Lapidary 101 Part 3: Shaping And Polishing A Cabochon

Hey guys, Sean here. If you followed along on my previous tutorials for Lapidary 101, we have talked about cutting a slab of stone from a chunk of rough material and then taking that and cutting out preforms, which are the general shape of our finished cabochon. But today I'm going to show you the cabbing machine, which is actually the way to take this preform and grind it to shape and smooth it out and polish it and really make it the finished product. So this is what we cut yesterday. This is a chunk of Crystal Cola, Malachite, and Gem Silica. It might look a little different than yesterday because I dropped it and broke off a piece. But anyway, it's still going to work. So we'll make it work and it'll look real great. And I'm going to show you this machine and we'll get started. This is my cabbing machine. This is a Diamond Pacific Genie. And it's kind of industry standard. They make one size larger. It's called Titan. It has 8 inch wheels. These are 6 inch wheels. And it is a grinding and polishing machine. So we start on the left. We're going to start on this one. And this is a diamond impregnated metal wheel that really does most of the heavy work. And then we're going to move to this one to really smooth out our shapes, kind of our dome. So if you look at this, I don't know if you can see it. There we go. This is what I did last night. And it has a nice wall around it, which is called the girdle of the stone. And then a dome on top. So that's really what we're going for is a nice smooth shape with a good wall around it in order to set properly in jewelry. So we're going to grind it down on these two. And then with the next four, get increasingly fine polishes out of our stone. And it runs with water. This is a little tray with water. And these are pumps that you put under each wheel as you work on it. So you're never running this dry. The water kind of cools the stone down and also keeps the dust down. So I'll go ahead and start this running, and we'll start grinding this preform away. Okay. Now, before we get going, there are a few things that we need to do to prepare. Oftentimes, people, when they cav, will use what are called dop sticks. And they'll take a stick and use wax, a special kind of wax, and adhere it to the back of the stone. And they'll use that to maneuver the stone on the wheels. I've never tried that, but that's never appealed to me. I enjoy working with my hands. So I just use my hands and get real close. But the wheels aren't going to cut you, but they can kind of wear your skin down a little bit. So what I do is use something called alligator tape. And you just wrap it around. It adheres to itself. And you wrap it around. And it's kind of a way to protect your fingers from some of that. So you just kind of do that. And I do it on my two thumbs and then my first two fingers because those are the only ones I really use. So I'm going to go ahead and wrap my fingers up. And when we do this, we also want to use a mask because, as I've said in the past, some of the dust from some of these stones can be dangerous. And also always use goggles on one of these machines because sometimes pieces of stone can shoot off and fly at you. Okay, guys. So first up with this, you can see it's kind of roughly formed. Sometimes you can get a lot closer on your preformed cut. I sometimes like to kind of improvise on the cabbing machine a little bit. So what I'm going to first do is just kind of smooth out the edges and kind of see what shape we're looking at. Because you have to still leave enough material on the edges to have a good girdle. And so with something like this, how it's kind of thin, I'm going to have to cut off some of that. You definitely lose a lot of material in the cabbing process sometimes. So I'm going to go ahead and just start kind of whittling this down a little bit. And then reevaluate and think of maybe a more geometric shape within that. So let me go ahead and do that. Okay, so as you can see, the first thing I'm working here are the walls. So I'm kind of getting a nice shape around or kind of forming my shape. But also if you've chosen which side you want to be the top, that's always kind of a big decision. But you want to go at the wheel a little bit at an angle so you'll have a girdle that's going to slope slightly in all the way around it. That makes setting it in jewelry a lot easier. But that's kind of the standard for making a cab. You want it to have, I think it's like a 12 degree angle is kind of ideal. So when you're hitting the wheel, just kind of put it at a bit of an angle, just down. And I'm going to go ahead and do my wall on the first wheel. And then move over to the smoothing wheel and go around that wall again. And then while you're still on that smooth wheel, or on the second diamond wheel, you want to go on to the back of the stone and actually put a little 45 degree, like kind of one swipe all the way around, around the bottom of your stone. Because if not, you'll have a really sharp edge here. And that's prone to cracking and chipping. So before you start doming the top, you want to finish your wall. And then go around and put a quick swipe of kind of a 45 degree kind of bevel along the bottom to prevent chipping. I've got my general shape now. And that last bit I did was the bevel on the back that I was talking about, where it's just kind of one quick swipe