Interlocking bangles

[bruggen]

I’ve been asked to make three interlocking bangles like a huge Russian wedding ring. I will be using 3.2x1.9mm oval sterling silver wire. The bangle sizer I have is numbered and she wants a No18, this equates to a 65.07mm diameter though it measures 65.4 with a calliper.
My question is what formula do I use to get the right size, as an engineer teaching metal bending we used the formula pi x d+1/2t, with rings I normally use pi x d+t where d is diameter and t is thickness, pi being 3.142, I have assumed that for three interlocking bangles they should be pi multiplied by the diameter plus three thickness’ is this right, I don’t want to mess it up.
Any advice would be much appreciated, I’ve bought enough metal to have two attempts just in case.

[josef1]

I always find it a bit of a mystery trying to work it mathematically. I did it in cad and got the wire length to be 232.7mm thats a 65mm diameter
13534.13533

The pink line is the size circle I used the size of wire you specified. I would maybe make it up in 2mm copper wire first to check

[Dennis]

Basically, the three intertwined hoops must pass over the folded hand, and must each be quite a bit larger than a single hoop.

There is no published formula, but if you take Joseph's suggestion and make it in copper first there'll be no disaster, but a starting point for further adjustment, if needed.

When I have done this for a finger, the size of the three rings used was three English sizes bigger than for a single ring. Dennis.

[Ruedeleglise]

Basically, the three intertwined hoops must pass over the folded hand, and must each be quite a bit larger than a single hoop.

There is no published formula, but if you take Joseph's suggestion and make it in copper first there'll be no disaster, but a starting point for further adjustment, if needed.

When I have done this for a finger, the size of the three rings used was three English sizes bigger than for a single ring. Dennis.

Thanks Dennis. Was just about to start on a 3 rings commission
and you have answered my question before I could ask it!
David


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[bruggen]

I always find it a bit of a mystery trying to work it mathematically. I did it in cad and got the wire length to be 232.7mm thats a 65mm diameter
13534.13533

The pink line is the size circle I used the size of wire you specified. I would maybe make it up in 2mm copper wire first to check

Wonderful, thank you, there must be a mathematic formula though, I did nearly get the same result as you, my calculation was the diameter of the first bangle plus three times the wire diameter multiplied by 3.142 the number i got was 223.7mm, I have ordered some copper wire and pass it through my roller and try your calculated length and see what size I get, if its then too big I can always reduce the bands. Thank you again, I will let you know what I get.

[bruggen]

Dennis, oh no, if anyone would know I would have bet money and put my faith in you, I have read conflicting descriptions of making three band rings, I think I took your advice on that with the three sizes bigger, there was a different description and that was a multiplicand that ramped up exponentially depending on the number of rings, I can't find the reference now, I have ordered some thicker copper wire and will try to roll it down to more of an oval shape and attempt it as josef1 suggested, as always I thank you.

[Caro]

How weird is that. I've just acquired some bangle dies and am currently obsessed with making bangles!

I was just thinking of making an interlocking 3 band bangle myself yesterday and then this thread appears! Mine would be 60mm internal dimensions (wanders off to find calculator).

Thank you mathematical geniuses!

[bruggen]

How weird is that. I've just acquired some bangle dies and am currently obsessed with making bangles!

I was just thinking of making an interlocking 3 band bangle myself yesterday and then this thread appears! Mine would be 60mm internal dimensions (wanders off to find calculator).

Thank you mathematical geniuses!

I have just bought some 2.5mm copper wire, I plan to roll it down to 1.9mm and hope it goes a little oval too, then put the information and advice to the test plus my own theoretical equation to find out how to end up with the final right diameter . by the way what is a bangle die? what does it look like? or did you mean a mandrel?

[Caro]

I have just bought some 2.5mm copper wire, I plan to roll it down to 1.9mm and hope it goes a little oval too, then put the information and advice to the test plus my own theoretical equation to find out how to end up with the final right diameter . by the way what is a bangle die? what does it look like? or did you mean a mandrel?

