Laboratory equipment list

They are also quite good on woven/braided rings - again, same thickness all around, no stones. Loren Damewood actually uses them as an integral part of making his bands (at least he did in the workshop I attended - which I highly recommend!).

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Yes, I agree. Our new ring Stretcher/reducer has 8 splines. This will be on our website later this week and is available in US next month.

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Labequipment names and pictures

Hello Amery, It sound as though you are making good use of your ring stretcher. Several small times is better than one large stretch. Check the ring size from both sides to make sure you are stretching it evenly. Don’t try to do it all from one side. Also, if the ring has engraving on the inside, wrap a bit of scotch tape around the stretcher where the ring goes. This will protect the engraving. Have fun.

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I have recently become interested in purchasing a ring size stretcher and reducer. It appears that this may be the best product but was curious to find out if anyone had any actual experience with this tool. I am having a difficult time wrapping my head around the concept of reducing and stretching finished rings. I have not been privy to seeing one of these devices at work nor have I had any first hand experience with them. How many sizes on average can you reduce and increase a ring from it’s original size and does the act of sizing the ring on these devices cause scratches that need to be cleaned up afterward? I plan to use this on a line of rings I am having cast and so there will be the necessary clean-up from the castings anyway but would love if anyone could shed some light on these tools before I spend the $350.

I have also shrunken a number of wedding bands over the years and found it to work very well. Again, the ring must be annealed and one must go slowly. I don’t use it much anymore as I am not doing that kind of work at this time. Now and then but not often. Still, I will never get rid of it!

Stone set rings can be challenging. Any discontinuity in thickness or density becomes a focal point for stress, leading to distortion or breakage when stretching. Stone sets cannot be shrunk (well…I’ve done it but they were etoile style bands and I really really held my breath)

Whereas I now make most of my heavy broad rings a size or so larger than reqd. and shrink them down to size after soldering. Giving me a round ring. With little or no planishing needed.

More often with through with rings with stones to size up small amounts, I opt for my mandrel and planishing hammer because I have pretty good control with hammering up. Sometimes, it is just necessary to either add or remove metal. This depends on the size of the band and the size difference needs to be.

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Ring stretchers are basically only to be used on wedding bands that are the same thickness and width all around. They stretch the band uniformly, if there is a narrow to thick shank or a wide band with cutouts it will stretch at the weakest point and break. They can be used (very carefully and slight strecthing) with other rings but I would not advise it without lots of practice on one.

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Amery, My experience with this stretcher is very similar to yours. On a couple of occasions, when I’ve hesitated to do a job, I’ve had jewelers tell me, “Oh, go ahead and stretch it…it will be alright”. But each time, it was not alright and they had to make it good!! So, Delias, go very carefully into that area. Don’t do rings with stones in them or fancy basket work. Look at the sonstruction…if there are many small connection points I would not take it on.

Be careful with castings. Sometimes they go fine sometimes not so fine. 18K castings in particular have a tendency to just SNAP!

When looking for a ring stretcher/reducer, which is a machine I can’t live without, you should look for a stretcher with more splines rather than less. The splines are what move apart when the handle is pushed up, stretching the ring put on it. A 6 splined model is usually better than a 4 spline model. Sometimes the edges of each individual spline are a bit sharp on the edges, which will tend to leave a series of small cut marks on the inside of the band being stretched.

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A lot of $$ for a tool which does only a very few things well, but when it worked I tended to smile like an idiot. Much fun from a simple tool.

Cynthia says (and she knows) that these only really work on solid rings, they should NOT be used on any rings with stones or baskets, as these areas are the weakest part of the ring (usually) and that is where all of the metal movement is going to take place… NOT a pretty site is you were ever to see it in action. The result is called “remake the ring and, most often, buy new stones”.

