Thinking of building a press brake. Looking for opinions.

[RockRanger]

To go with my plasma table I am looking for a decent way to bend metal. I built a small sheet metal brake awhile ago and for thin guage stuff it works fine. I am looking for thicker materials and wider widths. Let me preference this by saying I know you will always want bigger. I started by seeing what was on the internet. I quickly realized the commercial ones were way to expensive and big for a mostly hobby machine in a 3 car garage. I started looking at home built. There is the SWAG press that goes into a HF press or build your own frame. It is a possibility I haven't completely given up on. I also found two others that caught my attention. First is BERSK on Pirate4x4 http://www.pirate4x4.com/forum/torchmat ... oject.html While it is cool and I have seen it in person it is still pretty expensive and big. The second is Jamscal laminated brake in a HF press. http://www.pirate4x4.com/forum/shop-too ... a-new.html It is cool cause of the flexibility his has but you are limited by the width of the Press just like a swag kit. You are also limited by the pressure of the ram.

I started looking around my garage and 99% of items I would want to bend were under 1/4" and under 3' wide. I started drawing up a press that s 3' wide and my plan is power it by a 20 ton air over hydro ram cause they are cheaper then going full hydro. Looking at press charts 1/4" mild 3' wide with a 3" lower die is 27.3 tons. Using some mechanical advantage that could be possible to achieve with a 20 ton ram.

I am looking for opinions if it is strong enough or will I kill myself from an explosion if I build it. The plan is the main frame, bell cranks, shackles, ram mounts will be cut out of 1/2". The Dies would be cut out of 1/4" plate. The lower die will sit on a piece of 1"x2" on each side and the gussets under it would be cut out of 1/4" The bell crank arms are 8" from the pivot to the shackle and 12" from the pivot to the ram mount.

Overall view.

BRAKE 1 by Matthew Dresselhaus, on Flickr

With some dimensions.

BRAKE 2 by Matthew Dresselhaus, on Flickr



How the dies are placed. They will be laminated together. Based on the dimensions I saw on ebay some normal dies could be purchased and used as well.

BRAKE 3 by Matthew Dresselhaus, on Flickr


Before I go spend a $1000 on material and turn it into scrap I have a few questions.

1. Is the 1/2" frame strong enough or is there going to be to much deflection in it?

2. Am I right that due to the ratio change in the arms of 1:1.5 the 20 ton ram theoretically become 30 tons of pressure at the die?

3. I was thinking of using 1" grade 8 bolts at the pivot points with 1.5x.25 tube bushings sleeved thru the arms. Should do something different here?

4. Are there any areas that I have grossly overbuilt or under built?

5. How much weaker would it be if I cut it all out of 1/4" plate? The parts I have drawn as 1/2" would be cut twice and stacked to make them 1/2" thick.

6. Anyone have any comments suggestions or changes I should make?

[Capstone]

Obviously you've thought this through and the plans look very good.

I happen to have the HarborFreight 20ton / SWAG Offroad HD Fingerbreak setup, which I put on wheels. I haven't had to bend anything super thick or really wide yet, but I have made pretty good use of the set up.

There's the fabricator side of me that says go for it and build something yourself. It's super rewarding to use your own tools. But I don't know enough about the forces involved to attempt something like this, so I guess I will just have to take your word for the figures. If they are wrong and something terrible happens, your life insurance policy probably won't pay out. , but that said... I can't see there being anything cheaper with the same expected capabilities and if you have the $1000 and really see a reasonable ROI for that expense in the added capability, I say go for it. One other option is of course to buy a used older model and repair/refurbish it, that way you'll have the rated specs defined a bit better.

I definitely haven't seen my ROI on the press brake set up I have, yet, but I balance that against the total expense and the experience of welding it up myself and having a new tool to experiment with on new projects. Whichever way you go, keeps us in the loop to see your success (or maybe failure ) so we all learn something.

[sodfarmer]

I also have a swag kit for bending heavier stuff. It works good for 1 off heavier stuff. For my lighter materials such as 10 gauge and thinner I have a Bantam 4 foot 12 ton press brake. I put a cnc back gauge on it for production parts. With the cost of the brake, building my cnc backgauge, and replacing a few things i have around $2,500 in it. I liked the ability to use production punch and dies. It would be nice to have one with more tonnage, but the setup I have works good for me. The majority of what I bend is 10 gauge and thinner.

[RockRanger]

Do you have a writeup or info on adding the cnc backguage? That is one thing I wouldn't mine looking at being able to add.

[sodfarmer]

I haven't done a write up of my cnc backgauge. I'll get the info on what I used and some pictures and post them the next couple of days.

[RockRanger]

That would be great. Thanks

[Capstone]

I have a Bantam 4 foot 12 ton press brake. I put a cnc back gauge on it for production parts. With the cost of the brake, building my cnc backgauge, and replacing a few things i have around $2,500 in it.

You put out that you spent $2500 on this setup, either that's a typo or you probably should add that there's no way anyone else could simply go out and buy (or even build themselves) this setup for that dollar amount and I'll just add a much deserved "you suck" because you got the deal of a lifetime.

