Making a ring mandrel- jewellery tooling

[OldMetallerParticipant @oldmetaller]

Good morning everyone, I have just rashly promised my girlfriend that not only will we get engaged, but also that I will MAKE her a ring!

I have read up on ring-making, and know that I need a ring mandrel. Being a tightwad, I want to make one out of a steel round bar offcut.

My problem is, I need to know what, in degrees, is the taper I need to cut on the bar, given that the ones I have looked at have a working length of 200mm which tapers from 25mm to 10mm?

I know that somebody on here will know how to work this out, sadly my skill with numbers is non-existent.

As a bonus, if somebody could tell me the ID's of the various ring sizes I would be able to groove the mandrel appropriately.

Over to the vast body of knowledge and information that I know to be present on this forum!

Thanks in anticipation,

John.

[OldMetallerParticipant @oldmetaller]

What is the taper?

[Les Jones 1Participant @lesjones1]

Hi John,
If you dig out your maths notes from school from when you were about 13 they should refresh your memory of trigonometry. As the difference in the small and large diameters is 15mm (25 – 15) then the right angle triangle formed between a line perpendicular to the large end that meets the small end will have one side 200mm long and the other 7.5mm long (15/2) . So now you know that the tangent of the angle is 7.5/200 = 0.0375 As you know the tangent you can find the angle from log tables (If they were still used when you wnt to school.) or us a scientific calculator to find the angle. You will find that the angle whose tangent is 0.0375 is 2.15 degrees. This is the angle between the axis and one side. The included angle will be twice this which is 4.3 degrees.

Les.

[JasonBModerator @jasonb]

The included angle is 4.3degrees so either set your topslide over to 2.15degrees or offset the tailstock which would allow you to cut the taper in one long pass, you will need to offset enough to move the tailstock end of the work 7.5mm closer to you, thats if you need to make a full length one.

Edited By JasonB on 19/09/2016 08:29:34

[JohnFParticipant @johnf59703]

John, have a look at the link below for sizes, quite a bit of info. Regards John

**LINK**

[not done it yetParticipant @notdoneityet]

Here is a simple solution to your problem.

All you need is a ring which already fits her finger. Use it as a comparator. You can then make a short guage at any angle you desire, marking it at the point where her current ring fits.

[Chris Evans 6Participant @chrisevans6]

This brings back memories of making rings from 2 shilling coins. I still have the little jig somewhere that has a vee shape milled in it with a shallow angled dovetail cutter. The coin was then held by hand in the vee and gently hammered to roll the outer so that the writing on the coin was readable from inside the ring. Sizes where taken from a ring that fitted the girl. At the correct inner size the hammering stopped the ring put in the lathe and bored to suit ring size the on a mandrel to form the outer. Polished up they looked nice. Early coins with more silver content where used. One girl I made a ring for had big fingers which meant using a half crown coin to get the size.

Good luck with the ring making. Chris.

[KWILParticipant @kwil]

Try this,

**LINK**

[Speedy Builder5Participant @speedybuilder5]

For a one off, use a morse taper. Fingers are tapered, but I never heard of a standard for fingers.
BobH

[KWILParticipant @kwil]

BobH

The are standard sizes for rings, generally L – W, with suitable gauges to test fingers (and knuckels) for size.

[AndyPParticipant @andyp13730]

Congratulations! Some random thoughts:-

A 2 morse taper covers UK ring sizes G to Q roughly so the most common ladies finger sizes.
A plastic cable tie makes a good finger gauge.
If you do make one a gentle taper is easier to work on – you only need one size after all.
Get a good finish on the taper because that will be the finish on the inside of the ring.
Leather or plastic hammers are great for stretching and won't mar the ring material.

The best thing about working with precious metals – if at first you don't succeed just melt it and start again!

Andy

[Neil WyattModerator @neilwyatt]

A fiend of mine went on a 'make your own wedding ring' course. he was very pleased with the result.

Neil

[Neil LickfoldParticipant @neillickfold44316]

If you have a lathe, just make a couple of form tools and turn up the ring to the profile and diameter that you want. I made my wife a Titanium wedding band for our 15th anniversary . I made a form tool for the inner shape and a form tool for the outer shape, parted it off. Then set it onto a mandrel and blended the side that was parted off. To get the size I just asked her to take a ring to the jeweller in town and got the sizing off them. They told her how many mm diameter it was.

Neil

[OldMetallerParticipant @oldmetaller]

Gentlemen, thank you for the wealth of information and ideas you have presented, I knew you wouldn't let me down! Thanks BobH, I'm really pleased to hear that a 2MT mandrel will suffice as I have a couple of these in my 'lathe tooling' box, doing nothing.

