I belong to several groups dedicated to lapidary and the making of rock jewelry and there are some amazingly talented people when it comes to wire wrapping stones to create pendants and earrings. An alternative technique to creating such jewelry relies on drilling the stone. While in many ways simpler, this can produce some pretty neat stuff.
Here's a beautiful piece of local agate on grey basalt that I made into a pendant- simple but nice.
I started by shaping and finishing the stone but you will notice that I didn't go for a high gloss finish because I find the lines and shapes show better if I take it to just this stage without using any polishing compound.
I often have people write or come to the shop asking how to drill rocks- often after they have tried unsuccessfully to do it themselves. So here's how it is done. First, you need the right drill bit.
This is a 1 mm. diamond drill bit made by Drilax. It's true length is 4.5 cm. and I buy them in boxes of 30 at a web site called Wish. They will break (hence the box of 30!) but I like them because on a relative basis they are cheap and the thicker shaft makes it easier to set the bit perfectly vertical in your drill. And speaking of drills, while I know of people who drill rocks with a Dremel, I can't. It is vital that you eliminate as much bit "chatter" as possible because when the bit is wobbly, it creates much more heat and heat is a big problem! So my suggestion is to use a drill press. Going back to heat for a moment, it is important (mostly for the stone) that the operation stay as cool as possible since too much heat can cause the rock to shatter. Some people drip water on the bit, I do it totally underwater. Here's my set-up.
Sorry for the wrong bit- I was doing some wood working and was too lazy to change it. This is a plastic container with a piece of quarter inch wood at the bottom. It is there to stop the bit from putting a hole in the plastic since when I am drilling, the plastic container is filled with water to cover the stone. I will drill stones up to a cm. thick but regardless of the thickness or type of rock, I have found that even using all the patience I can muster, I have a tendency to blow out the back of the stone when the bit exits the finished hole.
To solve this, here's what I do. First, I decide where I want the hole. It should be centered relative to the geometric mass center for the piece. If it is an abstract piece, you may have to hold it lightly to see how it will hang because believe me, gravity always wins! You don't want the hole right on the edge to minimize the chance of fracture but you want it close enough so you can attach your bale and leave room for the chain. Start the hole on one side and drill about 75% of the way through. Then, take the stone out and use calipers to see where the exit point will be. Mark it with a water resistant pen and restart the drilling on that side at that point so the holes meet in the middle. Throughout the process, the stone has to be held absolutely still. Some prefer to clamp the stone using a C-clamp but I prefer to hold it by hand. Drilling should be done slowly with the bit being partly removed from time to time to let water get to the area of the stone where the bit is working.
And that's all there is to it!
Then, when the stone is cool and dry, I attach the bale. In this case it was a 925 silver antiqued bale with two prongs. I buy them and all my other wire and findings from Fire Mountain and if you can put together an order of 100 pieces or more with some friends, you can get some really decent prices (about 60% of the unit price).
The glue I use is FPC Surebonder 9000. It comes in a clear plastic tube and there is no mixing required. I use it to bond all kinds of metal to rocks and have never had one give way, even when I am gluing bell caps. Fill the hole with glue using a thin wire to get the glue in the hole and then warm up the silver bale in your hand. This is necessary to make it a bit more pliable because you then need to open it up to go over the stone and get the prongs on both sides into the hole. Then you have to pinch the bale back together, put some kind of weight on it and let it cure for 24 hours. Make sure that there is no excess glue that can be seen on the bale or stone.
In the case of the above piece, I added a sterling silver 16 inch chain and now it's ready to go in the shop.
If you have questions or want to learn more, just make a comment on the blog or send me an email.