Im kinda new to the fabrication thing (only about 2 yrs )
my question is how do you make a bend in some flat bar to a u shape like at the end of this parthttp://www.tregtrailers.com.au/TregWeldonCoupling5.jpg
I wan to make upper control arm ends of the axle end on a Dana 30

there are lots of ways:-) (just the answer you are looking for right?)

Anyway low tech would be to either clamp the piece to a work table and beat on it with a big hammer till it goes into the shape you want. Next step would be to heat the material and then beat on it with hammer. Next would be to rig up something with a shop press and a brake to bend them. I would probably opt for the semi low tech of hammer, flame wrench and clamps. Oh and if you have a big ass vice you could maybe use that to clamp it in if that is clamped to something sturdy...



Stew

This works good:

http://www.harborfreight.com/cpi/photos/44000-44099/44094.gif

Harbor Freight - $50

Or heat and a vise/hammer

I usually just chuck it up in the vise and beat it into shape with a BFH. However, I would not do this for the application you are asking about as it will be nowhere near as strong as two seperate plates welded to the axle if I am right about what I think you want to do.

welding is never better then bending steel. The heat affects the steel and causes it to become weaker in the heat affected zone ( area next to the weld)

If you're using heat to bend it, then there isn't really much difference. And if you're bending it to the point of the steel pulling apart, then again...welding would be better.

I would personally bend it with me press brake, otherwise I would use the gas axe/vice/hammer method.

rectangular HSS (box tubing) - cut it in half and then cut to length....voila....oh...and I'd disagree with the fact that bending is always better than welding...

bk