Author Topic: Metal bending  (Read 876 times)

Metal bending
« on: June 08, 2019, 10:01:28 am »
Anyone know if sheet metal rollers (the cheap sort with 300mm width and likely 1.5-2mm capacity) would be any good at rolling 6mm round bar? Is there a specialist tool for it?

Re: Metal bending
« Reply #1 on: June 08, 2019, 10:14:45 am »
what are you trying to do, exactly?

cheers

Re: Metal bending
« Reply #2 on: June 08, 2019, 11:35:22 am »
If they are the ones with grooves, they will do curves of radius down to about 100mm, however I wouldn’t bother, even though I have access to some.

I would either do it freehand in an engineer ‘s vice, or make a jig if I had a few to do.
If it ain't broke, fix it 'til it is...

Re: Metal bending
« Reply #3 on: June 08, 2019, 08:35:35 pm »
I want to roll circles of c 30 cm diameter, and also possibly along 2 axes ( think making a globe from S shapes)  for garden plants. Probably with 6mm rod. Plus other stuff, but that's more nebulous.

Re: Metal bending
« Reply #4 on: June 08, 2019, 09:20:17 pm »
If it was me, I'd try to do it with a jig.

If I get time, I'll have a go at work on Monday - it's easier than trying to describe how to do it.

Do you have a router, or smomething to cut a circle from plywood/MDF?
If it ain't broke, fix it 'til it is...

Re: Metal bending
« Reply #5 on: June 08, 2019, 10:17:02 pm »
6mm dia bright mild steel can be cold-formed quite easily using wooden  or metal jigs. Because it work-hardens slightly, it is easier to form smooth, constant radius bends than you might expect.  Even a very simple tool (eg comprising a ~7mm dia hole in a piece of 1/2" thick steel plate, held in a bench vice) can allow you to make the bends you want in easy stages; friction will hold the work well enough as soon as you start to bend the 6mm rod; just make a slight bend, push the rod further through the hole, (and twist it slightly if you want the part to be a complex shape), another slight bend, and carry on. The closer together the bends are, and the more the steel work-hardens, the smoother the end  result will be. 

The ~7mm hole needs to be large enough to allow the curved rod through the hole and if necessary to withdraw the work. I would say that you will get enough leverage to bend 6mm rod provided you have a length to hold that is at least ~12" long. With practice you can make all kinds of 3D curves this way, whereas with many other methods you can most easily make curves in a single plane only, and you need a revised jig every time you want a different radius. With other types of jig the curves may be perfectly consistent; however for certain types of work, part of the charm of it is that the parts do vary slightly.

  If you want to make the most  complex shapes, it is often easiest to make simpler shapes and to weld them together; for example the 'S' shapes could be fabricated from two simpler 'C' shapes, which could be made using a fixed type jig.

cheers

Re: Metal bending
« Reply #6 on: June 08, 2019, 10:23:23 pm »


With a bit of practise it's possible to get quite replicable results with a set-up like the above. You don't say what sort of metal you're wanting to work with, but I was doing scrollwork with some flat steel bar, so you can put a bit of welly into it if you can get the leverage (you can also use the same principle to make a tool with the above but with the bit the prongs are attached to extended as a handle).

Having the tools and materials to make the doobrie left as an exercise for the reader...

fuaran

  • rothair gasta
Re: Metal bending
« Reply #7 on: June 08, 2019, 10:43:26 pm »
A plumbers pipe bender tool might work. They are usually designed for 15mm/22mm copper pipe, so might have to add some sort of spacer.

Re: Metal bending
« Reply #8 on: June 09, 2019, 08:29:31 am »
I'm wanting to  bend mild steel, the sort of end product is like this - not a replica.


or this



IME, bending curves is easier than bending circles, which is where a roller might well help. However, even if it works for 6mm, I was wondering about 8 or even 10. The two axes thing is to end up with a globe.

