Tile and Glass Drill Bit (5mm)

A tile is a thin brittle plate, and like any brittle plate it is strongest in the middle and weakest at its edges and corners. Drill close to an edge and the stresses from the bit have very little material to spread into, so the tile cracks, usually straight to the nearest edge and usually across the face where everyone will see it. The same applies to drilling close to a hole that is already there.

So plan the fixing before you plan the hole. Keep well away from tile edges and from grout lines, and where a fixing position is forced, consider moving it to the centre of an adjacent tile instead. If a fixing genuinely must land near an edge, drilling into the grout line itself is sometimes the better answer, though grout holds far less than a plug in solid backing does.

Support matters too. A tile that is well bedded on adhesive is supported across its whole back and will take drilling. A tile with a hollow behind it, which is common on poor tiling and can be found by tapping and listening for a drummy sound, has nothing behind the drill point and will crack. Tap first; it takes seconds.

One thing follows from all this when you choose the fixing. The plug must reach past the tile and into the material behind it, because the tile itself holds almost nothing. A plug sitting mostly within the thickness of the tile and its adhesive bed will pull out and take a piece of tile with it. So drill deep enough to seat the whole plug in the backing, and pick a plug length accordingly rather than using whatever is in the tin.

Five millimetres suits standard wall plugs for bathroom and kitchen fittings, shower screens, mirrors, cabinets and brackets.

Run slow, keep it cool, and never use hammer action.

YG6X cross carbide tip, medium carbon steel shank, 1/4 inch quick release hex shank.

Buyers are tilers, bathroom and kitchen fitters, plumbers, shopfitters, glaziers and hardware shops.

Ask on 94 77 111 8880 about bits, plugs and fixings for tiled walls together. Island-wide delivery.