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DIY Press brake / Sheet metal folder


Bowie69

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As some of you know I'm about to embark on a voyage of Morris Minor rebuild, so lots, and lots of sheet metal work, I will not be using any pre-made repair panels, it is no concours project!

So.... for making long bends in sheet metal (or in fact short ones) the industrial thing to have is a press brake, google it and be scared by the prices! :)

I didn't have that kind of wonga, and looking about, for something that will sit in a vice, or bolted to a bench you are looking at the thick end of £150 for a cheapie one, about 450mm wide, to bend 2mm, which I will need to do on the Moggy.

So.. thought a lot, and bought a 20T hydraulic press instead. Logic dictated this I assure you! First it is something I have never had, but often wanted.... second it will help with aspects of the Moggy build, and third you can build a press brake to sit on it with a bit of ingenuity.... The press has a 500mm opening, wider than most, got from ebay, recommend the seller, http://www.ebay.co.uk/itm/151773286004

So, some scrap 8mmx60mm steel, two Rover V8 gudgeon pins (pressed out with the new press-woohoo!) and could of bits of scrap angle iron and a piece of tube and wound up with something that looks like this:

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Couple of things to note, I have it sat on the V-blocks only for the final bend, but even so with the 8mm bottom plate, sat on the 10mm piece barely flexed. Also, this was a first attempt so I am not saying this is how to do it, just my take on a first design.

The 'knife' was sharpened with a 4.5" angle grinder with a thick grinding disk in it.... took a while, but came out well. I sharpened to over 90 degrees to allow for springback of the workpiece.

The 'valley' was formed with two pieces of angle, one side of each I shortened about 2.5mm (again with a grinder, just a slitting disc this time!) so when sat on the base plate, they would form an angle of less than 90 degrees between them, again to allow for spring back. Side effect is I suppose you may want to do something tighter than 90, so could always help :)

This is how I did the guide, saved finding two steel tubes the right diameter to fit inside each other:

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This cap head bolt just secures the top of the brake to the usual pin on the press, so when you take the power off, it takes it up with it. The press bears directly on the 8mmx60mm 'knife', so it doesn't bear any load. I drilled and tapped the press pin as high up as possible, and will leave the bolt in there when doing other pressing duties.

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This is it all together:

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So of course I had to try it.... cue one Morris Minor chassis leg in 1.5mm steel:

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This was a first attempt, and only marked up quickly with a sharpie, it took me about 20 minutes to make it once I had cut the workpiece out. With practice, and measuring the piece out properly with CAD (frosties style) I am sure even quicker, and I will be able to put that awkward final fold in place before I find I need to stand it on V-blocks to fit it round the tool....

Folds come out pretty well! Certainly good enough for my needs.

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So... over to you lot, criticism, as long as constructive is fine, in fact I welcome it ;) Tips on using etc also fine! I know I need practice :)

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It look's a good job! something I keep meaning to do for mine actually. It looks from the photo as though the middle isn't bent as sharply as the ends - optical illusion?

Thanks, and yeah I think it is, widescreen cameras do funny things with their lenses... just been out to double-check and the gap compared to a tiny square I have is the same all along it's length, even the one where I had it up on vee-blocks.

Meant also to say, the couple of coils of springs will be taken off next time it is off the press, was trying to avoid having to fit it to the press pin, but actually it works very well this way!

I *do* have some black paint.... no blue though!

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I wonder how easy it would be able to adapt to different length folds, say if you wanted to fold a tray type shape?

Not quite sure what you mean...? I can do quite a good Z-fold already, that what you mean? Sorry if I am just being thick :)

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I looked at building a sheet metal folder last year. In the end though I decided to buy one because I need to fold sheet steel over 900mm wide. However I do like your logic! I also have been wishing I had a hydraulic press for a long time, and I thing that I will buy one soon.

You will have to post a link to a rebuild thread for the moggie. I am sure we would all be interested to read it.

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I thought I'd worked out what Gazzar had meant, then Ross comes along and confuses me again.... :P

Then I read cynic-al, and I think people on here mean a 'cube' rather than a box, which I took to be a box section (I was very confused as I knew all I had to do was fold the last one the other way....!)

Yes, if you could remove fingers like you see on posh ones then I am sure you could make cuboid-boxes ;) If you google SWAG off road press brake you will see some DIY kits from the US, that looked pretty good, apparently able to bend 12-15" of 1/4" plate... bit overkill for me, but I am sure handy for many LR people.

