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!

On Tue, 25 Dec 2007 12:40:10 -0800, rgoldner wrote:

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!

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.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:
On Tue, 25 Dec 2007 12:40:10 -0800, rgoldner wrote:

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!

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.


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.

--
Steve W.
Near Cooperstown, New York

Life is not like a box of chocolates
it's more like a jar of jalapenos-
what you do today could burn your ass tomorrow!

In article , "Steve W."
wrote:

Tim Wescott wrote:
On Tue, 25 Dec 2007 12:40:10 -0800, rgoldner wrote:

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!

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.


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.

IIRC, aluminum bends best cold - dry ice cold

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

"rgoldner" wrote in message
...
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.

On Tue, 25 Dec 2007 19:58:28 -0500, "Chas Hurst"
wrote:


"rgoldner" wrote in message
...
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.

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.

On Dec 25, 1:40*pm, rgoldner wrote:
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!

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.

rgoldner wrote in news:8242e9d1-81d0-4257-8834-
:

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!

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

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
http://www.harborfreight.com/cpi/cta...emnumber=44094
work 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:
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!