Bending 1/4" steel plate

[halltrail]

Ive been doing some research on H frame presses and I need some help confirming my thoughts. Id like to get a 40 ton H frame press and then make or buy a brake so that I can bend 1/4" steel plate to 90 degrees and/or two 45 degree bends. Something like this:



The 1/4" plate will be about 12.5" inches wide. From what I have read, It looks like you need 20 tons of pressure to bend 1/4" plate @12" wide. So the 40 ton model should be good. Im not sure if I can make the brake with angle iron or not...and Im not sure exactly you you safely attach the punch part to the press??? Any thoughts on the brake and if the h press is an ok tool to do what I want?

Here is a link to what Im doing:http://weldingweb.com/showthread.php?t=22752. Right now im just heating and bending.

Dave

[Fat Bastard]

That press should do you for a while. You can nest a bunch of angle together to come up with a bottom die. (the tighter you nest them the better)

For a top punch a section of flat bar (1/2") with a section of cold rolled round welded to it makes a great punch for large radius bends.

Good luck
TJ

[farmersamm]

Check out Northern Tool and Equipment. They have a website. They have 2 different sizes of brakes that can be added to a hydraulic press. And they're made in America.

[Donald Branscom]

This plan does not make any sense if i understand it correctly.

Why not just buy the angles, beams, etc., that you will need.


To bend 1/4 inch steel plate it will take some real POWER.
Go to any steel supplier or large fabrication place and watch a 1/4 inch plate being bent.

[Rojodiablo]

A press should do the trick, and you can bend up tabs and such. But bending 1/4" with a brake is going to be a lot like Donald described- 1/4" sheet is some very stubborn material, and you will need a LOT of power to bend it cleanly. We used to bend up to 1/4" sheet on a 12ft. brake. It was hydaulic, and had a flywheel that spun above it to drive the ram; that flywheel and arm looked like they came of an old steam powered locomotive. When we would hit it to 1/4" steel, you could feel it in the floor from 40 ft away. Pedal down, Wa-BOOM! I still remember that sound like it was yesterday.

[Sandy]

Yeh, I don't think the phrase "brake" matches what he wants to do here?? Just a simple punch and die bend huh? Don't know for sure how tight the bend needs to be. Looking at that skid plate in the other thread looks like the bend radius is kinda open yet.

[halltrail]

The bend in the pics were done with heating and bending by hand. It just turned out very round. The bend doesnt have to be a perfect 90 and it can have a large radius...but smaller than what I did by hand/heat. Based on some of the later opinions posted, is it fair to say than that the calculator on http://www.e-ci.com/loadcalc.php isnt really correct when using an h press and brake? If I did it correctly, using a 2 inch gap die, 1/4 steel plate, and 12" wide you need 15.3 tons.

[Brad Blazer]

The die gap is key. I've bent 1x1 solid on my 12 ton press with about a 6" gap. 1x1 solid is 5x as stiff as 1/4 x 12 (1/12 bh^3).




Your part dimension beyond the bend will limit the gap. The bend will concentrate at the nose - it will not be constant radius across the gap.

Use a round nose to prevent notching the inside of the bend and build a reinforced channel for the die. I made a sketch.

The northern tool press brakes feature a good setup for guiding the nose between the press and the plate.

[halltrail]

Brad, Thanks for the sketch. Im still looking for a good place/deal on a press.

[Brad Blazer]

This one is interesting considering the price of most of the 40 ton units out there:
http://www.harborfreight.com/cpi/cta...emnumber=96188

[aametalmaster]

Check out this one.
http://www.shopoutfitters.com/Univer...abricator.html
Another thing is the bottom die should have an opening 8 times the thickness of the metal to be bent...Bob

[halltrail]

All good stuff, thanks fella's. I was most interested in making sure that If I pick up one of these presses that it would do the job I was looking for...thanks for all the help.

[Mondo]

American Machine Tools web site offers a chart showing how much power you need per linear foot to make 90° bends in various thicknesses of steel along with the optimum die opening.

http://www.americanmachinetools.com/pressure_table.htm

-Mondo

[Brad Blazer]

Great link Mondo.

Noticed another HF press in their catalog. 35 ton air/hyd for $500.
http://www.harborfreightusa.com/usa/...o?itemid=95865
To order online have to "order from printed catalog" here http://www.harborfreight.com/ and enter 95865-1csh.

[farmersamm]

Originally Posted by Mondo

American Machine Tools web site offers a chart showing how much power you need per linear foot to make 90° bends in various thicknesses of steel along with the optimum die opening.

http://www.americanmachinetools.com/pressure_table.htm

-Mondo

That's a really good site. They also have excellent primers on operating machines. Lot of the stuff is directly from the "Navy Repairmans Manual", also available online. It's a good reference for manual machining.

[halltrail]

Just an update, I picked up this Dake 25 ton press off of craigslist for a killer deal. Im not sure if it works yet. But, I couldnt pass it up for the price. I got it and then had to go on travel. But here is a picture of the exact same model (model#6-325 or 6-225) on ebay. As soon as I get back, Ill take pics of the actual unit I got. I cant wait to try it out.

Any one know anything about these? The one I got was made in 1976 and dake said I can still get parts for it. I know I need 4 pins for the moveable table channels and it looks like the set screw that holds the removable ram nose is snapped off. The one in the picture doesnt look like it has the removable ram nose on it.

Hopefully 25 tons will be enough. According to the site that mondo provided, it should be plenty.

[Xtreme Fabrication]

I got the one that northern tool sells in my 25 ton press. It works just find for 90% of what little bends I need to do. Anything else and I take it to my buddy. I bend up 7 stake pockets for a trailer out of some 4" by 1/4" flat stock. Took a whopping 10 mins. Only bitch to the H press brake attachments is the pumping of the manual 25 ton jack. Your arm gets tired.