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Looking for Brake Press Ideas for Large Radius Bend

m_ridzon

Plastic
Joined
Feb 7, 2021
I'm just a weekend hobbyist. I have access to a large press to bend sheet metal (e.g., my project is 3/16" thick steel). However, the press does not have a die set to make a large radius bend. In other words, it will only make bends with a tight radius. But my project needs a 1" radius. I'm looking for ideas to for how to get this large radius, without having to go buy a die set.

For reference, the attached Google image kind of shows what I'm trying to do.

(So far, I have not been successful tracking down a local weld/fab shop that could make the bend for me)

Thanks in advance!
 

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m_ridzon

Plastic
Joined
Feb 7, 2021
The bend needs to be 90°. The length of the bend is about 1.5'.

I like the idea of round bar with some flat bar tacked to its top. What about the bottom side, under the steel plate? Will a "V" shape do okay on the bottom side?
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
The bend needs to be 90°. The length of the bend is about 1.5'.

I like the idea of round bar with some flat bar tacked to its top. What about the bottom side, under the steel plate? Will a "V" shape do okay on the bottom side?

You're way overthinking this.

Punch made of roundbar push material into V. Width of vee is important it matches your punch so you can get to 90
 

Rob F.

Diamond
Joined
Aug 5, 2012
Location
California, Central Coast
Like garwood said, the width of the vee just needs to be wider than 1" so the 1" top die can get down inside it to give you 90º bend.
Only 18" long it is a no brainer to make the top die, if you can get a short piece of 1" round. Cold roll would be nice but not critical.
 

Mcgyver

Diamond
Joined
Aug 5, 2005
Location
Toronto
can we assume very low quantities since its a hobby? (with anything, quantity is as important to the solution as material and dimensions)

top die is easy, and the bottom doesn't have to be a long ground V die. When required for a short run we fabricate specialty dies like below and it works. Width of the bottom die has to suit material, thickness and radius of bend

However if you've got a shop that has the tooling and will do it, there's your solution

ApllHC5.jpg
 

kustomizer

Titanium
Joined
Aug 17, 2007
Location
North Fork Idaho
Like garwood said, the width of the vee just needs to be wider than 1" so the 1" top die can get down inside it to give you 90º bend.
Only 18" long it is a no brainer to make the top die, if you can get a short piece of 1" round. Cold roll would be nice but not critical.

He wants a 1" radius meaning a 2" bar, way too wide to use any "V" die I have ever seen, but that don't mean they don't exist
 

m_ridzon

Plastic
Joined
Feb 7, 2021
He wants a 1" radius meaning a 2" bar, way too wide to use any "V" die I have ever seen, but that don't mean they don't exist
You are correct in that I need a 2" diameter bar. I'm going to inspect the vee that's currently on the machine and see if it will work. But nevertheless, you make a valid point that it needs to be wide and able to handle the pressure.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
Cincinnati mechanical 400 ton press brake, with a pit for the lower die holder.
The whole place shudders when in motion.
 

kustomizer

Titanium
Joined
Aug 17, 2007
Location
North Fork Idaho
Well, by golly gee, that there's a press brake, or break depending on who is setting it up. Mine was 56 tons mechanical and scarry for me. I have one of these now, it is more my speed
BPU412-6-HandBrake.jpg
 

MCritchley

Hot Rolled
Joined
Mar 22, 2007
Location
Milwaukee
Cincinnati mechanical 400 ton press brake, with a pit for the lower die holder.
The whole place shudders when in motion.

Mechanical! That would be intense to run.

We had a 60 ton we called the widow maker, it was faster than our hydraulic presses- good for production
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
He wants a 1" radius meaning a 2" bar, way too wide to use any "V" die I have ever seen, but that don't mean they don't exist

I use a 4" V die section on my friends 100 ton regularly bending 1/2" steel. It just about kills two of us getting it in the machine even with the forklift, but it's sure nice to have.
 

Bondo

Hot Rolled
Joined
May 14, 2011
Location
Bridgeton NJ
You cant "really" bend a 90* bend with a radius in a standard 85* V die. To use a 2" round punch with 3/16" material, you would need roughly a 4" die. You need a very strong bottom die that can handle wall pressure to do the final 5*.

Your best bet is to build a custom die set with 3 rounds like what was previously posted. This allows for the pressure to be applied in the proper locations to do a 95* bend which will flex back to 90*.

That custom die set in the OP first post is CRAZY expensive. I priced out a 12' set for my brake for 1/8" stainless and it was in the 20k range, and that was 4 years ago pricing. Best dies for stainless though.

Sent from my SM-G960U using Tapatalk
 

m_ridzon

Plastic
Joined
Feb 7, 2021
Where there's a will, there a way. It took a while since life got in the way, but I built my own jig and was able to bend the plate. It worked out great!

press_1.jpg

press_2.jpg

press_3.jpg

press_4.jpg
 








 
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