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The rings I am interested in stretching are fairly simple but I am wholesaling them so I have been sizing quite a few lately. They are simple in design and made from 10 gauge square wire stock. I had the originals cast and I have been cutting and soldering them to size but with as many orders as I am getting even this is becoming tedious. I currently have them cast in a 8.5 and I could have the set cast in a 6 and stretch them up on my ring mandrel. Stretching them up on the mandrel is incredibly easy because they are so soft when they come back from the casting company. I have been able to stretch them two full ring sizes without annealing. I am trying to decide if I should have them cast again in the size 6 and that would take care of the sizes between 6 and 8 and then I could use the 8.5 castings for larger sizes beyond that. I do offer these rings with stones but I can stretch the stock band and add the stone after stretching which wouldn’t be a problem at all. I am always trying to save time on repetitive tasks if at all possible. Thank you to all for your advice and I have a friend who called yesterday and happens to have the Kagan ring sizer I am considering. She is going to let me come over and try it out. This will help a lot in my decision making. I think it might be a good tool to have either way but in these tight times I am trying to carefully consider costs before assuming any new equipment.

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Decorative Marlingspike Seamanship: Turk's Head Jewelry, tied in gold. I tie knots in precious wire to make jewelry. My favorite knot is the single-line turkshead, or turk's head, which, since it can be either cylindrical or a flattened mat, is well...

Wismar Jewelry is a gallery and goldsmith's studio representing jewelry artist from around the country and jewelry designs by Bill Wismar--a national award winning jeweler and goldsmith. Engagement rings, unique jewelry, platinum, gold, silver, and...

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Yes, yes and yes to all the posts today. Just the ability to shrink a seamless wedding ring down without having to cut it and make it “seamed”, makes it worth having. It can also be used to stretch and shrink “rings” -

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In shrinking, very wide bands tend to cup inside because the force is generally applied at or near the outside edge of the band. If this happens you can try to over shoot the size, then expand on the mandrel but its an iffy thing. How much can you stretch? I’ve gotten up to five sizes on really good bands cut from pipe. More often its limited to one, two, MAYBE three sizes. Sometimes all you can go is a smidge before the ring breaks.

I would buy the most powerful sizer with the greatest travel from top to bottom. I often remove the V wheel and put, say, a doming block or a swage block and have made very small press tools for bending or punching where you need to have great control. Things too small for the swing press.

Making ring bands smaller with the reducer wheel is much easier on solder seams, and less annealing is required. The reducer will tend to leave some small marks on the outside of a band being made smaller, but I’ve found just wrapping a few layers of electrical tape around the outside of the band can help eliminate these marks, if the ring only gets reduced slightly. I have been experimenting with the ring sizer, to see what can be done with it, as a forming tool, as has Andy Cooperman. I plan to make a new instructional video soon showing what a creative tool a ring stretcher/reducer can be.

You can increase your success rate by going easy. Try to muscle a ring and it very well may pop. Finesse the thing along and you’ll get more out of a ring. Stretch a quarter size, loupe the ring, if ok stretch another quarter loupe it and so forth. You’re looking for developing cracks or that funny orange peel look you sometimes get just before the metal is at its limit.

Takes a little work with say, a bit of 400 grit sandpaper, and maybe a rubber abrasive wheel. When stretching up bands, I always have a graduated ring mandrel at hand, and mark the position of the band on the mandrel before I start stretching. I will only stretch a band about 1/4 to 1/2 size before annealing ( stress relieving )and stretching up again. Each time I will mark the ring’s new position on the mandril before putting the ring on the stretcher, so I know how much the ring is moving each time I stretch. If you don’t anneal before stretching, you’ll likely blow out your solder seam, if there is one.

However, I’ve never “shrunk” a ring. I’ve never needed to, and I’m not sure my rings would be the best candidate for this anyway.

If these marks are seen on the band after stretching, you will need to do some handwork, lightly sanding/smoothing down those sharp edges on the splines.

Labequipment names and uses

Sometimes I put one thin ring on top of another then reverse them when the sizes of the Vs are not quite suitable for my needs. Two identical sizes. Or a shim of appropriate thickness can be placed between the platten and the wheel to stop the platten closing completely, as above.

I have two, one is a Kagan which has the mandrel mounted horizontally, the other is a Vigor with the mandrel mounted vertically. Although the Kagan is a better quality tool, I prefer to use the Vigor most of the time, probably because I got used to using a vertical model. The Vigor stretcher is at least twenty years old and is used all the time, and is often treated like the shop’s unwanted stepchild. The rolling mill gets oiled and covered, all the forming tools too, but the poor old stretcher just gets used and abused.

