Ring rollers – anything known?

[Robin GrahamParticipant @robingraham42208]

A number of eBay vendors are selling ring rollers like this:

They are branded differently, but clearly the same tool with minor variations.

Some, but not all, vendors say the tool will produce rings from 1" diameter upwards but in the tech specs they all give a minimum bend radius of 7 cm.

Can anyone advise as to the what the minimum radius actually is? To give an idea of scale, vendors seem to agree that the tool is 18 cm in height (excluding handle). Seems unlikely to me that the tightest ring it can it can do is 140mm diameter, but I have never used bending rolls so can't really judge.

Robin.

[Robin GrahamParticipant @robingraham42208]

[oldveloParticipant @oldvelo]

The minimum diameter will depend on the material you wish to bend. Working in a jobbing shop we rolled everything from Armour Plate a total pig to anything less than 5 times the roll diameter to soft brass that was 1.25 the roll diameter was quite easy to achieve.

For up to 8 mm round stock you can use the spring makers method and wrap the on a mandrel in the lathe with snubber block in the toolpost.

Eric

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Robin Graham on 21/08/2020 22:20:14:

[…]

Some, but not all, vendors say the tool will produce rings from 1" diameter upwards but in the tech specs they all give a minimum bend radius of 7 cm.

[…]

.

That ^^^ seems to be the claim which needs questioning

How can something with a minimum bend radius of 7cm produce a ring of 1” diameter ?

MichaelG.

[JasonBModerator @jasonb]

Posted by Michael Gilligan on 22/08/2020 07:37:28:

How can something with a minimum bend radius of 7cm produce a ring of 1” diameter ?

MichaelG.

That would depend on thickness of material, how far you can close up the rollers and roller diameter. One would hope they quote for same case but giving the smaller size will sell more tools.

eg if rollers are 1" dia and will only close up to leave a 1/4" gap you could in theory roll 1/4" material to a 1" dia but 16" material could not be rolled as tight, some calculation would be needed to determine actual bend which I can't be bothered to do.

[Michael GilliganParticipant @michaelgilligan61133]

So what does a “minimum bend radius of 7cm“ mean then ?

… sorry if I’m being dim, but I thought it must mean a minimum bend radius of 7cm

MichaelG.

.

Edit: __ My guess is that 7cm should read 7mm … and is a reference to the ‘bottom’ radius of the groove in the wheel.

Edited By Michael Gilligan on 22/08/2020 08:09:57

[JasonBModerator @jasonb]

Well that is what the OP is asking.

Interestingly both RDG and Chronos sell these and throw a third anomoly into the works with a 3" ring diameter and 1" bend radius. may be worth contacting them.

I can also see that you would get different bends on round stock to flat as the ring groove cut into the rollers would affect what is possible so maybe they twist sizes quoted what sounds the best

[Michael GilliganParticipant @michaelgilligan61133]

So we are now discussing things described by respectable U.K. suppliers, rather than [verboten] ebay sellers

… but confusion still reigns

MichaelG.

[not done it yetParticipant @notdoneityet]

How can something with a minimum bend radius of 7cm produce a ring of 1” diameter ?

Perhaps there might be “optional extras’ of smaller diameter wheels available, if the machine has sufficient adjustment for the rollers?

One, at least quotes the diameter of the wheels as 7cm. One shows a pic of a 180 degree bend (of 7cm diameter inside diameter if flat bar) – but that would not be the minimum radius of a complete ring. So I expect their claims are about right in that a ring in max diameter (of material) is not possible at the roller diameter of 7cm. Thin stuff (not much thicker than we might term ‘wire&rsquo might be a different matter.

The jargon/detail used is basic, and likely worded that way to befuddle dim purchasers?

[Michael GilliganParticipant @michaelgilligan61133]

Robin

There is one version on ebay [listed as SwitZer] which has copious illustrations, and is currently on offer at £44.99 with free U.K.delivery. … You might find sufficient information there to decode those cryptic descriptions of the machine.

MichaelG.

[Martin ConnellyParticipant @martinconnelly55370]

Probably a badly translated specification regarding inside diameter, outside diameter and centre line diameter. In reality what can be achieved depends on material spring back and physical size together with the size of the rollers and their relative positions. These given values will change if the rollers are replaced with something of different size. Does it come with interchangeable tolling to suit different material sections? If so the given sizes may be minimums for two different sets of tooling. Here are some rolls I made for aluminium tube.

Martin C

[Dave HalfordParticipant @davehalford22513]

Posted by Robin Graham on 21/08/2020 22:20:14:

A number of eBay vendors are selling ring rollers like this:

They are branded differently, but clearly the same tool with minor variations.

Some, but not all, vendors say the tool will produce rings from 1" diameter upwards but in the tech specs they all give a minimum bend radius of 7 cm.

Robin.

I imagine you could roll the 70mm ring, but you wont get it out of the groove so less than half ring only.

The wheel must be just less than1" dia to slip a 1" ring off

[Robin GrahamParticipant @robingraham42208]

Thanks for replies. I was hoping that someone might have used one of these tools, but that was a long shot I suppose.

Thanks for pointing out the Chronos offering Jason – I hadn't lit on that. Although not consistent with the eBay vendors I think it's possible that their specs can be cudgelled into internal consistency. They say that a 1" radius is "achievable" , so maybe 2" diameter is the best case scenario and 3" diameter a more typical limit. That seems more reasonable than the discrepancy between a 1" diameter and a 70mm radius

The descriptions of the various eBay offerings are very similar to each other – it looks like they are all copied from the same source, so it may be that there are translation errors in the source document. In fact, if one transposes radius and diameter, the eBay specs read 1" radius and 70mm diameter. Not so far off the Chronos specs.

A quick Google reveals that that the Chinese have one ideogram which represents range, scope, extent, limits, radius, and another that represents path, diameter, way. So anything might happen! Any Chinese speakers out there…?

On the basis of this perhaps specious reasoning I have ordered the SwitZer which MichaelG pointed out. I want to roll 1/8th CZ108 brass (not armour plate oddly enough) so I'm hoping I can get somewhere near 2.5" diameter.

I'll report back when it arrives.

Robin.

Edited By Robin Graham on 22/08/2020 20:02:01

Edited By Robin Graham on 22/08/2020 20:03:08

[Robin GrahamParticipant @robingraham42208]

Arrived today.

The Chronos spec is correct: 1" is the theoretical minimum radius (hence "achievable" I suppose) but 1,25- 1,5" more reasonable given spring. I think radius and diameter have been transposed in the eBay specs. So fine for my purpose – 7cm radius wouldn't have been tight enough.

Robin.

[Nigel Graham 2Participant @nigelgraham2]

If you are looking for fabricating equipment I'd have no qualms buying from "our" regular suppliers though it's other tools I have bought from them.

For sheet-metal handling though, you could also try WNS, in Rochford, Essex. They make a range of sheet- tube- and bar- rollforming tools from small manual up to big industrial machines. They sell some 2nd-hand machines, too, though it's not their main business.

I write just as a satisfied customer, once for a second-hand Warco bench-drill, second time for one of their own, new, manual, swaging machines (a form of tin-man's jenny).

And no, I am not their on-line "influencer"!

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