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Post by parfive on Oct 7, 2023 21:59:07 GMT -5
I don’t do it most of the time but I still like to cut some the way Bear Creek finished his cabs with a continuous curve from the dome all the way around to the back. No bevels, no edges.
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Post by hummingbirdstones on Oct 7, 2023 22:20:52 GMT -5
I don’t do it most of the time but I still like to cut some the way Bear Creek finished his cabs with a continuous curve from the dome all the way around to the back. No bevels, no edges. That's really the only way to cut a cab that's going to be prong set. Having a "straight" bezel with prongs would look not so good.
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rocknewb101
fully equipped rock polisher
Member since October 2022
Posts: 1,368
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Post by rocknewb101 on Oct 9, 2023 7:38:35 GMT -5
This is a fairly simple job - done it hundreds of times. First,this is the shape meant by "no girdle." It means a gently slope from the base, also called a girdle: Use a template closest to the shape of the ring if you have one. Shape your cab, including dome, and test base dimensions against the ring. Trim the base to shape using nothing coarser than a 22o hard wheel, leaving it very slightly on the large side. Finish sanding and test size frequently. Make adjustments as needed. Polish.
If base is still too large it's a simple job to trim a bit more to exact size and repolish.
You may have to trim the prongs slightly and file them to shape, depending on the dome height. A little downward pressure on each prong with a prong pusher after closing them will guarantee a tight fit. Polish prongs and proudly wear your new creation! Interesting!! Ok. this will be a bit of a detour from what I'm used to doing when cabbing, but I see clearly in your pictures what you mean by no girdle. Thank you for this!! This is a fairly simple job - done it hundreds of times. First,this is the shape meant by "no girdle." It means a gently slope from the base, also called a girdle: ...
Just to underline what gemfeller has pointed out — you want a gentle slope that curves gently from the base of your cab to the top of the dome. In other words, after doming your cab, don't cut a girdle (like you see on many/most of the cabs on RTH). Thank you!! This will be interesting to try! The ring looks like a 12x10 mm this is a standard size on many traditional templates. Mark the stone with a pencil then grind to the line. Except grind 1/32 or so outside the line all the way around. (Note*** you did not say type of material.) If soft stone leave more space. You should be just outside the line by the time you get to the 220 grit. grind lightly with the 280 just to clear off the scratches from the previous wheel. Once you get down to 600 you do not have to worry too much about over grinding unless it is a soft stone. finish as normal. before setting flatten back on 280 if needed. put a chamfer or round slightly the sharp edge where the back meets the girdle with the 600 grit wheel. This keeps the prongs from chipping the back if it does not fit 100%. One other thing even standard sizes vary from manufacturer so depending on the template maker and the ring maker there may be some variation. Honestly, I haven't chosen what material I'm going to use yet. I have a chunk of what I believe is Paulina pink limbcast that I was considering, but I'm not 100% sure yet. It'll be a harder material for sure. Thank you for the steps here - this is very helpful! Step 1: glue rough stone into ring. Step 2: throw in tumbler. Step 3: Watch stone magically shape into place. Works 0% of the time, every time. Don’t take that literally 😂 hahaha! Wouldn't that be awesome! All the guesswork gone! I ran into a minor problem with my earlier small dome cabs. It’s easy to leave a sharp edge where the dome and the bottom bevel meet, (girdle?). If the sharp edge bites into the metal of the setting, it can knap a flake from the side of the cab. It takes remarkably little pressure to knock a flake off. It’s worse with bezels than with prongs. It can happen when you’re sizing and pre-fitting the cab too. That’s a nice looking ring. Is it sterling? realrockhound Your post gave me a belly laugh. Oh! Good to know. Thanks for that tip - I'll be careful. I believe it is sterling silver. We'll see how it turns out. Only $11-ish on Etsy, but I didn't want to spend a ton on my first try. I've been cutting cabs for more years than I care to admit. And not until recent years have I run into the confusion over the definition of a stone's girdle. "The Dictionary of Gems and Gemology," written by the founder of the Gemological Institute of America" is old but reliable. It defines the girdle as "The outer edge or periphery of a fashioned stone." That definition holds true for both cabochons and faceted gems. I have a problem with the"new" definition of a girdle as the step cut between he base of the cab (girdle) from the dome. I think it's misleading and incorrect. I also know I'll probably lose the argument, at least in this forum. But it just isn't logical when one deals with both cabs and faceted gems. I didn't realize there was more than one way to define. I can see how maybe the definition might differ between the two. faceting amazes me - I'm not sure how you get all of those facets so neat and uniform. It's a struggle to keep the dome even lol...
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