Maleing radius bends on a standard leaf break

[burninbriar]

I thought this might be of help to any one needing radius bends in sheet metal.
For my head light project I need 7/8" radius corners. I used 1 1/2" black pipe, it is about 1 11/16" od and cut a 12" section lengthwise. Then welded a 1/8 x 3/4" piece of flat to the edge of the cut for the nose bar of the break to sit on. then welded in a 1/8 x 1 1/2" peice of flat to brace the pipe section and provide a stop for the nose bar. Finally I welded in an other 1/8 x 1 1/2" flat to brace the unit and lock it in place on the nose bar. The second picture shows it snapped into place. The next photo shows a bend in 20 guage made in 2 peices, the cuts were not squared up so thats why it looks kind of funky, I was mostly worried about the edge. In the last foto is a 90 degree bend in 20 guage scrap. I couldent get the head back far enough to make a full 90 but with a little modification I will have that taken care of. It was relatively quick and easy to make and I hope some one can use my thoughts on there own project.
I guess you cant edit the title, sorry for the terrible spelling.

[N20Silverado]

I couldent get the head back far enough to make a full 90 but with a little modification I will have that taken care of. ng.

Please show us how you over came this problem. I modified my brake and am having the same problem. Only 1/4" radius though.

Thanks.

Tim

[burninbriar]

I'll get some picture later, right now I have to go to a funeral viewing for an old freind. Basicly I'm going to have my freind, (not the dead one), machine the adjustment slots 1/4" longer.

[N20Silverado]

I'll get some picture later, right now I have to go to a funeral viewing for an old freind. Basicly I'm going to have my freind, (not the dead one), machine the adjustment slots 1/4" longer.

Sorry for your loss.

No rush.

Thanks.

[tallwelder]

Burningbriar, looks like You are going to get that radius figured out, looks good so far. Another approach I have done is lay a piece of angle iron face up in a hydraulic press then lay the sheet metal on top, then put a piece of heavy wall tube or bar stock centered above the angle. Press a nice almost 90 degree angle into the sheet. Carl

[burninbriar]

tallwelder :
I would love to have a press. I've been thinking of building one but unless I can find used material that will work its out of the question for now. New steal would cost more than buying a press allready made.(cheap one)

N20Silverado :
Thanks for the condolences.
Heres some pictures of what I want to do. The first pic is just a side view of the brake. Second shows the 1/4" the adjuster can move before bottoming out against the threaded lug on the left. The last pic is the adjuster block with the clamping bolt removed. You can see where the threaded hole is right at the edge of the slotted hole, I can either drill & tap a new hole in the center of the slot or have the slotted hole elongated an other 1/4". I'm leaning toward elongateing the slot, I wont be removeing enough material to substantially weaken it. To give some perspective, The slot is 13/16" wide by 2" long and there is 1 3/8" stock to the right of the slot. takeing 1/4" will still leave 1 1/8" stock to the right of the slot.

[jolane]

First, sorry for the loss of your friend.

Second, great job on the bend! I am currently in the design proces of a press that has the ability to double as a press brake. It will not be inexpensive as the hydraulics are not cheap. I want something heavy duty though, and fairly accurate. Anyways, it is great to see how you would bend a nice radius on a leaf (finger) brake! Thank you for sharing.

Joshua

[burninbriar]

First, sorry for the loss of your friend.

Second, great job on the bend! I am currently in the design proces of a press that has the ability to double as a press brake. It will not be inexpensive as the hydraulics are not cheap. I want something heavy duty though, and fairly accurate. Anyways, it is great to see how you would bend a nice radius on a leaf (finger) brake! Thank you for sharing.

Joshua
Thanks for the kind word.
I would like to see what you come up with for youre press, I really need one. I have to go to my neibors when I deed to use one now and I live out in the sticks, my neibor is a couple miles away.

[jolane]

Just some ideas for my press...

1. It will probably look like a press brake, but with ~6-8" of travel. I would like to make a universal interface to bolt attachments to. This way I can bolt tools like round bars vertically (bressing out bearings), horizontally (radius bends), V dies (sharp bends), and the like.

2. I would like it 4' wide working width, enough to bend a sheet across basically.

3. The upper cross piece that moves will probably move on linear bearings are the ends to keep its motion straight. These will probably be very simple plain bearings.

4. I would like electro-hydro, but manual power would be fine also I guess. I am working on the mechanism to more the upper head up and down while staying parallel and in alignment to the lower table. The linear bearing may be enough (just use a single cylinder), but all bending would probably have to take place in the center of the machine. I do not plan to use a bottle jack though (but it could happen because of cost). I keep looking out for the cylinder I want (~6" diameter, 50 ton maybe...)

5. The lower cross piece moves up and down like a regular press. When bending, a table could be fit into the lower cross brace to hold the lower dies.

6. The lower table could have adjustable stops built in for different bending setups.

It will probably be very large and heavy. I would also like to mount my tube bender off the side of it one day, and share the hydro power unit. Again, these are all just thoughts right now. Price is the main killer, the cylinder I want is very expensive...

I know this may just be more confusing than anything, but those are some of the ideas I have had...

