U shape brackets

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davidb

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Anyone have an easy way to bend metal into a U shape? I have access to several brakes. Making the first 90 degree bend is easy but how do you make the second 90 degree bend? Seems there's interference between the brake and the piece.

I'm trying to bend .010 4130 strips (1.5 in. wide) into a U shape that has 4 in. verticals and a 1.5 in. base.
 

bmcj

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Sometimes you have to establish the bend lines as well as you can (as close as possible to the final shape) and then finish (squeeze) the bend from the outside to it's final shape.
 

PTAirco

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Whenever possible I design U-brackets to be cut from square tubing, but that only works if you can decide on the dimensions. If you're building from plans, you're stuck with whatever they call for. I never had much success with calculating bend allowances etc.; the simplest way is to bend one flange and then bend the other around a formblock of the correct size, allowing for springback.
 

davidb

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Thanks guys for the ideas. I was thinking about those methods and have used them with less than optimal success on other parts but was hoping there was a better option. Then...

I just talked to a buddy that has a brake that he referred to as a "pan" brake. I discribed what I was trying to do and he said that as long as the U bottom was at least 1 inch and the sides were shorter than 6 inches, his brake could make the bends without interference. I'll see in a few days (when I go to his shop) if it will do the job and report back.
 

wally

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If the corner radius is small, what I would do is make a wood block 1.5 wide and a little over 4 inches high. Just clamp the block with the 4130 centered on it in a big vice and tap the side down with a hammer. I sometimes use a plastic hammer for things like this because it doesn't leave as many "hammer marks". Turn it over and tap the other side. Sounds like a piece of 2x4 would do it.

Scraps of wood and plywood are very handy for making form blocks to bend aluminum and steel around and over. A big vice is also a must-have for any shop or garage! Buy a good ome and a big one. It will last longer than you.
Wally
 

davidb

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Thanks Wally. I've done just as you describe before except I don't have a plastic hammer. I just use a scrap piece of hardwood between the metal and the hammer. I'll find out Wednesday night if my buddy's pan brake will make the task easier.
 

davidb

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Well, the pan brake won't work for the 1 1/2 inch bottom--4 inches is about the minimum but I can start the second bend and finish it with a block and hammer as was suggested.
 

ahs437

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Nov 4, 2007
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EAA has a video their site... basically it involves bending two pieces, drill and use a bolt with spacer to hold spacing and alignment and then fitting the base together for a weld. It could come out well with a little extra effort and solves some of the obvious problems...
 
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