While drilling holes using the diamond drill bits the most heat generated needs to be cooled off and that is best done by water or a coolant. This lubrication helps in making the life of the drill bit longer as well as prevents the bit from being damaged during the drilling operation.
Lubrication can extend the life of the drill bit quite a bit if the lubrication is done whenever drilling holes. While drilling into glass or tiles the drill bit tip should never be hot and it should be almost warm. This lubrication can help drain away the burr from the drilling process. Another important thing is that the drill bit should be always wet when drilling is happening. While drilling holes into concrete it is advisable to drill in water or have a water pipe or a shower of water over the drilling area as concrete drilling generates a lot of heat.
There a variety of techniques which can be used to lubricate the drill bit while drilling. The most basic method is to use a water hose which will supply water onto the top of the hole as well as the water will get into the hole. Another thing mostly for home users is to have a small water bottle, make a hole at the bottom of it and then keep it near where the hole is being drilled. The water will come out of the bottle and will reach the drill bit as well as inside the hole.
Another technique most widely used to keep the material being drilled into a pan or a plastic cub filled with water. Make sure that water is enough to cover the surface being drilled. Place a small plastic board beneath surface being drilled so that you do not accidentally drill into the pan.
Last but not the least, the best way to make sure that the water as reached inside the hole also, is to do drill using a pumping action. Pumping action action means that you merely drill half an inch each time and then take the drill out , water will go into the hole , then again take the drill into the hole and drill a little bit and then again take the drill out. This repetitive action is called pumping action and it makes sure that the water goes inside the hole and lubricates the bit.