Glass and Ceramic Drills
From DT Online
Drilling either Glass or Ceramic is quite possible but these are Hard, Brittle materials and great care needs to be taken. Small diameter bits with Tungsten Carbide Spade Bits can be used to drill ceramic tiles quite easily, but for larger diameters and for drilling glass, diamond drill bits are preferred.
Features and Applications
The key to success is to use a Cordless Power Drill at slow speed (and without any Hammer Action!) and not to try and force the drill through (i.e. take time). Do not try to drill a hole too near the edge (e.g. stay at least 20mm away) and mark the centre with adhesive tape to provide a location for the drill point to stop it slipping around at the start.
Most importantly, ensure there is a constant supply of water as a coolant (hence the recommendation to use a cordless drill). This can be done by building a putty or Plasticine reservoir around the drill bit or preferably, immersing the whole work-piece in a shallow tray of water, ensuring it is well supported with a rubber pad, Ply or MDF for example, underneath it (this is a strongly recommended when drilling glass since the surrounding water prevents cracks propagating, which would shatter the glass). The most critical point is when the drill is about to break through, so ease off pressure and ideally have the work-piece clamped or held in some way such that the drill cannot grab.
Safety Point! Ceramics, and especially Glass, are extremely brittle materials and prone to splintering, shattering or cracking. Do not attempt any drilling operations without hand and eye protection and ensure the workpiece is held firmly. Also, do not use mains electric equipment near water.