Drilling pearls...
Drilling pearls...
First I just had to throw this photo of a young boy I met in China who has a lot of practice drilling fresh water pearls. The second photo may be of more interest to you though, as it is a photo of another worker in the same processing plant making a drill bit (especially for fresh water pearls). The drill bits generally used for pearls are a three sided bit (hopefully hardened steel) (see photo 3). They are used because they allow the pearl dust to escape, otherwise it will become trapped, heat up and can ruin the pearl. It is not advisable to start a hole in a pearl using a more common spiral drill bit, although they can be used to enlarge a hole, if need be. I use sizes .7 - 1.2mm, although they can be found smaller and larger. I am not sure about using burs, it sounds like yours are either too fine, or too dull?
Here is the website information for Otto Frei ..
www.ottofrei.com.. a huge jewelry supply dealer. They sell pearl drills, pearl drill bits, and a million other bits for stones and metal.
Photo 4 is of this three sided bit poised to drill a Japan Kasumi pearl. This is my personal drill, I travel with it. It is a wonderful machine. I drill half way into the pearl, and then I am able to spin the vice until it locks in place ensuring that I can drill half way through the other side of the pearl and the holes will meet in the middle.
Photo 5, Here is the contact information for the people we buy both our drills and our drill bits from in Japan. They will ship internationally.
I am not sure if any of this will help with your project, but Good luck!