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View Full Version : what is a suitable steel to make a press brake



michigan doug
05-25-2013, 09:56 PM
I am thinking about making a press brake to go with my 50 ton press.

What would be a suitable steel?

I suspect that the steel might cost me more than a used set of dies. True or false? I want something about like

what Keith Fenner is using on this video, which is pretty instructive if you haven't seen it:

http://www.youtube.com/watch?v=qzmO2VI9l6E

You see it on the press at about 5 1/2 minutes.


finest regards,

doug

macona
05-26-2013, 12:41 AM
Boy, the upright pieces on that press sure seem light for 50T

You should be able to find used press brake sections on ebay or at a local section. It is nice to have small sections since you dont always want to bend a full length. You may have tabs sticking out or something like that.

Forrest Addy
05-26-2013, 03:35 AM
Press brake punches and dies take fierce local loading. Mild or structural steel if used to make presas brake punches and dies will work a short time but the crisp radii progressively bruise and deform eventually producing unsatisfactory bends. There are press die manufacturers who maintain comprehensive tutorials on their website.

There's been many home shop people who made a little press brake die set for use with their with their bottle jack presses - or on even a smaller scale in mill vises. These can produce very satisfactory work in light gage materials. I've made press brake tooling. It's nice work but it involves funny angles easy to acheive on a planer or shaper but a little tedious on a turret mill.

You will probably wish for some form of solid stop to be employed to prevent over-bending. These stops can be as simple as a piece of all-thread at each end arranged to limit die closure.

Materials can be quite simple. Structural steel for most all the parts except for the loaded portions of the punch and die. You'll get good service from pre-heat treated 4140 for the actual punch and die. Shop around and you will find specialy steel upplies serving the press brake dia manufacturers. Ask for a "rem" a remnant left from a long bar that was cut to length. Most cut to order shops have stacks of rems waiting for buyers. Don't be shy abour bargaining.

Maybe use Tompson ground stock for the posts and run them in bronze bushings. Needless to say when using a home made press brake die set on a shop forcing press you need to center the bend precisely under the press ram.

This outfit seems to know their stuff but they aint cheap. Their prices for even short lengths of punch and die section are far beyond my wallet.

http://press-brake-products.fabsupplyinc.com/category/conventional-precision-planed-press-brake-tooling

Maybe used stuff and remnant stock sections on eBay

http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR2.TRC1&_nkw=press+brake+die&_sacat=0&_from=R40

Jaakko Fagerlund
05-26-2013, 03:57 AM
Boy, the upright pieces on that press sure seem light for 50T
Those probably handle the 50 tons each, the stresses on them are quite easy compared to the horizontal beams and thus can be calculated very easily.

lazlo
05-26-2013, 04:14 AM
Most presses (including Keith's) are made from structural steel (i.e., A-36).

Brake dies are typically heat treated 4142. A tad more carbon than 4140. I doubt you'd notice the difference.

macona
05-26-2013, 04:20 AM
Those probably handle the 50 tons each, the stresses on them are quite easy compared to the horizontal beams and thus can be calculated very easily.

Tensile, yes. But I would expect it to flex somewhat laterally when there is an uneven load.

Jaakko Fagerlund
05-26-2013, 07:54 AM
Tensile, yes. But I would expect it to flex somewhat laterally when there is an uneven load.
Yup, uneven loads behave like chaos if trying to anticipate them while designing the thing. Looks like the press in question wasn't designed for uneven (or better yet, sideways) loading but to merely press things that won't behave erradically.

