "rollers" I thought that round tube might be a better option..

Fair point, but looking further at the application, square tube for the bottom half, lends itself better for the final fitting onto the trailer.

Giving it further thought, I would not bend the tube, but I would weld a 90 degree joint instead and strengthen the corner with a welded gusset plate.
Much stronger than a bent tube.