Les Jones 1 and Jason B, thank you for the very detailed and specific info, I still don't pretend to understand the maths but at least I know what to do now!

AndyP, I'd better not get the cable ties out, last time I did that she phoned the police!

Once again, thank you all very much.

Regards,

John.

[Sam Longley 1Participant @samlongley1]

Posted by Chris Evans 6 on 19/09/2016 09:42:32:

This brings back memories of making rings from 2 shilling coins. I still have the little jig somewhere that has a vee shape milled in it with a shallow angled dovetail cutter. The coin was then held by hand in the vee and gently hammered to roll the outer so that the writing on the coin was readable from inside the ring. Sizes where taken from a ring that fitted the girl. At the correct inner size the hammering stopped the ring put in the lathe and bored to suit ring size the on a mandrel to form the outer. Polished up they looked nice. Early coins with more silver content where used. One girl I made a ring for had big fingers which meant using a half crown coin to get the size.

Good luck with the ring making. Chris.

How many times did you get engaged you cheep romeo?

Hope you did not marry the one with the big fingers — never bodes well for the future

[Sam Longley 1Participant @samlongley1]

Posted by Neil Wyatt on 19/09/2016 12:51:57:

A fiend of mine went on a 'make your own wedding ring' course. he was very pleased with the result.

Neil

Cannot have been that good — sounds as if he ended up married !!!!!!

Edited By Sam Longley 1 on 20/09/2016 07:37:38

[Chris Evans 6Participant @chrisevans6]

Sam, I married a skinny one from Northern Ireland that I met in Spain. Still together after 44 years.

The rings I made where a bit of a fun thing for a few girls that worked where I served my toolmaking apprenticeship and a few other friends. I did make my wife one but she lost it, hers turned out a bit wide to get down to the skinny size. 5/8" diameter from memory.

[Gary WoodingParticipant @garywooding25363]

With over 55 years experience as a goldsmith I can assure you that there is no standard taper for a ring triblet. Choose anything that's handy and covers the size you need.

In UK, ring sizes are denoted by the letters A (smallest) to Z (largest), with very nearly 1/64" (actually 0.992/64" between one size and the next. Conveniently, size C has an internal diameter of 0.5060", which is near enough 1/2", and size Z is 0.8625" which is near enough 55/64".

You haven't said what materials you will use for the ring – what metal, what stone(s) etc. Your post suggests you will make the engagement ring.

If this is your first ring I would strongly recommend practising before making the real one, especially if you intend setting stones.

Please report back on your progress.

 

Edited By Gary Wooding on 20/09/2016 08:14:52

[davidkParticipant @davidk]

Surely if only making the one ring, you don't need a full length ring triblet, you could use a Stub Mandrel…

[Gary WoodingParticipant @garywooding25363]

Posted by davidk on 20/09/2016 09:08:45:

Surely if only making the one ring, you don't need a full length ring triblet, you could use a Stub Mandrel…

Absolutely! I'm sure Neil would agree.

(I added the dimensions to indicate what sort of precision is required.)

[Sam Longley 1Participant @samlongley1]

Posted by Chris Evans 6 on 20/09/2016 07:43:17:

Sam, I married a skinny one from Northern Ireland that I met in Spain. Still together after 44 years.

The rings I made where a bit of a fun thing for a few girls that worked where I served my toolmaking apprenticeship and a few other friends. I did make my wife one but she lost it, hers turned out a bit wide to get down to the skinny size. 5/8" diameter from memory.

Do they take long to make ??

My wife reminded me this morning- as she went to golf- that I have forgotten out 47Th wedding anniversary ( for about the 45th year in a row) can one make one in the time it takes to play 18 holes , allowing for a few sliced shots & a cup of tea afterwards

[Neil WyattModerator @neilwyatt]

I won't raise to the bait…

[Sam Longley 1Participant @samlongley1]

Posted by Neil Wyatt on 20/09/2016 10:57:06:

I won't raise to the bait…

Clearly a seasoned forumite !!!!

[Another JohnSParticipant @anotherjohns]

I made a ring mandrel for two engagement rings. Got the dimensions from the proposer, who is an engineer and who knew how to measure rings.

The mandrel consisted of 3 turned diameters; one for "hers", one for "his" and one to fit into a drill chuck. Rings made of wood – turned out beautifully, and they "worked" as the wedding was about a month ago.

[VicParticipant @vic]

Posted by AndyP on 19/09/2016 12:14

A 2 morse taper covers UK ring sizes G to Q roughly so the most common ladies finger sizes.

Andy

Is a brilliant idea. Why bother making something you're never likely use again when you probably already have something in the workshop.

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