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making U shaped brackets

SuperUPer

Plastic
Joined
Mar 30, 2019
I have an opportunity to get into supplying U shaped saddles for deck beams and posts. The material is 3/16" mild steel, four different sizes to fit 4x4 and 6x6 lumber. One short style bracket with 4 nail holes per side and one tall with two 1/2" bolt holes (short and tall for each post size). I have made a few prototypes doing three pieces and welding the tab ears, and while this does not take long, I would like to speed it up by doing one piece bent up. I do not have bending capabilities as of yet but am considering purchasing/ building a shop press and custom dies to press these in one stoke. Blanks are cut out on the cnc plasma table, holes included. Press brake will probably be in the distant future, but takes up too much space in the current shop. Which is why I'm leaning towards a shop press and custom dies. I did a quick die prototype that I tested on a shop press at my day job, would work well with some tweaking.

So I'm looking for press recommendations. Or help building one but I think what I want is pretty complicated. I would like some kind of stroke limiting to be able to bend consistent 90 degree bends. The only presses I have found that have this built in are Iroquois Iron (just limit switches I think) and Edwards (electronic PLC control). Has anybody added something like this to a shop press? Kind of leaning towards buying something due to already being slammed busy but it would be a neat project to learn on. The frame and welding would be simple for me, the hydraulics a little less so, but PLC programming I know very little about.

Really digging the Edwards press but its $11,000 plus a nearly $4,000 power unit. This is not totally out of the budget but it's definitely higher end. Found another press brake style shop press called Prolinemax but can't find any info on it. Seems odd that the website selling it sells everything from industrial tools to couch cushions and tactical clothing. Probably junk but who knows

Things to keep in mind:
these brackets would likely invoice around 20K/ year
don't require tight tolerances
one man show
part time business (not exactly tiny, did 100K in invoices this year)
in AK, shipping gets spendy
240V single phase available
7.5hp air compressor on site
480v 3 phase generator (for the plasma, easily switchable to 240v)
would most likely get into some heavier bending, probably no more than 1/2"
 
I had your machine all ready to go, but your last statement killed it. How thick are your brackets you want to bend?

What you need to do is define exactly what you want to do as far as thickness and sizes because bending 16ga, 1/8, 1/4, 1/2, all require different setups.

How many will you be bending? You say this would bill out 20k a year, but is that 50 or 5,000 brackets or 50,000.

My first thought was to build a very simple brake for a 20 ton shop press. If you build it with all 90* dies, you can basically just keep bending it till 10 tons of pressure shows up and your all done. I will post a picture of my 50 ton shop press brake with a quad die. This allows me to bend from 1/8 (down to 16ga but larger radius) up to 3/8" thick. I can make repeatable bends even at 60* angles with it. Also know I have over 10 years of press brake experience.

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If your making a "Square U bolt" which what I think your doing, you should be able to cobble up
a simple "bulldozer" rig, and with some scraps, make the punch & die.

I would give it at least 50 tons, 100 would be better.

No PLC needed, ram continue to closure of die.

EDIT: Please post a drawing of what part your trying to make.
 

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Easy enough to do in one piece with proper tooling. Trumpf press brake would certainly blow your budget. The two punches with ears I am using are about $600.00 each. 3 quick strokes and done. Those are 16 gauge, and have also made special brackets from .120 SS304, last pic. Those brackets hold my back door deck. They bolt to the foundation and the dack does not touch the siding. I call it a deck, but only 48 x 104 and a few steps off the ground.
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If these are for treated lumber mild steel wouldn't last long down here. I don't know about corrosion in the cold.

I don't think you are going to bend two 90 bends at the same time without better tooling. Bottoming the punch may get you close enough with a small dimple in the bottom of the bend. A swing on one side of the die could wrap that side around to make the sides parallel. But its possible to do with a simple hydraulic set-up and bottom the punch.
 
A wiper style tool will do both bends in one stroke, but you can't get 90 legs without some extra bits or a second station. If you can add darts (dimple) like Gbent suggested you might get them to 89.9 degrees which is probably plenty good enough for the application.


Cheapest option would probably be a short bed mechanical press brake and a dedicated tool.

Many of my parts have U-shaped mild steel bends done in one hit in wiper style press tools.
 
If I were doing this I would make a punch clearanced for the part to swing back through and do it in two separate bends. We make many parts that way, actually.
 








 
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