Want to make: bender 48"x7ga

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I've searched the board and the net but haven't come across any good plans for making a simple bender that can handle 7ga (3/16") x 48". Industrial benders in that size are several thousand dollars, and no doubt have more features/accuracy than I need. I just need to fold a 90 degree bend in length of about 42". The ideal design would have a simple clamp down on the work piece and an arm to make the fold. I know 7ga is heavy so I reach out to the knowledge of the board for guidance.
Reply:Large hydraulic shop press and a wide press brake.http://www.northerntool.com/webapp/w...6970_7902_7902I know their 20 ton unit will only bend 3/16" steel, 10" wide. I'm guessing you are going to need an 80 ton press to do 3/16" steel, 42" wide. A simple fold type bender ain't going to cut it.(Someone posted up the math here somewhere as to how many tons it takes to bend what, but I can't find it right now. I'm operating on the theory if you need 20 ton to bend 10" you will need 4X the press to bend 4X the width.).No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:If you want cheap, hire it done.  The guy I have do bending for me on longer pieces gets about $20 a bend.  Probably a bit steep for 2 minutes of work, but he has the equipment and I don't.My name's not Jim....
Reply:there aint no cheap way to do this.I have a 48" x 12 ga hand brake- it weighs 2000lbs, and is only that light because its well engineered, with lots of parts cast or machined to be no heavier than they have to be.12 gage is about as thick as hand brakes were ever made- beyond that, in thickness, its just too hard to do by hand, you need either mechanical or hydraulic machines.to bend metal, the force needed increases with the square of the added thickness- this means you need 4 times the force, and mass and stiffness, to bend twice the thickness.So a nice commercial brake to bend 7 gage mild steel would probably weigh around 4000lbs, assuming it was a good design that used minimal amounts of metal in carefully engineered ways.To kludge one together from scrap, figure more weight.Here is a page with power leaf brakes- a 3/16" brake shown, which is 96" long, weighs 6500lbs and is probably well over ten grand.http://www.americanmachinetools.com/press_brake.htmJust paying scrap prices for steel, you get up to a couple grand pretty quick and thats with no machining or welding thrown in.Its true, a press brake will do the job- or a hydraulic brake with press brake dies. But to get a nice even bend across 4' is a lot harder than bending 20"- you need more mass for alingnment and even pressure. Here is a link to a tonnage chart-http://www.americanmachinetools.com/pressure_table.htmas you can see, an absolute minimum of 11 tons per foot- or 50 tons- and thats with everything built professionally, to maximum tolerances and perfection. A homebuilt 7 gage press would probably be happier with 80 tons or so.The best bang for the buck, the cheapest way to do this, if you want to buy your own machine, would be to buy a very old, used mechanical press brake. OSHA hates mechanical brakes, as they are pretty dangerous, so they are seldom used in industry anymore- certainly, no real factory has been buying em for 20 or 30 years. But there are lots of used ones in the rust belt, often for less than scrap prices- but they are big and heavy- again, for the tonnage you need, figure at least 5000lbs of machine.Look here for some sample deals- obviously, cheaper if you dont buy from a dealer, but instead, an auction or a closing plant.http://www.machinetools.com/us/machi...ish%3Aa&page=2Something like this would do it-http://www.machinetools.com/us/machines/view/44273
Reply:As was already stated, hire it out.  The time and money you'd spend to do your one bend would far outweigh the jobber's rate for the work.
Reply:You can use an abrasive blade in a circular saw, or a cold saw.  Set up a fence, cut most of the way through, bend along the cut and the weld.  You will pobably need to bevel the cut for clearance and a proper weld, but it should work fine.  Another Idea would be to use a piece of angle welded to the flat.Rene