Bending Brakes radius bend

[Red_Barn]

Hello,
I`m trying to re-create a metal box frame from WW2 german radio made of 22ga steel. The problem I ran into I can`t bend the steel plate and get a similar sharp edge as on existing original box.






Initially I got a cheap Bending Brake from Eastwood but the radius angle I was getting was almost round





I tried to google but there is no info on as how to get small radius bending.
I read some good reviews of Woodward -Fab and sent them a sample to bend on their 24" Box and Pan Brake. The results was a little better but still not close to original sharp edge.





Can anyone recommend a good bending brake that will give me a small radius bend? My longest strip is 13" in 22ga steel. Budget is under $1K.

 

[RivennHewn]

Can you adjust the distance between the fences on your brake?

Usually you can adjust the part that bends up closer to the part that clamps down on the metal.

 

[PugetDude]

A small press brake (or even a HF press) with a set of sharp v-dies will do it. That's probably how the original was done. The problem is most of the inexpensive sheet metal brakes have a 1/8" bend radius- easier to bend at the maximum stated capacity.

The other way to get a really crisp bend would be to V-score the inside of the cut with a cutoff wheel before bending- (about half way through)- give the material a place to go besides into a fat radius.

 

[ilovevocs]

I would find someone to press break a few 8' to 10' pieces for you and modify them to length as you see fit. I don't think your going to get a bend that sharp on a brake. The edges actually look coined IMHO.


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[kursplat]

wonder if the originals were stamped...

 

[machine_punk]

The other way to get a sharper corner, is to lay on side of the angle on a flat table, use a 90-degree dollie (heavy chunk of steel used for shaping metal) on the 'inside' of the angle and a flat body hammer on the outside. Where I was trained to do sheet metal, this was THE way to get a sharp corner on sheet material.

Kev

 

[WWIIjeep]

What you need is a good old-fashioned brake or bar folder with a cam adjustment that allows the leading edge of the clamping bar or fingers to move closer to the bending leaf (apron). With such adjustment, you'll be able to achieve near-square bends on 24 GA with little or no radius.

Pexto, Niagara, Diacro and Chicago brakes and bar folders all have that kind of adjustment.

 

[APEowner]

I wonder if you could just use some angle stock.

 

[thinmac]

+1 on machine_punk. I have done a quicker and dirtier method along the same lines with great success.

Find a table you can clamp to (I've used a welding table) that has a sharp corner and some thickness to it. Place your sheet metal with the line you want to bend on the edge and clamp a piece of tube or solid bar on the end over the sheet metal. Then, take a hammer and slowly bend it over - bend the whole length of 30°, the the whole length to 60°, an so on. The tube, or solid stock, and the table hold it tightly so the part on the table doesn't move, and the sharp corner minimizes the radius of the bend. All in all this means you don't have to buy any expensive equipment.

 

[Red_Barn]

Can you adjust the distance between the fences on your brake?

Usually you can adjust the part that bends up closer to the part that clamps down on the metal.

Yes, this was done with the max adjustment to get the smallest bending radius.

 

[Red_Barn]

I would find someone to press break a few 8' to 10' pieces for you and modify them to length as you see fit. I don't think your going to get a bend that sharp on a brake. The edges actually look coined IMHO.


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Lol, good idea! My local shop charges $120/hr. 2.5 hrs to bend 300 small pieces. I thought might well buy a new machine and do it myself but if I can`t find a solution I`ll just make them bend 40 pieces @ 4' long for under an hour

 

[Red_Barn]

wonder if the originals were stamped...

 

[Red_Barn]

The other way to get a sharper corner, is to lay on side of the angle on a flat table, use a 90-degree dollie (heavy chunk of steel used for shaping metal) on the 'inside' of the angle and a flat body hammer on the outside. Where I was trained to do sheet metal, this was THE way to get a sharp corner on sheet material.

Kev

+1 on machine_punk. I have done a quicker and dirtier method along the same lines with great success.

Find a table you can clamp to (I've used a welding table) that has a sharp corner and some thickness to it. Place your sheet metal with the line you want to bend on the edge and clamp a piece of tube or solid bar on the end over the sheet metal. Then, take a hammer and slowly bend it over - bend the whole length of 30°, the the whole length to 60°, an so on. The tube, or solid stock, and the table hold it tightly so the part on the table doesn't move, and the sharp corner minimizes the radius of the bend. All in all this means you don't have to buy any expensive equipment.

Come on, there must be a better way . Hammering on 22ga I will never get them perfectly straight.

 

[Red_Barn]

A small press brake (or even a HF press) with a set of sharp v-dies will do it. That's probably how the original was done. The problem is most of the inexpensive sheet metal brakes have a 1/8" bend radius- easier to bend at the maximum stated capacity.

Can you suggest any machines under $1,000? Max 24" in length?

 

[Red_Barn]

The other way to get a really crisp bend would be to V-score the inside of the cut with a cutoff wheel before bending- (about half way through)- give the material a place to go besides into a fat radius.

Hmm, I`ll give it a try ... if won`t find a machine.

 

[ilovevocs]

Lol, good idea! My local shop charges $120/hr. 2.5 hrs to bend 300 small pieces. I thought might well buy a new machine and do it myself but if I can`t find a solution I`ll just make them bend 40 pieces @ 4' long for under an hour

Why not go with min. 8' lengths. The materials readily available in 8' and 10' lengths, the press break will handle either, and you will reduce the bend count to 20. If I were doing this I would bend them at full lengths and then bring them into size with my iron worker.


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[machine_punk]

Come on, there must be a better way . Hammering on 22ga I will never get them perfectly straight.

I disagree...it takes a few minutes, but I've done this many times on 18ga material. In fact, it was one of the first things we learned at the Contour Autocraft course (the guys who were selected to create the copper petals for the English Olympic opening ceremonies)...where we ended up with a part of a classic XK Jaguar fender, and a couple of other sample pieces, to take home at the end of the week. Pretty much the first 'hands on' lesson there was, "here is how you get a sharp corner on sheet metal bent to an angle." We later turned that into a wire edge, but we had to form a perfect 90-degree flange on both an inside and outside curve first.

I've seen it done and I've done it. Maybe I'll have to post a 'how to' in my thread.

To the OP...I am definitely interested in seeing more pics of what you are working on.

Kev