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Old 10-30-2008, 05:12 PM
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Cavalry Cavalry is offline
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Default Building a press brake

I want a press brake for my 20 ton press, and found this one. http://www.northerntool.com/webapp/w...70_21896_21896 I dont see $300 worth of steel there so why not make one?

My first concern is heat treating. I am going to venture to say this is not heat treated as from the reviews one person claimed to heat treat it. Is it necessary to HT it or more so for frequent use? I have case hardened small parts before but nothing this big. I dont have a forge but have O/A. I would need some insight on temp to bring it to and how to cool.

What angle to make die set? I want to bend to 90* so I would assume to compensate for springback the blade should be a little sharper than 90*. How much is needed...85*?
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Old 10-30-2008, 06:32 PM
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Quote:
Originally Posted by Cavalry View Post

...

What angle to make die set? I want to bend to 90* so I would assume to compensate for springback the blade should be a little sharper than 90*. How much is needed...85*?
This depends on what type of material you are bending, if you give me an idea of what you are wanting to bend, I can sketch you a couple of dies in AutoCad that you could make from readily available materials.
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Old 10-30-2008, 06:34 PM
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I want it be pretty multipurpose. I can see a lot of 1/8 and 1/4" steel use and I do have a job in mind that will require 1/2x2 (but not to 90*)
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Old 10-30-2008, 07:19 PM
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Cav, here is one that I made some years ago. The first one that I made I gave to a friend and this second one I never really completed the male die. The male die should be as long as the angles are and have a socket that would fit the ram and be welded to the square bar. That there be a piece of plate that would reinforce the square bar out to each end of the square bar. The socket would be welded to the plate some what like the small die that is in the picture.

With this male die you just place the square bar where you need the bend and push on the round part.

My explanation is not very good and I hope you can make out what I am trying to say.
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Old 10-30-2008, 10:31 PM
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Cav, check out the drawing below, should be about what you are looking for, It is important that you use a bottom die with an opening of at least 8 times the material thickness. That is a pretty standard "rule of thumb" as with all rules, they are made to be broken, so other configurations can be used.
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Old 10-30-2008, 11:07 PM
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Cav.. I have a couple sets of dies I made long ago ...just like Charlies. For my top die I used a piece of that ol' "T" from a very old bumper jack. It's very tough stuff. I had to sharpen it a bit with a grinder tho.
The bottom dies...one has a right angle guide on it.. That's the one use the most.
I have no idea how many things I've bent with these. Prolly thousands. I had an order awhile back for 500 1/4" thick X 3"W 90* brackets. Have done a lot of other 2 and 3hundred piece orders. All done with the homemade dies.
Russ
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Old 11-01-2008, 10:47 PM
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Default Add some stops

I have used a machine shop built version of the H-frame "press brake attachment". They had built several over the years, including one with adjustable stop rods that used standard press brake tooling.

The other ones just had a flat spot one each end where you could a custom thickness spacer block. We simply kept reducing the thickness of the block till we got the angle we wanted. Then we stamped the gage, job# and angle produced on them for next time.

We had a nice 4' wide 50 ton dake with power hydraulics. Someone had rigged it with a adjustable pressure "auto-return" logsplitter valve. So it was just load and shoot.

They made a lot of cash doing simple jobs on this simple machine with such simple tooling, that I wanted to build my own, and create a part time garage shop biz. But I went to college instead!

This guy puts a lot of thought into his designs, (So we don't have too!) http://www.davepropst.com/Article/Art6/Article6.htm mark
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