Diamond drill bits are specifically designed for cutting holes in very hard materials such as glass, mirror, tile, stone, porcelain, and ceramics. The extremely hard nature of the materials requires that the diamond drill bits be used with proper drilling techniques. Improper use can overheat and damage the drill bit and may also cause heat fractures and material breakage.
The three primary drilling techniques are Drill Speed, Drill Pressure and Lubrication. These techniques must work together to allow the drill bit to function without overheating from friction due to the extremely hard material. When used properly, the diamond drill bit should NEVER be HOT. The drill bit should never be more than warm to the touch. If a bit becomes hot, it is an indication of inadequate lubrication, too fast a drill speed or too much pressure for the specific material being drilled.
Lubrication Tips: When drilling with diamond bits, the primary concern is merely getting enough water lubrication on the cutting edge of the bit. An excellent lubrication technique is to build a "dam" around the drill hole using a small amount of modeling clay or a similar material. This method can be very effective, especially if the water extends above the side tip lubrication hole to allow water to flow into the bit providing good interior lubrication. "Pumping" the drill is also very important to increase the lubrication at the tip. Without the pumping technique, the water will not reach the very tip of the drill bit. The clay can be used many times if it is stored in a plastic zip-lock style bag to keep it from drying out.