Glass Drill Bit
In order to drill glass, sea glass, wine bottles, glass block, ceramic tile, stone, granite and marble you need to follow these genral guidelines:
1. Use diamond bits to drill your glass, not carbide bits.
2. Use diamond hole saws to drill holes 1/4″ and larger or to drill holes in thick glass like glass block or wine bottles.
3. Use plenty of lubrication/coolant to keep your drill tip cool and the hole clean.
4. Use less pressure! Let your drill bit drill at it’s own pace.
5. Start diamond hole saws at 600-900 RPM.
6. Start diamond drill bits at 2500-5000 RPM.
Everyone has questions about glass drill bits. Some general questions and answers are listed below.
What type of drill bit do I use for different materials?
Use diamond bits to drill hard, brittle materials like glass, ceramics and tile. Drill small holes using a round ball shaped bit. Drill holes 1/4″ and larger using a diamond core bit.
How fast should I drill?
Start slowly and gradually increase the speed. Start hole saws at about 700-800 RPM. Start round end bits at 2500-5000 RPM. The larger your bit is, the slower you should start.
Drilling faster increases friction, burns up the bit. If your drill bit develops yellow, brown, blue or black burn marks around the tip, slow down.
How hard should I press?
Increasing the pressure on twist drills makes the bit drill faster. Not such a good idea with diamond bits. When you use diamond drill bits it is very important to use light to moderate pressure and to let the bit “drill at its own speed”.
Increasing the drill pressure will only increase the friction and heat. This not only burns up the bit, but heat will also fracture or crack the material you’re drilling.
If you are dilling a hole completely through an object, it is important to ease up on the pressure when the drill bit is about to break through. This reduces chipping on the backside of the object when the bit emerges from the back. Better yet drill half way through, flip the material over, start a new hole on the backside and let them meet in the middle.
Should I use lubrication?
Be careful about using any electrically powered tool near water. Water or another lubricant should be used to cool and lubricate the tip of diamond bits. Lubrication reduces heat build-up. Water is usually used.
Increase the amount of lubrication used with harder materials. When drilling in glass, ceramics, or stone use enough water so that the “dust” from the hole is a very wet paste or wetter. The tip of the drill bit should always be wet. If you are drilling hard or abrasive material, use even more lubrication. If you can, have a small amount of lubricant constantly running over the drill tip and bore hole.
How do I start a hole?
Use a drill press or at least use a template to keep the glass drill bit from walking when you’re starting a hole. A template can be made from a piece of wood or plastic. Place the template on the material being drilled, with the pilot hole above your target spot. This will keep the diamond bit centered in place while you start the hole with your hand drill or rotary tool.
How long will the glass drill bit last?
It all depends upon the hardness and abrasiveness of the material being drilled, the tool speed, the pressure used and the amount and type of lubrication. Even materials that appear similar have varying degrees of hardness and abrasiveness. It is impossible to estimate the life of a diamond bit. On some thin, soft materials a diamond bit may last for 50-100 holes or more, while on some thick, very hard or very abrasive materials the life many be only 1-3 holes or less.
Final tips for using glass drill bits:
Do not use diamond bits with impact type hammer drills. The impact will bend the tips.
Diamond bits are not recommended for steel or other ferrous metals. You will get much better results using carbide bits on iron, steel and other ferrous alloys.