Water and carbide are not a good mix. The water tends to shock cool the bits and that tends to crack the carbide. If you can keep the water on consistantly its not a problem, but if the bit warms up and gets cooled it will shatter the tip.
Try a glass cutting drill bit. Porcelain is closer to glass than it is ceramic in terms of it's drilling properties. The bits are fairly inexpensive, and you will eat them up as well, but they may work better depending on the type of porcelain.
[This message has been edited by Joule-E (edited 08-31-2002).]