I did think about an electric pump, but to be honest, once the knife is in place it is only 5ish pumps before the bend is done, assuming you don't go too far up after a bend it's not far to come back down, so having now used it, I don't think it really worth it :)

Re: Build thread, I will think about it... the moggy is still on it's side in the rain (today at least) awaiting me attacking it with a grinder and welder, though I have almost all the suspension refurbed, painted, new bushes, brakes, uprights built etc all ready to go on once I can make it a rolling chassis again, currently has no front or rear suspension at all, except the top leaf of the rear springs(!) (both of which had cracked leaves).

Thank you people... you are too kind :)

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Paint it blue, say it cost £200!

Nice start. I wonder how easy it would be able to adapt to different length folds, say if you wanted to fold a tray type shape?

I think if I wanted to do this, I would get some more steel and make something a bit more posh, with bolt-in knives.

Like this, from SWAG: http://www.swagoffroad.com/20-TON-Finger-Brake-Heavy-Duty-DIY-Builder-Kit_p_86.html

If I was in the states it would have been a no-brainer, I would have bought a kit, but this was all FREE :)

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That looks good. I'm yet another in the "I want one" camp! A press is one of those tools that you don't need often but when you do it's normally with a degree of urgency. My panel forming normally involves some hardwood, hammers and swearing.

Heads off to eBay for a look.....

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I've got a v block and a blade but they are separate so I have to line them up which can be a bit 10 handed. Works well though and I can do folds into corners (which I think is what gazzar means). I've folded small bits of 1/4 with mine so I reckon you could do about a 3" long fold in 1/4 in the middle of yours.

Mike

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Yep probably right Mike, I've certainly not built it to be bullet proof, it has to bend one type of thing -sheet metal up to 3mm, which I am sure it will do without bother.

If I want to bend thicker stuff I'll probably build something a bit bigger/heftier and not out of scrap (unless very lucky!), and with a narrower/adjustable knife width. I doubt the current 8mm bar would put up with 6mm stuff for very long....

I looked at building a sheet metal folder last year. In the end though I decided to buy one because I need to fold sheet steel over 900mm wide.

I thought about the length issue, and decided if I needed to I could just weld stuff together, or if it became a real problem, I just built a new folder at 1m wide, and sit it in the press at an angle. Being able to fold full stop is so much of an improvement I doubt it will cause me any headaches with longer stuff :)

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was just starting to sketch up ideas for a sheetmetal brake of my own. i dont need anything massive, however i know full well that when i come to use it i will want it bigger/with more configurational options etc. so at the moment it looks quite elaborate (almost as much as a full on proper brake)

This looks quite a neat solution. one i have used before at my previous job and it also results in an excuse (finally) to buy a press!

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  • 1 month later...

You inspired me to have a go so when I had a bit of time at work I dug through the offcut pile and knocked this together. There's room for improvement but it hasn't done bad for a first stab. I didn't want a square fold so I welded a bit of round bar onto the pushing edge. That's a bolted on bit of angle so I can make a pointy one at some point.

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Stainless exhaust bracket for my mot :)

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4mm thick x 400mm wide mild steel.

20151021_205023_zpslztshrke.jpg

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Very nice al!

Definitely a bit more heavy duty than mine, gave a nice curve too? Also like the extension pieces that wrap around the press frame, should help keep it nice and square, something, if I forget to lock the press off properly, that can be a bit annoying is re-aligning the gudgeon pins and the guides. Think I need to find a way to hold it down after release to stop it coming off the top of the pegs....

Oh, and I want access to your scrap bin! :)

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I put the round bit on as I didn't want to bend too tight for that job. I'm going to make a pointy bit like yours at some point.

Your pins will be more accurate than my flat bits on the outside of the frame, there's a bit of play in them but it seems ok. I had to slice one side to get them in too which is why it looks a bit messy. Didn't think about that at the time! I need to see if I can scrounge any old bolsters from work as the steel I used to pack the base up isn't as stable as I would like. Initially it was going to be supported on the dowels but there isn't enough stroke on my press for that to work :(

I call it my offcut section not my scrap bin ;)

They don't like me keeping clutter so I have to hide it well. Generally they buy for a specific job and don't like to keep the left over bits as there isn't space and it rarely gets used. Like my little fabrication table. That came as part of a lot from auction when they wanted a robot, I was supposed to scrap it but I managed to keep it hidden for 10 years before I found a use for it and converted it ;)

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