FYI, I was lucky enough to find my Kagan on eBay some years ago at a very good price, maybe $80 or $100. You might get lucky too! I’ve done very well on eBay over the years-- magnetic stirrer $10; Genie lapidary unit $175, etc.

Ring stretchers only really work well with solid or uniform rings, as has been said. Beth is correct, I use them all the time when I’m making rings, though I show people how to get most of the work done without them, if necessary.

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They stretch by expanding the mandrel from inside with a tapered ram. It leaves marks. They shrink by ramming the band into a conical hole. Also leaves marks.

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Like others, I use my stretcher / reducer all the time, couldn’t live without it in fact. I use it for a lot more than just stretching bands though, with a little ingenuity you will find it can be used as a forming tool, a casting straightener-outer, a work hardening tool (which sometimes morphs into a crack finder), a tool for assembling two and three piece bands, as Beth suggested to tighten and straighten woven bands and many other things. The one thing you don’t want to use it for is stretching anything with a solder joint or a fabricated setting, unless you wish to work on your re-fabrication skills and torch control.

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Lab equipment and supplies used in molecular and cell biology labs includes highly specialized instrumentation for data collection and analysis, equipment designed to automate repetitive processes, increase productivity and free up time, and routine laboratory supplies.

A friend told me that his jeweler insisted he buy a new wedding ring because his plain platinum band was a quarter-size too small for him, and the jeweler refused to attempt to change it. I handed him one of my portables and showed him how to do it (a little at a time, as has also been said previously) and within about five minutes he was happily wearing his ring and trying to pay me for my services. He asked me if I had any idea why the other guy wanted him to buy a new ring… silly question. The guy probably needed to make a boat payment or something.

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I use the reducer disc with a hydraulic press instead of with the stretcher. Much more power and control and less marking. I polished the inside of the holes and also use a small zip-lock bag laid on top of the hole to protect the edges and sides of the band being reduced. Works great and no gummy residue to remove. You end up with a whole bunch of plastic circles laying all over the place though. As Jeff says, it’s a surprisingly useful and fun tool that will leave you smiling like an idiot, or crying because you were an idiot to try to use it the way you tried to use it. Think before you stretch!

The lever-action bench model, which I’m guessing is the one that started the discussion, and which includes the reducing press, works much faster than the cheaper portable models I usually use in the workshops, but has exactly the same principle, using a tapered shaft to expand the diameter of the ring mandrel. I highly recommend annealing a ring before attempting to size it up more than a half size or so, but for just a small increase, it’s fine.

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Are you having it shipped or are you picking up? It’s really heavy so I’d pick it up if you can. Also, have them demonstrate. You’re not supposed to just put in on there and stretch. You stretch a little, rotate a little, stretch-rotate, stretch-rotate. Then fllip and repeat. At least that’s how I was taught.

At a shop I worked at, we had a ring roller that was meant for sizing up the shank of the ring and could have stones or design on the front of the ring. It was like the Kagan Ring Roller. We also had the stretcher, but as stated before, this only works well for bands. I found that stretching did not leave a mark, if you were light with the stretch and frequently moved the band. I would be concerned about stretching rings with solder seams from fabricating or previous sizing.

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Makes tension set rings a breeze! Compress, open with stretcher, prepare setting and compress a bit, open ring carefully with reverse action pliers (circlip) and insert stone.

Sometimes I break rings and I learn that I can’t stretch that ring that much or I was doing it too quickly. Different rings definitely stretch differently. If it’s a band that goes wide/thin etc… your weak points are going to be your thin areas, so stretch gently and you’ll have to test it to see how far you can go.

I stretch them all the time. Some of my thinner rings I can stretch a full size as long as they are annealed. Some of my heavier rings are really hard to stretch. And I only go 1/4 size on them.

I have found a ring sizer invaluable, mainly the compression system. Stretching is really only of use for thinnish plain rings, maybe twists and some other applications. Not with stones.