Re: Metal bending
« Reply #9 on: June 09, 2019, 09:17:50 am »
10mm mild steel is workable cold, so long as you have a sturdy and heavy enough bench/vice to push against.

I was considering something like this: https://www.indiamart.com/proddetail/manual-tube-bender-conduit-pipe-bending-machine-7725277555.html could be made in timber if you were doing 6mm.

If you are going to 10mm, you could make something like the EMT benders you used to be able to get in the US and use the ground as a fulcrum:



One problem with rollers, is you probably will need to do more than one pass to roll the curve, so you will have to keep changing the radius settings.
If it ain't broke, fix it 'til it is...

Re: Metal bending
« Reply #10 on: June 09, 2019, 09:57:12 am »
You would be surprised at how easily you can make complex shapes using the scheme I have  outlined above.  If you want to see what can be done, make a half-sized model (eg drill a ~3mm hole in ~1/4" thickness steel to make the tool and then use it to bend coathanger wire). You may find this handy to trial/mock up your designs anyway.

If going to 8mm or 10mm steel then the easiest thing is probably to heat the steel to dull red heat before bending it. An alternative is to use tube rather than solid; this isn't as strong (so bends a bit more easily) but is quite likely to crumple if you load it in the wrong way. It is also quite a bit more expensive to buy.

cheers

Re: Metal bending
« Reply #11 on: June 09, 2019, 09:58:04 am »

One problem with rollers, is you probably will need to do more than one pass to roll the curve, so you will have to keep changing the radius settings.

Why do you see this as a problem, I would have thought it relatively simple process?  (genuine question, as I haven't done any serious metal bashing for upward of 40 years)

You would be surprised at how easily you can make complex shapes using the scheme I have  outlined above.  If you want to see what can be done, make a half-sized model (eg drill a ~3mm hole in ~1/4" thickness steel to make the tool and then use it to bend coathanger wire). You may find this handy to trial/mock up your designs anyway.
I may well give it a go

Quote
If going to 8mm or 10mm steel then the easiest thing is probably to heat the steel to dull red heat before bending it. An alternative is to use tube rather than solid; this isn't as strong (so bends a bit more easily) but is quite likely to crumple if you load it in the wrong way. It is also quite a bit more expensive to buy.

cheers

I suspect I will leave 8/10mm as uprights.....

(although 8mm bends may be viable)

Re: Metal bending
« Reply #12 on: June 09, 2019, 10:13:14 am »
This looks to be the business https://www.baileighindustrial.co.uk/manual-roll-bender-r-m3-1 - wonder what is out there second hand.

From what I can make out (and I suspect this is the question I should have asked) the cheap and cheerful little sheet multi tools I've been looking at (on my phone as I've been AFK for the last week) top out at 5mm rod capacity.

Re: Metal bending
« Reply #13 on: June 09, 2019, 11:21:44 am »

One problem with rollers, is you probably will need to do more than one pass to roll the curve, so you will have to keep changing the radius settings.

Why do you see this as a problem, I would have thought it relatively simple process?  (genuine question, as I haven't done any serious metal bashing for upward of 40 years)

An already bent rod will sit differently in the rollers, so it becomes a challenge to get the adjustment you want: if you use trial and error on one piece and then use that final setting on another rod without the same intermediate jibbling, you won't necessarily get the same result.


caerau

  • SR x 3 - PBP fail but 1090 km - hey - not too bad
Re: Metal bending
« Reply #14 on: June 09, 2019, 02:09:48 pm »
Am I the only one who thought about Yuri Geller when I saw this thread title?  :D
It's a reverse Elvis thing.

Re: Metal bending
« Reply #15 on: June 09, 2019, 06:33:59 pm »

Re: Metal bending
« Reply #16 on: June 10, 2019, 08:31:17 pm »
Am I the only one who thought about Yuri Geller when I saw this thread title?  :D

Yes I was half minded to state that Ham needed a Geller. I started in engineering/gear manufacturing/rolling mill when a yoof and they certainly had big bendy things.
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