Bending 1" X 1/8" aluminum bar

I have to put 35=B0 bends in 1" X 1/8" aluminum. I tried a vice and
hammering the end of the bar that sticks out about 1". This looked
real bad and if I bent the aluminum too much and tried to straiten it
a little it broke. Obviously, I don't have a metal brake. Is there a
better way to do this? I have to make eight bends. I do have a CNC
mill and a lathe as well as tooling and other assorted equipment.
Thanks!
Reply to
rgoldner
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You could make a little mandrel with a "V" groove anvil and matching punch, suitable rounded. Put the part on the anvil, and press the punch into the part with a hydraulic press. Plan on playing with springback a bit to get the angle just right.
The "trying to bend it back makes it break" worries me -- you may be able to control this with the radius on your punch, but you may just be using the wrong alloy of aluminum. I'd check on the alloy, to make sure it's kosher to bend it.
Reply to
Tim Wescott
If you have a GOOD vice make up a small set of jaws that will act like a brake. Just use a couple pieces of angle to form the jaws. HF used to carry something like this. Then mark the bend location and start bending. Make a bend template out of cardboard or sheet metal so you can pull the part and check it easily.
Reply to
Steve W.
IIRC, aluminum bends best cold - dry ice cold ;)
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Reply to
nick hull
I have to put 35° bends in 1" X 1/8" aluminum. I tried a vice and hammering the end of the bar that sticks out about 1". This looked real bad and if I bent the aluminum too much and tried to straiten it a little it broke. Obviously, I don't have a metal brake. Is there a better way to do this? I have to make eight bends. I do have a CNC mill and a lathe as well as tooling and other assorted equipment.
Thanks!
Clamp the strip between 2 pieces of wood in the vise. Use another piece of wood, struck with a hammer to fold over the strip. If you have problems with it cracking, the strip can be annealed using a propane or oxy-acetylene torch.
Reply to
Chas Hurst
With the equipment you have, why not mill a die set, and clamp that in the vise to do the bend? Female V and a male V.
Reply to
Brian Lawson
The suggestions that have been made already are pretty much in the ballpark, but the job you are describing really isn't very clear to me. Is the angle you are bending a.) 35 degrees from the straight-line bar condition, or b.) a 35 degree included angle for the bend? If I were doing a.), I would clamp the short end in the vise, and take advantage of added leverage of more material sticking out. Be aware also that you cannot create a zero-radius bend with sharp corners, even in the commonly available hardware store aluminum strip which I'm guessing you are using. Too tight a radius will lead to cracking and failure, either during your process or later while in use. I have often done this kind of thing using a standard V-block (90 degree V, some kind of stupid import grade is fine, obviously) as the bottom die, then cobble something together maybe with a mason's chisel or some other kind of at-hand tool to adapt for a top die, and a couple of hours later, you have a custom press brake. It's much easier to do if you have a hydraulic press, or even a good-sized arbor press. A 3-ton arbor press is a fine thing to have around for small sheet metal forming work, as long as you can set it up with your own home- made dies. A 12 or 20-ton hydraulic H-frame press gives you a little more ability and working room.
Reply to
matt
rgoldner wrote in news:8242e9d1-81d0-4257-8834- snipped-for-privacy@s12g2000prg.googlegroups.com:
Well, it really depends on what alloy you're trying to work, but I learned this trick from an old shopmaster I worked with years ago: You basically anneal and bend as you go. You heat the bend area slowly with a torch, checking it by pulling the torch away and rubbing the area with a small stick of wood. When the wood chars by touching the aluminum, you're at the right temperature. 35° is to far to go in one jump. Most alloys will work harden and fracture before that. Heat, test with the wood, bend 10° or so, repeat.
As far as the tools to do it, almost any wide-jaw pliers or vise-grips will work because when you hit that right temperature, the aluminum bends very easily.
- Bruce
Reply to
Bruce Spainhower
If the bar stock is the home store special from the rack (unknown alloy) AND your bend radius is at least 2x or 3x (1/4" to 3/8"), the bar will bend easily. For this, the only issue is repeatability of the bend and control of the bend radius. One of the bench benders
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great (you might need to do a new die, just use a piece of suitable cold rolled with a hole drilled through the center) You can do almost as good with a simple plate, some tapped holes, and some 1/2" hardened steel bolts as bend points.
If you are working with a stiff aluminum like 6061-T6 and a tight bend radius (less than 2x the thickness), you will be material limited and will need both good tooling and some what to anneal the material.
rgoldner wrote:
Reply to
RoyJ

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