Joshua

[burninbriar]

I have heard of people useing an adapter to fit press brake dies in a shop press, but I'm not sure how they deal with makeing both sides come down evenly. That could be why it never really caught on, I know if they dont come down even you will never get a satisfactory bend.
What youre talking about is more than I think I can handle money wise and space wise but I would be interested to see what you do. Ideas are like gold.you never know when you might be able to use a peice of something youve seen.
It sounds like you basicly want the top head to act like a press brake and the bottom half to function like a shop press. If you did it like that you could possibly make a top die adapter that would hold a hydolic piston for pressing bearings and such.

[Twocentsworth]

This is the way I did it on my press. Mostly the stuff in red. Basically, I saw the idea somewhere and did it with a couple of modifications. The die holder on top is just three pieces of 1/2 inch plate plug welded together. They are staggered to hold standard dies. 1/2 inch plate is bolted to the sides to keep the top die straight as it comes down. Springs pull the die back up to assist the single acting cyclinder. FWIW, it seems like it took about 28 tons pressure to bend the piece of 3/8 X 5 inch plate in the picture. I might be misremembering or my gauge might be wrong. Other pictures of dies to bend round corners and some misc. dies. Hope this helps if you decide to build one like this. Sorry if this is a thread hijack. I can still use this as a regular press by using attachments in the top die holder.

Twocentsworth.

[burninbriar]

No highjack what so ever , I didnt post looking for advice, just to share knowledge. Youre right on target.
Do you get an even brake left to right ? Looks pretty nice.

[jolane]

Pete,
Yes, making the sides move equally is the challenge. This is where I have been looking at several types of mechanisms to accomplish this, but in the end, since this is for a home shop, it is probably not necessary. I can always bend in the middle...

Twocentsworth,
Thanks for the pictures. Yes, this is what I was thinking as well. That is very close to what I was picturing other than I will probably use round linear bearings at the ends of the upper die mount to guide it.
Do you have any problems bending evenly across the die? Have you bent anything full width yet, and if so, how uniform was the bend across part? 28T is a lot of pressure. My understanding is that the lower die controls the bend radius in the part, and therefore the pressure required to bend the piece. I think the general rule is something like 8* material thickness for the lower die V width.

Did you make your press too? If so, what hydraulics did you use?

Thank you for sharing. It definitely helps in my confidence level that what I want to do it reasonable and will be effective in the end. I don't need a 4' wide shoppress, I need a 4' wide shop press/brake! The brake aspect was the unknown.

Joshua

[Twocentsworth]

Quote from burninbriar:

Do you get an even brake left to right ?

As far as I can tell it works well. I never have bent anything full width so don't know how much that top die would deflect. I did not make a bottom die holder. It seems to work out just to put the bottom die between a couple of pieces of plate and line it up by eye. It almost seems to self center a bit.
Here is a link to some die information. They changed the site. I think you have to download the catalog. It shows what is available and can give some ideas. On page 6, it shows some radius bending.
jolane,

I did not make the press. The limit of my knowledge on the width of the dies is the thicker the metal the wider the bottom die needed, so what you said about the width sounds good. There have been many people that have made their own bottom dies out of angle. I bent about ten of these brackets in the picture which were 5/16 x 3 inch. Once I got on to the positioning of the top die on my marks, the repeatability was right on. As I recall, it took about 6-8 tons pressure to bend them. Slow going with these hand press machines, but it does work.

Twocentsworth

[burninbriar]

Nothing bad looking about those bends. I would think you could bottom out youre dies empty and then clamp blocks around youre bottom die to keep it from moveing if you have a lot of bends to make. I have worked on a regular press brake before so I do have some knowledge of the dies, although most of my work in the past has been with a strait leaf. I see dies on ebay a lot that seem to go pretty resonably priced.

[jolane]

Some more food for thought... I was also hoping to build mine such that it could use other "tooling" to turn it into an English wheel. I don't think that this would be too difficult to do. The pressure could be applied just like a typical english wheel, through the lower die with an acme threaded rod. In this same manner, I think I could also make a set of dies to turn it into a rolling machine. Maybe one set of dis could be used to roll sheet stock, and a different attachment to roll tubing.

My machine could end up like a Smith workshop (is that the name?). Again, for my environment, this would be perfectly acceptable to tear down a setup to do a different process.

Twocentsworth,
That bracket looks great. That is the sort of stuff I can envision needing to do, plus long bends in thin sheet stock (fuel tanks, angle, etc). On the lower die, yeah the size is important and related to the tonnage required for bending. Are you air or bottom forming? Bottom forming requires a lot more pressure.

Joshua

[Twocentsworth]

I don't know if I'm air forming or bottom forming. When I bend some Aluminum 6061 T6 for box shapes etc. I use a top die with a radius since I have heard 6061 likes to crack. It still could be cracking, but I have not seen it with old and half blind eyes. :) I did a dye test on one just to check and it was OK. Mostly, with the steel I bend I am just shooting for an angle and really don't care how I get it. BTW, these dies will overbend a 90 so care has to be taken as it's easier to bend a little more than unbend. To check a bend and bend a little more, I just back off the press just enough to slide the piece out the side, check with a square, replace, and try to go farther if not bent enough. It takes a little practice to understand the machine, dies, and metal being bent, as each may have a little different springback etc.

The English wheel idea would probably work, but would be limited be the press uprights. Also, with hydraulics, even if the cylinder bottomed, there always seems to be a little play or give, so not sure how that would compare to something purely mechanical.

Don't know what to say about the roller idea. I guess if space is limited, or if a person is so inclined, there is almost nothing that can't be done.

Picture of Aluminum box.

Twocentsworth