Using Bezel Blocks and Punches

Q: Q: I’ve got a set of bezel blocks and punches, which are a series of graduated conical holes in a steel plate and the punches that fit them. But when I’ve tried putting a disk of metal in there and pounding, it makes a crumpled, torn mess. What am I doing wrong?

A: Your problem is trying to produce a bezel from a solid flat disk. That will tear just about every time, and it’s not how it’s done. Instead of thinking of bezel blocks as tools that do the whole job of making a bezel or the preform for making a crown head, think of them as forming dies whose main role is to take a preshaped bit of metal and refine that shape into a perfectly uniform one. You just have to start with something closer to the end result than a flat disk. Try starting with a “washer” shape, a disk with a clean, centered, smooth hole in the middle such that the remaining rim is as wide as you wish your bezel to be tall. Making a bezel this way tends to produce one with a thicker upper edge and a thinner base, which is not always what you might wish, but if it is, that’s how to get there. Punching this then drives the center down and stretches it to become the lower edge of the bezel. This is most useful for round bezels, where simple circle or hole punches can quickly make a washer shape, but you can do this with other shapes too. It works best if you don’t need a bezel with much height.

Or, alternatively (and this is how I most frequently use these), make a straight-sided cylindrical bezel, a short, thick walled tube that drops down a bit into the desired hole. Use the punch to flare it to a clean tapered shape. You can even start with a tube shape as wide as your desired bezel will be on top, but then, instead of using the punch to flare it, you can press it down into the appropriate hole. This compresses the base of the bezel, thickening it, while leaving the top edge the same thickness. You get it close to how you want it this way, then clean it up with the punch. You can press it down into the hole with an actual press, with a vise if you hold the whole thing vertically, or with a hammer, using a flat block on top of the bezel to keep things level, then hammering the block down. I most commonly use a small arbor press for this, myself.

Pressing the bezel into the hole compresses the lower edge, slightly thickening it, as it forces the bezel into the tapered opening. The punch is then used to finish it up, forcing the whole thing cleanly into the block. If, when you’re done punching it into the block, the upper edge is not even, you can either file protruding parts back down to the block surface, or put the bezel into the next smaller opening, and use the surface of the block as a reference surface to mark a level line around the bezel to which you file the edge down. That keeps the upper edge true to the taper of the bezel. The lower edge can then be scribed referencing that upper edge, to refine it too if needed. One unique aspect to this method is the way in which it takes the uniform-thickness metal that you started with, and gives you a bezel that’s thicker at the bottom. While this is not always useful, if you’re doing something like sawing and filing that bezel, usually a round or oval one, into the classic “crown” prong setting, then you end up with prongs that are thicker and stronger at the base than at the tips. That can be a quite good thing, as it makes prongs harder to accidentally bend back away from a stone after setting.

To make a coronet setting, which is basically a truncated cone that’s attached by its small end and pierced on the big end to form prongs, cut a piece of flat sheet the thickness you wish for the tips of the prongs. Make sure this is thick enough – if it’s too thin, you’ll have problems. It will get thicker towards the base, which is good for the strength of the prongs. Figure out what length of stock you’d need were you making a straight sided bezel for your stone, then cut a piece that will make either a straight cylindrical bezel shape, or lay it out along an arc that will make a cone shape when joined. Either way, the top edge will form a circle either the right size for your coronet, or slightly larger. Fit and solder the joint very tightly, so you won’t see a solder seam. Use the hardest grade of solder you can control, or better yet, fuse the seam if you’re using a metal where this works well.

Now round it out if it wasn’t already round. It doesn’t need to be exact. Then, starting with a bezel block hole large enough so your shape only sticks up a bit above the top, force it down in with a press of some sort. If you’re careful, you can use a steel block placed on top so the pressure surface is level to the top of the block, and hammer it down, although I much prefer using a press. The result will still mostly be your original cylinder, but the bottom edge will have started to compress to a cone shape. Move on to the next smaller size hole, until you’ve reached one where the cone fully fills the upper circumference of the hole. At each hole, the amount of the piece that has assumed a cone shape to conform with the bezel block will increase. When you’ve gotten to the point where the hole you’re using is the same or slightly smaller than the original size of your blank, you then can true up the whole thing with the punch.

If the blank was slightly larger than the hole you’ve used, the excess metal will have flattened horizontally to a bit of a rim. Rather than this flange being a problem, it’s put to use, because you left yourself some extra height in the blank. Now you can use that rim as a ready-made layout line and file the top of your cone shape right to the corner of that rim, which is now the top edge and perfectly true to the cone shape. Even if your original blank was exactly the right size to fit your final hole in the bezel block so there’s no flange, the top edge is likely to need a little truing up with a file. Just be sure to keep it level. The block will help you see this. Use dividers to mark the desired distance from that top edge down to the bottom edge. No doubt the bottom edge, which has compressed and thickened, will be a little bit off level – maybe quite a bit. But you can use this scribed line to file that bottom edge true to the top. Now you’ve got a perfect truncated cone shape. For a coronet head, you now scribe a second line an appropriate distance from the bottom edge, and using that line, saw off the bottom, forming a shallow cone that will fit up against the remaining larger one for a base. Now you lay out your prongs, and saw and file them to shape. Then saw out the openings in the bottom of the prongs to match. Clean them all up, and pre-polish at least those bottom cutouts, as well as the top surface of that previously sawed-off bottom rim, which you now carefully solder back onto the top part. A bit more clean-up, and you’re done.

You can also sometimes make the initial bezel smaller, so the punch can be used to stretch the bezel into the die, but as often as not, rather than cleanly stretching the whole bezel edge, it tears it, which isn’t so useful. Bezels without much height work best with this. The main downside to using bezel blocks is that as often as not, the actual size and proportions you need is not quite what the block produces. This isn’t so much a problem with round punches or those with even proportions like squares or triangles, but for ovals or rectangles, where you may wish a different length-to-width ratio, the bezel blocks may be not so useful.

In short, there are a number of ways to use these tools. They are not so much great time-savers as they are a means to get the bezels really straight, with uniform angles and proportions. You can start with a fabricated bezel on which you didn’t spend much time, so it’s not quite straight or perfect in proportions, for example, and the bezel block and punch will even it up for you. You can also, if you wish, use them to help true up a wire setting, but there are problems doing so, because with a wire setting, the upper and lower gallery wires need to remain flat and evenly spaced. If you use a bezel block on an entire setting which is out of true, as the metal moves to fit the block, both the flatness of the galleries and the spacing between them, not to mention the details of the prong wires, can all be thrown out of whack. The blocks ARE useful for truing up single wires, like the gallery wires before they’re assembled, but for that, the block is overkill, as you can do it just about as quickly at the bench. Heavy round rings, though, can be trued up and closed at the same time by driving them into a block, but again, this isn’t an essential role for the blocks. The blocks can true up a cone shape (or equivalent versions in non round shapes), as well as helping to true up their top and bottom edges. I find they work best as compression dies, forcing a pre-made shape down into the block rather than trying to stretch one into the block with the punch. Overly thin metal may not work so well, as it buckles rather than compressing. And be sure the metal is well-annealed first.

by Peter W. Rowe M.F.A., G.G.