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Discussion Starter #1
A while back I built this brake:

http://pirate4x4.com/forum/showthread.php?t=548940&highlight=





Now, while it did serve it's intended purpose of bending 3/8" and 1/2" thick flat stock, however, there were some drawbacks. First was that it would only bend to about 85° depending on material. Second, it wasn't very accurate. What I mean by that is even if the "blade" was positioned on the bend line, the parts would end up with minor variations. So, something better was needed.
After looking at a bunch of threads on here and other boards, I decided on a smallish self contained unit. I will still keep the old one around for the parts over 1/4" thick. I found with the old one that a 12 ton bottle jack was capable of bending 3/8"x4" alright, but, was maxed out with 1/2"x3" , so a 12ton jack should be more than enough for the new one with a limit of 1/4" thick x 8" wide. After scrounging thru the scraps and drops in the shop, I had enough stock to get started.


material: cold rolled steel

• 1 piece 7/8”x6”x12” flat stock
• 1 piece ¾”x4”x12” flat stock
• 1 piece ¾”x4”x8” flat stock
• 1 piece 5/8”x 2 ¼”x8 ¼” flat stock
• 1 piece 1”x 2”x6” bar stock
• 1 piece ½”x3”x8” flat stock
• 1 piece 1 ½”x 1 ½”x8” square bar stock
• 2 pieces 1” dia.x 16 ½” round bar stock
• 4 pieces ½”x 1 ¼”x 2 ¼” flat stock
• 2 pieces 1 ½” o.d x ¼” wall d.o.m tube x 4”

Hardware:

• 2- compression springs 1” i.d x 4” long
• 4- 5/8”-11 x 2 ¼” s.h.c.s
• 3- ½”-13 x 1 ¼” s.h.c.s
• 3- ½”-13 x ½” s.h.c.s
• 4- 3/8”-16 x 2 ¼” s.h.c.s
• 6- 3/8”-16 x ¾” socket head set screw


Started by laying out the hole locations in the base, jack and top plates along with the top plate gusset.



 

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Next thing to do was to drill,counter bore and tap the appropriate holes.









With that done, I started on the "blade" holder. Layout and drill all the holes followed by milling the 1/2" wide x 3/4" deep slot. After the milling is done the holes for the mounting bolts and set screws are tapped.

 

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Next, I chucked up one of the two uprights in the lathe so each end could be drilled and tapped for the 5/8-11 bolts. After the uprights were done, two 4" long pieces of 1 1/2"o.d.x1/4" wall d.o.m tube were chucked in the lathe and bored out to 1.005" for a nice slip fit over the uprights. Sorry, no pics of this.

Back to the mill, the cheap p.o.s angle vise was set up to cut the 100° (50°per side) angle on the blade.





While still at the mill, I set up to machine the bottom die. This took way to damn long. I do wish there was a Bridgeport in place of the mill/drill, but it is better than not having one at all. Started out with a 3/4" end mill and progressed down to 1/4".

 

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When that was done, the vise was removed and two "v" blocks and some small flat spring stock were used to set up for the clean up passes. With my limited tooling, this part was rather interesting to figure how to do it.



 

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When the milling was complete, the vise was reinstalled and the 3 bolt holes were drilled and tapped.

With all the machine work done, it was time for some assembly. The two uprights get bolted to the base, then the springs and pieces of tubing are slid over them.



Then the top plate gets bolted to the top of the uprights.



Next, the gusset is bolted to the top plate.



Next, attach the blade holder to the bottom of the jack plate with three bolts, then, secure the blade with the six set screws.



 

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Looking good, I use mine a lot and it's nice having the press brake separate from a press too... so if you don't have two presses I suggest it highly :)
 

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Now bolt the bottom die to the base plate, place a 1/4" thick spacer between it and the blade. Position it as straight up and down as possible then clamp or tack it in place.



Next, remove the springs and slide the blade down into the bottom die to check the fit. If all looks good tack the four gussets in place on the jack plate. (oops...forgot to mention making those earlier). Now comes the fun part, welding it together without racking the slides to the point of binding on the uprights. The only advice I can give on this is to jump around doing small sections at a time. Mine did rack a little bit but I was able to fix it by pulling it apart and running a wheel cylinder hone through them a few times.



Yes, I know the weld on the left looks bad but the pic makes it look worse than it is. The welder started having wire feed issues for some reason.



With it all put back together it should look something like this.

 

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Discussion Starter #8
I used my old 20 ton jack when this was being mocked up and tested but will be using a 12 ton jack as stated earlier, probably a air/hydro from H.F.

These are the first test pieces. The material is 1/8"x3" 1018 cold rolled. Now keep in mind that I machined the die to a 100° angle to be able to compensate for spring back. I will be making differant angle dies in the future.





I found this site that has drawings of alot of differant die and blade profiles that could easily be adapted to use with this press.

http://www.midwestpressbrake.com/index2.htm

Click on products to bring up the drawings. Example:

 

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Discussion Starter #9 (Edited)
Crap, I almost forgot to add these to the thread.







This drawing below does not include the measurements for the "v". I will leave that up to whomever builds it to decide what they want.



 

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I have made 2 brakes simular. for the clean up die just rotate your 2X2 solid square 45 dergees. one big problem - the steel is soft and you gotta watch what you bend or the dies will deform. nice work.
 

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the female portion of the die sure looks like hot rolled to me. did you consider using something harder for the dies?
 

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the female portion of the die sure looks like hot rolled to me. did you consider using something harder for the dies?
You're right, it is hot rolled. When it came time to make that piece, the piece of cold rolled I had, had disappeared. Turns out that my dad had grabbed it for something he was working on. From here on out, the rest of the dies will be cold rolled.
For the amount of work that will be done with this, the cold rolled should be just fine. If not, I'll have some made from A-2 or 4140 pre-hard on the e.d.m machine at work.



Straight8: I have made 2 brakes simular. for the clean up die just rotate your 2X2 solid square 45 dergees. one big problem - the steel is soft and you gotta watch what you bend or the dies will deform. nice work.
Originally, the first one was made for making parts for a 3-point hitch on my dads' garden tractor, most of which did not need to be bent anywhere near 90°. Believe it or not, the old one has been used quite a bit and shows very little wear, but I haven't had to bend anything harder than cold rolled.



Thanks to all for the compliments.

Finally got it painted today.

 

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I have several lengthts. mine were in good shape till I bent some 3/8x 1 strap. he he nice little notch! if that happens just weld it up and grind er smooth.
 

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excellent tech-!!!

great design and build..!

just a note if you already didn't know:

for bending in a press brake (either a big one, or a small one)

if you need a tighter bend than the machine will do, put some hard flat rubber
stock between the V-die and the work peice. the rubber will deform and
allow a tighter-degree of bend.

--free advice is exactly what it's worth..!

--Sherpa
 
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