Bendng 1/4" brass sheet?

J

joe_m

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I want to bend a couple pieces of brass sheet 1/4" thick, 3" wide and 12" long into an asymmetric shape - kind of a shallow arc about 8" long and a couple inches of semi-straight. If it was a lot thinner I could cut a mold out of two pieces of heavy oak timber, put the metal between them and squeeze. Can I do that with 1/4" thick brass 12x3? What if I used a press? How strong a press - could one of those HF deals do the trick? What if it was bronze instead of brass?
I know the "pros" have a shop full of rollers and brakes and stuff but I've got to make do with what I've got (nothing) or what I can get for very very very very cheap. (a small arbor press.)

thanks
Joe
 
You should be able to accomplish this with a press and the question would then be what size, but since you mentioned cheap, I'd make a form out of hardwood blocks and set it between a jack and the frame of my truck or tractor or whatever and put some load on it. You might have to get a bigger jack and/or a heavier vehicle but it will bend and since you say "shallow" arc it may be easier or more difficult than I think, the trick will be to make the form to just the right proportion to allow it to be the correct shape when it springs back.

Good Luck!
 
Joe,
I would be annealing the brass before I started, and staying away from bronze. Its more expensive and harder.
If you dont have a press at this stage then as x-ray said use a jack under something heavy.

Cheers Phil
 
HF stuff won't work. They specify 20 or 24 gauge sheet metal(or so). The brass will bend easier if you heat it up to barely red hot(don't MELT it!) and let it cool. It will be annealed then. Cold rolled brass is a LOT stronger than annealed.

I don't know what your exact shape is to be,but if you could borrow a garage's 50 ton press,and anneal the brass,I'm sure it will be fine.
 
It sounds like you'll be making a very gradual bend so all you'll need is a wooden form and an arbor press. If it's too hard to bend, just heat it to 650F or so and let it cool (or quench it in water if you like) to anneal. An easy way to judge the temp for brass or aluminum is to soot the part and then heat it just enough to burn the soot off.

The HF presses work fine since there aren't that many moving parts to fail, and the price is right. I've had one for a number of years and used it quite a bit.

Tom
 
Thanks for all the hints. Yes it's a gradual curve (the sides of a coffin-shaped smoothing plane) Looks like it won't be too hard to do.
 
I,ve made several curved side planes,and can't even recall how I bent them,and mine were steel!! If you use wooden forms and anneal the brass,be careful to not leave bandsaw cuts in the forms. They can,and will press into the brass,leaving you to have to get rid of them. If you have a wide opening vise,and anneal,and use hardwood forms,you could squeeze that small amount of curve in the vise. I probably just hammered my shapes with a soft face hammer over a pipe,checking the curves,so it's not that hard to do.

You might roll the annealed brass through a sheet metal roller,but NOT a HF roller.
 
I thought you annealed brass by heating and quenching it? That the way you anneal brass cartridges. Can someone clarify?
 
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