Basic Channel Setting
Channel setting is a common method of setting stones and providing protection from chipping girdles that is more common on prong set stones. In this article I will show the basics of channel setting using common bench tools.
We'll start by looking at some of the tools I'll be using to create the channel and set the stones. First we have the silver ring and the 3 diamond simulants, moving clockwise we have a small assortment of files, a pair of dividers, a Foredom hand piece, polishing discs, a small chasing hammer, and a collection of very sharp gravers and 45º setting burs. As with everything in creating jewelry, there are many ways and many tools that can be used for each process. You may find that your jeweler uses a different set of tools, or even a completley different process. This is normal, and what makes creating fine jewelry more of an art than a mechanical process.
I've already polished and prepared the ring for setting. Before I can set the stones, I need to layout exactly where I want everything to go. I lay the stones in the ring and once they are where I want them, I mark the ring at the centerline of each stone. This ensures that I have each stone perfectly spaced. Next I take the dividers and set them to about twice the height of the table to girdle measurement and scribe a line on both sides of the channel. This allows me to have plenty of metal above the stone girdle for setting. If I am too shallow, there will not be enough metal to set the stones properly, and if they are set to deep they will look like they are sitting in a canyon instead of having the tables flush with the top of the ring.
The next step is to cut the seats for the diamond. I like to use a bur slightly smaller than the diamond and then place it at an angle on the line I just scribed. Then I cut that side of the seat by just pushing into the metal. Once that side is deep enough, I straighten the bur and cut down to the other seat. This gives me a nice path for the diamond to be pushed into the channel through. Once the seats are level on both lines, I stop cutting. The first seat I cut is actually slightly deeper than I really need it to be, but it helps in setting the stone.
After cleaning up the setting again to get rid of the scratches and flash left over from cutting the seats it's time to set the stones. If the seats have been cut properly, this part goes quickly. The diamonds are tilted into the channel just like the setting bur and then they should snap into place with just a little bit of pressure. Once set in place they should be evenly spaced and level with each other.
And now for the fun part, hitting the ring with a hammer. This part can be done with a regular chasing hammer and a steel pin, or an air hammer and pin. I prefer to use the air hammer since it makes short work of the setting process, but you run a greater risk of slipping and hammering directly on a stone which could very easily shatter it. The first hits need to be between the stones to keep them from sliding together as you tighten the setting. I use several passes between each stone to lock them in place side to side. Then I go back and hammer the metal down over the tops of the stones. This locks them in place up and down and keeps them from moving around. The last picture in this row shows you just how much cleanup work is left to do after channel setting.
And here I am using a sharp knife edge graver to clean up and straighten the channel walls to make the channel perfectly straight and leave the same amount of metal covering the stones on each side of the channel. Then I can go in with files and sanding sticks to clean up any tool marks and shape the ring to blend in with the channel. And finally, the finished ring. The channel walls are the same width, nice and straight, and the stones are evenly spaced. One more trip to the polishing wheel and this ring is ready to be handed over to the customer.