A new Bantam 4 foot 12 ton brake costs $7500 without a CNC backguage and the first used brake (and I mean USED) I found on eBay with the same specs was $4000.

[sodfarmer]

The $2,500 is correct, was just a case of right place right time. I was kind of leary when I went to look @ it, thought it was a case of to good to be true. I know this normally isn't the case, but deals can be found if you look and when you find them, you need to pull the trigger. I looked for over a year to find the one I bought. I missed out on a 4 foot 24 ton Bantam just before this, it was $2,500, still kick myself to this day for that one.

[Capstone]

So I will concede that it is possible to find a good deal. I'm not in the market for a press brake, here's one I found that maybe someone else might want to get.
$2500 Press Brake in Maryland

[tnbndr]

There is a press brake build similar to what you are proposing on Pirate 4x4.
http://www.pirate4x4.com/forum/shop-too ... o-tna.html

http://www.pirate4x4.com/forum/torchmat ... oject.html


I have one of these and use the brake option the most. I purchase short dies on ebay and fabricate specialty ones myself.
http://www.metalprocorp.com/32/MP4500FS-Ironworker

[illusivedf]

I have a 40 ton shop press with a brake attachment I was using for production now mainly just custom 1 off bends. I also have a 2ft 12 ton bantam I use it to bend 1/8", 3/16", 1/4" and 3/8" thick parts with the correct lower dies it has just enough power to do the parts I build in the widths that I need. If I need a wider part I can just use a larger lower die if need be. I almost never use even half of the width of the machine. I just have some 16" wide dies right now and some of my biggest parts do not need anything wider than that. I wish it had a CNC backstop and ram depth though, would make setup faster but it gets the job done once set and all parts have uniform bends. I drove a few states away to get it but bought it used for about 1/4 of what they cost new and it was in very good condition.

[cbassjr]

I guess I'm missing something but I'm sure we all have 12 ton mostly 25 ton plus presses in our shops. Why are none of you looking at the drop in press brakes for these or is it you've just got to have another expensive toy. Not trying to be an ass here but all the widths and thickness, etc you all are specing are available in these and more plus you don't have to justify a loss on you roi and be a lot safer. I know I build or invent on the fly a lot of my own stuff but I also am willing to buy when there's a potential safety issue. Also these drop in press breaks are easy to build and if you go that route a whole lot cheaper than where you are at at this point.

[Metriccar]

I bought a SWAG DIY 20 ton press brake and couldn't get it to work right. The center of the bottom die expanded so I couldn't get a uniform bend out of it. It's just angle Iron you weld into a c channel piece of metal.

I then bought this one: http://www.ebay.com/itm/SUPREME-14-Pres ... 33a4656f6a


I am more than happy with it. It has a better backstop-the SWAG one was just a flat piece of metal that had a concave so you had to put whatever you were bending at exactly the same place on the backstop otherwise you'd be putting the bend in a different area on your metal. The backstop on this one is one that has a fold in it which helps keep it straight. The bottom die is also a solid v grove channel that has been machined. I personally will never buy a SWAG product again because of my experience with the press though a lot of people seem to like them.

I won't bother trying to do anything other than simple 90 degree bends though, and really don't find much value in a 20 ton hydraulic hand pump with a shop press other than simple bends where accuracy and consistency are not critical. I believe a hand pumped bottle jack press brake compared to a cnc press the equivalent to a hand torch to a CNC plasma table. Almost a joke, really, other than you can get repeatable bends for whatever happens to come out at 90 degree angles when you max out the bottle jack.

[Capstone]

Metriccar, I wish I had seen this before I got my SWAG fingerbrake. I agree with your assessment of the brake. I got the DIY kit. I wanted to change over to a air/hydro jack, but now I'm rethinking. I think the finger aspect definitely changes the versatility on my set-up, which most others don't have, but maybe I will likely sell it once I have a bigger space to move into.

[rikduk]

A dedicated press brake vs a diy using a bottle jack is bending faster, faster setup, more precise, and usually more capacity lenght wise.
I've got a 110Tx 10ft pressbrake, 30yrs old, with ram stop and backgauge, and even though i wish it was cnc, i still couln't live without it.

Rockranger, your design looks good, i saw a big company using links like that to move the ram, very simple way to make the ram go down evenly without fancy hydro/electronics.
I would only add an adjustment between the two top triangles to adjust the ram levelness.

Richard

[gdj966]

http://www.northerntool.com/shop/tools/ ... _7902_7902
http://www.northerntool.com/shop/tools/ ... 1896_21896
For thicker than 12 ga. I use these in my shop presses with a 20 ton Air/Hydraulic jack. They work well for me.. They will bend what they advertise them to..

[sodfarmer]

Here are some pictures & pricing for my back gauge:
4 axis motor kit:$249.99-ebay
linear rails:$111.91-ebay
acme screws:$99.25-ebay
misc-$20
computer-$100-local purchase

I had the steel and built my own brackets with my plasma table. It's nothing fancy but does the job for me. The most challenging thing was figuring out the manual for wiring the axis kit. Its right around +/- .010" for tolerances. I use mach 3 for driving the axis kit.

Sorry for the delay.