Can anyone offer any tips on smoothing prongs after setting stones? I find they always end up sharp-ish and prone to catching on fabric, and I still haven't discovered a good way to remedy this and get a nice smooth finish on them.
Get yourself a set of grain tools and a fion. The grain tools are rods of hardened tool steel with a hemispherical depression in the business end. Select one to suit the prong size, fit it to the handle and rotate it over the prong with a little pressure. This smooths, rounds and burnishes the tip of the prong. The fion is a block of brass with even harder steel hemispheres set in so you can sharpen the grain tools as necessary. Works like a charm, but go easy on the pressure until you get the feel for it. Pushing on the handle with a couple of pounds force is something of the order of 5,000 psi at the business end. Good luck!
Joined: Wed Nov 15, 2006 9:44 pm Posts: 1079 Location: Washington State
In addition to the suggestions already put forward I would suggest getting some cup burs and round off the ends of the prongs before cutting the stone seats. I use a pair of bent nose pliers to press the tips down and have modified the pliers by cutting a lengthwise groove into the plier faces at the tips. If you smooth out that groove in the pliers so that it's round, it will fit well with the pre-rounded prong tips and keep things from slipping during setting. With the prong tips already round all you have to do is go over them lightly with a pumice filled, silicone knife edge wheel and then polish.
If you look at Barbra's link you'll see the author using a chunk of wood to keep the seat cutting bur from "running around" the prong tip. I have a better way of doing this. I use a small chunk of 1/4" thick plastic cutting board, maybe 1/2" wide by 3/4" long, which has a groove cut into it's upper surface and clamped in a bench vise. Lay the prong having it's seat cut down into the groove and cut the seat to the shape and depth needed, turn the setting to the next prong and repeat. The nice thing about this is that the cutting is done with the prong being horizontal, so it's easy to hold your hand piece and see what you're doing with minimal contortions.
Joined: Wed Nov 15, 2006 9:44 pm Posts: 1079 Location: Washington State
Alan's grain tools sound like what are called beading tools in most catalogs in the U.S. They work O.K., but as he says, be careful, particularly with brittle or soft stones.
Oh, that makes sense. I've been meaning to get a set of beading tools, but I don't think I'd be confident trying to shape a prong tip with one. I dunno, maybe...it makes sense that it would work, but yeah, would have to be very careful.
The supplier I have used for grain tools (and lots of other neat stuff) is www.suttontools.co.uk, worth a look. As I and the other respondents have noted, you have to be careful at first. The advice given to me as a young student was to practice on glass stones in silver settings, both cheap enough not to worry in the event of a disaster, but the feel and touch you will develop will enable you to approach any job with confidence.
One point I forgot to mention, try and persuade the customer away from soft or brittle stones in rings. Rings get more hammer than most items of jewellery so brittle or soft stones are going to look very sorry for themselves in very short order.
Yeah, the only soft stone exception I make for rings is opal, and then usually just for friends and family with the warning they should expect it to get damaged over time.
I actually had a small tourmaline get scratched and pitted just from some polishing papers, that surprised me, I would have thought tourmaline could have handled that better.
Polishing papers are usually carborundum, hardness 9 1/2 or so. Tourmaline is about hardness 7 1/2, so it is hardly surprising that polishing paper will scratch tourmaline. Rather than risk the finish on a stone I have a slip of hardwood, 1" by 1/16" by 12" with some chamois leather glued on it, I rub it on the rouge block and it gives a fine finish without damaging the stone. Opals I like to protect by using a bezel setting. Works pretty well.
Great tip, thanks. I was always careful with opals, but I figured the polishing papers were safe for stones about 7 hard and up. Thanks for the info. Knowing that, I can at least be thankful I didn't damage more stones, the potential has obviously been there lol.
Your welcome, this is what I mean when I say that the best way of learning is to watch someone do it, (and ask if there is anything you don't understand.
Yeah, that's not really an option for me unfortunately. Everything I've learned so far has been trial and error with a bit of online research. I'd love to take the course at the local art college, but I just don't have the free time, I'm pretty much nailed to my job and on call all the time. On the plus side, I managed to take my mistake to a local jeweller to get some prongs repaired and a replacement tourmaline, and I had enough scrap gold lying around to trade in for credit to more than cover it. $230 error that almost came out of pocket lol.
Joined: Wed Nov 15, 2006 9:44 pm Posts: 1079 Location: Washington State
Robin, If you can't look over someone's shoulder you might delve into the info archived at Ganoksin http://www.ganoksin.com/ Lots of good info and a forum where you can ask questions. Hint: on any forum where you're asking a question, wait a day or so to get more than one answer. Not that you'd get bad answers, but there are always a variety of ways that different people do things and it's nice to be able to choose those that make sense to you.
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