To add a new faucet you may need to enlarge the access hole in a marble countertop. The sleek, natural appearance of a marble counter enhances the look of a bathroom, kitchen, bar or laundry area. Larger holes may be needed in the counter for installing various faucets or electrical cords. Enlarging a hole in the counter is accomplished with a special diamond drill bit. This particular type of drill bit moves through the marble like a wood drill bit drills through wood.
What to use to increase faucet hole size in porcelain sink? - kbarieru.info Forums
The hard nature of porcelain makes it difficult to drill. This difficulty increases when you need to enlarge an existing hole in a porcelain sink. Attempting to drill the hole larger can cause the drill bit to wander, or in some cases, cause it to break. Given the expense of the drill bit required to drill porcelain, it is best to avoid damaging them. Instead, using another tool allows you to widen a porcelain sink's hole without using a drill bit.