Bending 1 x 3 HR bar

I read K Potters thread on press brakes. Nice info.

I would appreciate some guidance on what is involved with the 8X die rule.
I have a 50T Geka ironworker that has the tooling for a press brake set up less the V die.

I have a need to bend some 1 x 3 HR bar and would love to use this press if possible. My Geka came some tooling the mounts to the punch end. The largest die is made from 2" round bar.
So with all this said, walk me through what is needed to build a v-block die. I invision a heavy plate with two pieces of round bar spaced x" apart to accomadate the material, 1.0" bar plus my 2" round bar tooling...

Where do I go from here?

Thanks,

Tom

I dont think you have the tonnage.
I bend stuff like this on the hossfeld, hot, and it works fine.
Cold, though, most press brake charts tell you that with 50 tons, you need a V die 12" wide to bend 1" thick material. That is for one foot of it, but the tonnage to bend a 3" wide piece, cold, would still require that you have your bottom V die at least 6" or more apart.
Press Brake Tonnage Table from American Machine Tools

What that means is a very large radius bend. And you would need the bottom die parts to be much taller than 1" diameter to get up to a 90 degree bend.

Hot, though, you could do it more like what you are thinking. Got a forge? Or a rosebud for an oxy-acetylene rig?
Of course, hot, you would get impressions from your die. Which is why people air bend hot- no die marks.

I built a 100 ton h frame press and I am able to bend that kind of stuff with about 50 tons it is a big radius bend but it gets it done.

Thanks guys.

Ries, I do have a coal forge that has sat idle for years. The rose bud seems like my best option.

Ruff rule of thumb for mild steel is the die is 8x the thickness wide, measured at theoretical tips of the V (8" in your case) The top tool needs to be a radius of a minimum of 1x thickness. Think a 2" piece of round bar for your bit (bright mild steel is probably not strong enough - will deform at these pressures in my experience). The edges of the V ideally need at least half the thickness of material as a radius, but more is nice.

Increasing all of the above make's it a fair bit easier - less prone to crack. You can go smaller than 8x on the V, 4x is about the limit though. But tonnage goes up massively, and the V will really start to bite into the work piece. Go smaller on the top tool and it will start to cut into the work + massively increase the likely hood of cracking.

Heat makes it a lot easier, even just a good black heat can really reduce the forces involved by more than half. Problem is heat can - will affect bend angle hence you will need to tweak it for each piece if it needs to be accurate. Heat will also let you get a lot sharper bend too which can be important!

While it won't help you with your bend, here are pics of a brake that I made from scrap around the shop. I put it on my 50 ton Scotchman. It might give you some ideas for future bends.
Using a forge for your bends would be easy to set up. Putting a couple fire brick to direct the heat so you could set the metal on the brick. Rosebuds are wonderful but need to be handheld.

HELLO,
what DEGREE OF BEND? this has not entered into
the conversation. but i think this is very important.
good luck to all.
wlbrown

90 degrees