My DIY press brake

[Joe Blaze]

Since I saw a few posts here on press brakes, i decided to post my project of putting together a DIY one from mostly scrap i had laying around.

Here is my cheap solution for my need to find a way to bend some ¼” aluminum diamond plate for some brackets I needed to make. I made it after seeing some examples of DIY press brakes online. The die I made from an old piece of ½” thick railroad scrap I found at the local Rail Road crossing.

The 3/16” x 1 ½” and 3/16” x 2” angle iron and ¾” round bar I had left over from other projects. The ¼” steel base plate I cut from the edge of a larger piece I was using as a welding table top. The round pipe was scrap left over after relocating some steam radiators in my house.

I cut the railroad scrap down to about 12" x 2½” with a cheapo 4 ½” Harbor Freight/Northern grinder with a good quality cut-off disk. I started out by using my plasma cutter on it, but found that the low-tech method of using the grinder and cut-off wheel worked better, leaving a beautiful clean edge.

I then used the plasma at an angle to get a rough point along the edge, and then finish ground the point with another cheapo grinder with a grinding wheel. (They are so cheap, I keep four, each with different disks and brushes on them for different needs. It is easier than swapping the disks.)

I cut two pieces of the 1 ½” angle iron to the same length, and welded them, butted up against each other to form a c-channel, almost to the edge of my ¼” steel plate. Then I cut the ¾” bar to two pieces of the same length. These got welded into the angle iron to act as structural support to go underneath the bottom die.

Then I cut and welded a piece of 2” angle iron to be the cradle of the brake.

After aligning the top die to the bottom of the angle iron forming the base, I cut two pieces of the pipe and welded one to each side of the die.

Then I cut some more ¾” rod for the pipe on each side of the die to ride on, and welded them in place on the ¼” base. I used a cheap grinder attachment from Northern that turns it into a mini chop saw.

(to be continued in next post due to image count limitations)

 

[Joe Blaze]

(continued from previous post)
The top gets slid onto the posts, and that’s it. I welded it along the edge of a larger piece of 1/4" plate i am using for my welding table, and just cut the edge of the plate off the table when I was done. (The table fits better in my garage now). I will add suitable springs under the pipe on each side when I can scrounge some up somewhere. In the mean time, it works for me. It bends 3/8” flat stock like butter

 

[TheBeast_88K5]

sweet!

 

[tRustyK5]

Couple of things that'll get you even nicer results would be to radius and polish the top edges of your lower die. Then spend some time on your upper die doing the same.

Some general rules of thumb for press brake die sets: 1) the throat of the lower die (top edge of your angle iron to the other top edge.) should be 8X the thickness you are bending. 2)The radius on the upper die should be equal to the thickness of the material you are bending.

If you look at the pic of the bar stock you bent you see a very sharp bend line. That area is now considerably weaker and crack prone.

Not really necessary in a hand pump shop press, but die sets can take a major beating. I like to add some hardfacing and then polish. If you have a stick welder there are literally hundreds of hardfacing rods out there that'll do the job. My favorite was a rod called "Hardern Helle".

http://www.hardern-helle.com/

The last die set I built was for a 120 ton centrifugal brake. 10" throat, 3" diameter 4140 upper die, 18" width. I'd bend 1" x 8" mild to 90 degrees. I had a 3/4" radius at the edges of the lower die.

 

[bigjbear]

Nice. What are you using for the ram?

 

[Joe Blaze]

Couple of things that'll get you even nicer results would be to radius and polish the top edges of your lower die. Then spend some time on your upper die doing the same.

Some general rules of thumb for press brake die sets: 1) the throat of the lower die (top edge of your angle iron to the other top edge.) should be 8X the thickness you are bending. 2)The radius on the upper die should be equal to the thickness of the material you are bending.

do you mean that the top die would be better with a radiused edge, rather than sharp? i can actually see where that would give me less of that sharp bend. that would be better.

 

[tRustyK5]

Yes, you only want a really sharp upper die for very thin material, like less than 1/8" thick. Radiusing the bottom die allows the material to slide into the die easier and with less gouging on the backside of the material.

For thicker stuff like 3/8" you can just stitch weld a length of 3/4" round bar to a plate with guides...

 

[Joe Blaze]

Yes, you only want a really sharp upper die for very thin material, like less than 1/8" thick. Radiusing the bottom die allows the material to slide into the die easier and with less gouging on the backside of the material.

For thicker stuff like 3/8" you can just stitch weld a length of 3/4" round bar to a plate with guides...

Thanks for that advice. i could make a new one and have two dies to use depending on the bending job needed. that will probably have to wait for the spring. i crammed my garage with crap for the winter.