# I need to machine my wedding ring - thoughts please?



## AlfJones (Nov 28, 2011)

Hello all.

My wedding ring has sharp, 90 degree edges on it, which is regularly irritating, and occasionally painful, especially if it catches on something. I have spent years waiting for the edges to round off naturally through wear, but nothing has happened.

The ring was made for me by a colleague and is made of Grade 5 Titanium, which I believe is also called a beta alloy. It seems to be exceptionally strong, and has survived a couple of rather severe hammer blows over the years ( a pity the pink fleshy bits didn't fair so well ).

What I want to do is break the edge of the ring on either side, but I'm *vastly* more nervous about putting the ring in the lathe than I have been about anything else I've ever done before.

All I want to do it put a minute chamfer on either edge - but I'm not sure how to best go about it, seeing as I only get one chance at it. 

I was thinking about using a form tool with a tiny 1/4 round cut in it, but have also considered just using a 45 degree chamfer and just using a emery stick, however, I do want to maintain a good finish.

Any advice from the board on how I go about taking the two most critical cuts I will ever make on the lathe would be most appreciated.


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## hitandmissman (Nov 28, 2011)

Is it possible to just file the sharp edges instead of trying to put in a lathe?


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## compspecial (Nov 28, 2011)

I would put it on a tapered mandrel Alf and just touch it with the aforementioned emery stick
                   Stew


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## 90LX_Notch (Nov 28, 2011)

I would make a quick and dirty expanding collet out of aluminum and use a jeweler's file to break the edge. To make the collet turn the od to match the id of the ring. Center drill it; tap it with a convenient thread; slit along the axis; insert a flat head screw and your done. In the attached photo the head is not flat because it was used in a facing operation. This particular collet was used to face both sides of the cam plate for my Poppin build.


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## Swede (Nov 28, 2011)

Wow - I wouldn't touch it with a turning tool. I'd mount it so that the offending edge is accessible, spin it up, and knock the edge down BY HAND using silicon carbide paper, say 320, then 500, then 800 or higher, in sequence, with a little bit of oil on the paper.

Using a turning tool on it will probably make it worse, and a file is too coarse.

You could always simply lay some abrasive paper on a flat, lay the ring on it, and swirl it about using hand pressure. No lathe required.


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## spuddevans (Nov 28, 2011)

I made an expanding mandrel for working on rings, based it on the design found here :- http://www.cartertools.com/mandrel1.html

I've made a few rings out of titainium, it's tough stuff!! If your file doesnt like it, if you have a diamond file that will do the trick. Then use emery to smooth any file marks, going up the grades until you get the desired finish.


Tim


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## MachineTom (Nov 28, 2011)

First Ti is not steel, it is tough stuff, files will cut it but slowly, for cutters carbide is best, HSS needs to be sharp but Ti will dull them quickly, but well enough for what you need to do. Ti will also work harden real quick, then you have to use carbide.


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## rkepler (Nov 28, 2011)

I would machine a pot chuck or e-collet to grip on the outside diameter and leave a small amout of the ring exposed (as well as the inside, since you're gripping on the outside). At that point it would trivial to round over the inside edge using an inside form tool - since it's a really small radius you should be able to make it just by grinding a notch into a HSS tool with the corner of a bench grinder wheel.


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## precisionmetal (Nov 28, 2011)

The problem with machining TI is "dwell" will kill you -- and it's difficult NOT to dwell if doing this on a manual lathe.

It only takes a second (or a split second) of dwell to work harden TI, and the tool AND the surface finish on the part both go in the crapper almost instantly.

I too would vote for a small expanding mandrel to hold it, and then a few grades of silicon carbide paper/emery to round and polish the edge.


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## flatbelter (Nov 30, 2011)

Yea, I tried machining some Ti once, haven't repeated that mistake. 

Second (or third) on the silicon carbide for edge break.

Dremel tool might be OK if your real steady and have some fine craytex.

Otherwise wrap some SiC paper over a dowl and have at it.


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## rleete (Nov 30, 2011)

I recently designed a fixture to go into an electroforming bath. Because of the chemicals we use, it had to be made with titanium rods. These were tapped on one end (1/4-20), and threaded on the other (1/2-13). because we needed it in a hurry, the lathe guy had to single point the threads on the end. Needless to say, I was not his favorite person around here.


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## kwoodhands (Dec 2, 2011)

AlfJones  said:
			
		

> Hello all.
> 
> My wedding ring has sharp, 90 degree edges on it, which is regularly irritating, and occasionally painful, especially if it catches on something. I have spent years waiting for the edges to round off naturally through wear, but nothing has happened.
> 
> ...


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## Mainer (Dec 4, 2011)

Assuming the ring has a smooth and regular o.d., I'm with rkepler (reply #7). Make a stepped bushing with the larger i.d. suitable to hold the ring, with the bushing slit lengthwise after boring and held in a 3-jaw chuck such that two of the chuck jaws straddle the slit to close it. The inner step can be deep enough to allow the ring to go in completely, since I assume you are wanting to machine the edges of the ring's i.d. If you are particularly worried, paint the ring o.d. with a little shellac just before putting it in the bushing and tightening the chuck, and let it dry before proceeding.

With the compound set at an appropriate angle and a small wicked sharp HSS toolbit, just clip off the sharp inner corner. Sharp HSS does fine on titanium. I don't believe work hardening will be an issue. You'll be making a tiny, ideally single-pass cut. Then, if you want, take some #1200 silicon carbide paper wrapped around a small-diameter softwood dowel and round everything over a bit. You may decide you don't need the extra polishing.

You should be able to pop the ring out of the shellac, if you used some, just by expanding the bushing a bit. If that fails, a soak in denatured alcohol will free it. Turn ring over and repeat for the other side.


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## Springbok (Dec 5, 2011)

go to a decent jewelers.

 ;D

Bob


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## doubletop (Dec 5, 2011)

I'm surprised you are still wearing it while its like that,maybe you aren't. If you've seen a ring fingers with rings deeply embedded and lot of blood after they've got caught up on some sticky out bits (technical term) on aircraft, your ring soon ends up in your pocket. But that's a FOD hazard (you'll have to look that up), so maybe you put it on on a chain round your neck. That idea soon wears off so you end up leaving it at home.
_
(I was going to put a picture here but it was a bit gory)_

It sounds like yours is so much a hazard it would take your finger off given a chance. I can see why you are keen to get it sorted.

http://www.securiteconso.org/notice510.html?id_article=510

Pete


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