This is a bangle die. You use it to make fancy shaped bangles

https://www.cooksongold.com/Jewellery-Tools/Bangle-Forming-Press-Die,-10-Fancy-Scallop-Pattern-prcode-999-6876

[Dennis]

Please don't anybody go straight ahead without testing it in copper first. Dennis.

[Caro]

Please don't anybody go straight ahead without testing it in copper first. Dennis.

Haha - yes wise advice. I was going to use some copper wire but sadly I missed the bangle die with my hammer and caught my thumb instead so that's the end of my metalsmithing for a day or two. Who knew thumbs were used so much!

[Ruedeleglise]

Should have gone to Specsavers! Ouch.
David


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[bruggen]

Please don't anybody go straight ahead without testing it in copper first. Dennis.

got my copper so just working out three lengths, and see how it turns out

[Caro]

I had a go.

I used 233mm and got an internal diameter of 70mm using 2mm round copper wire. I wasn't spot on with my measuring but close enough

[bruggen]

I did my calculation at pi x d+3t, where pi is 3.142, d is 65.5 and t is wire thickness of 1.9, that gave me three lengths of wire at 223.7, after making three copper bangles I cut and interlocked them and they were far too big, on that basis I discounted Josef1 calculation of 232.7 and instead took it down to pi multiplied by d+2t that gave me 216.39 and when the copper was done it gave me a triple interlocking band that was 64.5 by 67 oval, I made a silver one using pi d+2t and it came out perfectly, I now have another to make in slightly thicker metal

[bruggen]

I had a go.

I used 233mm and got an internal diameter of 70mm using 2mm round copper wire. I wasn't spot on with my measuring but close enough
I eventually found used 1.9 oval wire at 216.38 and it worked very well, I also now have a bangle die and a ring die 🫣 thanks for that.

[Caro]

I eventually found used 1.9 oval wire at 216.38 and it worked very well, I also now have a bangle die and a ring die �� thanks for that.

How are you getting on with the ring die? I bought one this week. I tried it with a hammer and ended up with a totally mangled ring as it moved between each hammer stroke. I was very unimpressed.

It works beautifully with the hydraulic press

[bruggen]

I’ve not tried it yet, I’m assuming I will have to use quite a thin wire, I will watch out for movement, maybe annealing the wire first will be a must, a hydraulic press would be by far the best way

[josef1]

glad you got it sorted !

[bruggen]

glad you got it sorted !

Thank you very much for your help too, made me think and made me make from copper first, your rendition should have worked, I did cut the copper to size too but after making mine at 10mm shorter and it being too big I realised yours would be too big too

[Ruedeleglise]

How are you getting on with the ring die? I bought one this week. I tried it with a hammer and ended up with a totally mangled ring as it moved between each hammer stroke. I was very unimpressed.

It works beautifully with the hydraulic press

Hi there. I have made anticlastic spinner rings using doming punches successfully but do like the idea of making bangles. Obviously using doming punches can’t work as even the biggest will be too small. Are you really happy with your bangle die? May well take the plunge!
David


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[Caro]

Hi there. I have made anticlastic spinner rings using doming punches successfully but do like the idea of making bangles. Obviously using doming punches can’t work as even the biggest will be too small. Are you really happy with your bangle die? May well take the plunge!
David


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I love my bangle die! This is the type of bangle it produces. For anticlastic though I have to use a stake.

13543

[Ruedeleglise]

I love my bangle die! This is the type of bangle it produces. For anticlastic though I have to use a stake.

13543

Yes they look amazing. But what I was asking about, and I may well have missed the point is, I would like to make as it were a giant version of a spinner ring as a bangle! I guess I am barking up the wrong tree!


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[Caro]

In that case the bangle die would only make the spinner ring for you.

You are also limited to 2mm wide wire if you hammer it. Now I have a press I'm going to try a heavier wire and see what happens