down just to kind of hit the edge to make it less sharp so it's not going to crack. So now I've got the wall finished. This is the shape we're looking at. And what I'm going to do now is start doming in the top and grinding away the top material. And the way I'm going to do that is holding it, so if this is my top, I'm going to hold that flat against this diamond wheel. And I'm actually going to grind it down until I get the girdle wall the height that I want. So the girdle is just the wall around this. So if you want it to be 3 millimeters, you can grind this down. And looking at it from above, you can kind of see it shrinking as you're working on it. And once you get to that height, just keep moving your stone around. And so what we're going to do is kind of work from the outside in. So we'll set the height of the wall around the whole stone first. And then once we have that, we're going to start kind of smoothing out the edges on top of the stone. And that's where the doming comes into play. So I'm going to go ahead and get to work on that. I just wanted to kind of show you where we are. I kept working on the girdle a little bit and was basically grinding it down to that wall height. And we kind of go into the stone just a little bit. We kind of push it up to start doming the top. But I haven't really started focusing on that yet. But this is where we stand right now. It's got a nice smooth wall around it. And it's going to be a really awesome piece. A lot of these blues and greens are the Prisicola malachite in this really kind of milky silica. But you'll be able to see into the stone a lot. There's almost like a forest in there going on. And once you polish it up, that's all really going to pop. So it's going to be amazing. I'm pretty excited about it. And now I'm going to start actually doming, kind of smoothing off the dome. And I'm just going to be working at the same direction I had been before. But instead of focusing on just staying on this wall, I'm going to try to start going up and down to kind of smooth out the top of this. Now I'll whittle that down a little bit too. You don't want it to be too tall. This is where we stand right now. This is after just the first two wheels. Just the grinding to shape with the two diamond wheels. And you can see it's got a nice kind of even wall all the way around it. The bottom, I don't know if you can see that slight bevel to kind of prevent the chips. And just a good kind of low but clean and smooth dome. So these are just the first two wheels. You kind of do most of your forming on those. Actually, the majority, the vast majority of it. And then we're going to go on to this guy. And this is, it's going to smooth out any kind of just small little unevennesses in the top. You can see how it's not perfectly smooth. But after this one, that should just, it's kind of really going to just smooth it out. And then we'll move on to these guys for the final polishes. And just stay tuned. I'll show you how it looks when we're getting close. We're going to end up on the third wheel. And before I hop over to this side, I always stop and dry this off completely. And look at it in the light and check for scratches on the top. Usually if I have them, they're right on the very top of the dome. Because I'll sometimes tend to neglect that part because I don't want to wear it down too much. But you still really have to go over every part real well. The scratches are caused by mostly the first wheel. And then the second one is really going to smooth that down. But again, you have to go over every part of it with every wheel. So after this third wheel here, if you still have scratches, they're not going to come out on these last ones. So you'll need to go back to the second wheel or just stay on the black third wheel for a little bit longer. Just make sure all the scratches get out before you move on to the final polishers. Okay guys, I'm down to the last two wheels. It's looking really, really nice and taking a great polish. So I'm going to go ahead and finish up and just let you watch. I'm pretty much just doing the same movements on each wheel. I usually start with the girdle and I move across the whole surface of the wheel. And then I do the back little bevel. And then as I'm doing the front, just kind of holding it face against the wheel. And just kind of working it and then moving it to different directions. But kind of working it from one side to another and just kind of rounding it out. And kind of feeling the flow, if you will. So I'm almost done and check it out. Thanks so much for tuning in. Here is our final product. And I'll try to get a better video to put at the end of this of it, maybe in natural light. But I'm really happy with how it turned out. It's a beautiful piece. And we got to see how it went all the way from a big chunk of rough rock down to a slab. Then cut to a preform. And then today we went ahead and put the polish on and cabbed it up. And so next we can set this in jewelry. And I think it will make a really beautiful piece. So thanks for tuning in, guys. And subscribe to the channel. I'll be posting a lot more stuff about lapidary and jewelry making. And painting and other stuff in the future. But thanks so much for watching. See ya. I ain't living broke or five justices Sitting here in my chair They say the view out my window Feels the best but I don't really care Because I can't find it and I don't mind