As to the OP question, structural steel is quite sufficient if you just want to do occasional this'n'that. If you want to go fancy, then prehardened stuff for the dies so that they last a little longer. And even fancier is propely hardened tool steels, but for the life of I could not find my reference book for the suggested hardness on press tools, as too hard will shatter like glass. Safe to say that anything between 30-45 HRC works.

vpt
05-26-2013, 08:53 AM
Wow that guy has a ton of videos and all great stuff!

darryl
05-26-2013, 06:31 PM
For my home made brake I used structural steel for the male and female parts. It doesn't get used in a workday setting, but I have put it to a lot of use. The parts are starting to show some deformation, but not to a great extent. I'm sure it would be better to use 4140 or similar. This particular brake has a capacity of 14 inches, and I have bent 3/16 thick material in it, but not at that width.

I've made another brake with less width capability, but with a 12 ton jack. The die parts are structural steel again, and I've bent up to 1/4 thick material in it- again not at full width. The die parts do suffer, particularly the male part (the knife). At some point I'll replace it with 4140, but I think I'll get a couple years out of it as is.

Both of these machines are made to guide the movable part (which is the bottom, the V) in a straight line up and down, so there isn't a stringent requirement to keep the part being bent strictly centered, though I still do pay attention to that. I think that's just good practice anyway.

Incidently, both these home made machines will outperform the 3 in 1 I have in all regards except width, which is why I built them. The 3 in 1 has a more durable die and press plates, but just does not give as nice a bend.

mixdenny
05-26-2013, 06:51 PM
I see you are in Michigan. If you are close enough to venture a trip to HGR Surplus in Cleveland, they have racks of press brake dies selling by the piece or the pound, not sure which it is. Dennis

http://www.hgrinc.com/buyOurs/inventorySearchResults.do?searchlog=Y&sel_word=press&sel_word_sub=%27PRESS%27&sel_inventory_num=&sch_word_chk=1&sch_word=&sch_word_sub=%27%27&sel_start_dt=&sel_end_dt=&sel_category=&sortBy=4&sortYN=1&pageLine=10&sessionUrl_pass=N&viewMode=list&currPage=1&inventory_num=&addList=&cust_id=&sch_yn=Y&buttonView=1&sel_start_price=&sel_end_price=&priceMode=direct

HAP
05-27-2013, 08:05 AM
I got the press brake from Northern Tools and found that my ram was too large for the top ring. It yeilded under 28 tons. Beefed it up with some heavier steel I had. Also had to replace the springs because the extra weight of the steel caused the opening to close up a bit.

R,
HAP

http://i890.photobucket.com/albums/ac106/HAPSHOP/IMAG1140_zpsf9acfddd.jpg (http://s890.photobucket.com/user/HAPSHOP/media/IMAG1140_zpsf9acfddd.jpg.html)
http://i890.photobucket.com/albums/ac106/HAPSHOP/IMAG1142_zps920a766c.jpg (http://s890.photobucket.com/user/HAPSHOP/media/IMAG1142_zps920a766c.jpg.html)
http://i890.photobucket.com/albums/ac106/HAPSHOP/IMAG1148_zps7975b0a8.jpg (http://s890.photobucket.com/user/HAPSHOP/media/IMAG1148_zps7975b0a8.jpg.html)
http://i890.photobucket.com/albums/ac106/HAPSHOP/IMAG1119_zps5ec0365d.jpg (http://s890.photobucket.com/user/HAPSHOP/media/IMAG1119_zps5ec0365d.jpg.html)

michigan doug
05-27-2013, 08:56 AM
Wow that guy has a ton of videos and all great stuff!

Yes, yes he does. If you watched all his videos two or three times, and paid attention, and took some notes, you could go from rank beginner to fairly sophisticated home machinist in a short time. Not quite like having your own apprenticeship, but almost.




Thanks for all the info. I knew you guys would know all the juicy information.


doug

wtrueman
05-28-2013, 03:50 AM
Darryl: Do you have acess to a used grader blade? That might be what you want for the male part of the press. Wayne.

randyjaco
05-28-2013, 08:14 PM
I built this one for my non-Harbor Freight press. It works very well
http://www.swagoffroad.com/20-TON-Press-Brake-DIY-Builder-Kit_p_40.html

Randy