"Andy Dingley" wrote in message
...
On 6 Sep, 23:48, Tim S wrote:
Just checked the FAQ but would like to double check:

I need to drill an 8mm or so hole in a glazed ceramic floor tile (bog
screws).

Two drill bits, ideally two drills (esp. if you're

Mark out with masking tape, well rubbed down, and personally I like to
try a manual centrepunch first by pressing (not hitting) a carbide
scriber point through. There's little risk of cracking a tile, but
there's still some and this increases if the tiles are poorly
supported beneath. Much depends on your individual tiles - some have
really hard glazes that increase the risk of skidding.

Start out with a "leaf" bit, usually sold for glass (Axminster) Start
out gently and don't worry about cracking, worry about sideways
skidding instead. DO NOT HAMMER. For that reason I prefer to use two
drills for this, plain drill for the leaf and SDS for the masonry bit.
This also saves me swapping chucks, but mostly it's to avoid finger
trouble when switching one drill in and out of hammer mode.

Use the leaf to go through the surface porcelain glaze, out to the
full diameter of the hole. Usually you can get right through the back
full diameter too. This hole should be oversize on the final fitting,
so that there's no contact between the bolt or screw and the tile.

That bit about the hole being oversize is really important, especially if
you then use a plug in the hole. If you do the plug should be inserted
*past* the tile or it will exert sideways force as it expands.

Then switch drills to your SDS and a simple SDS hammer bit for
drilling the wall itself. Drill centrally, without thumping the tile.


Personally I've never had any problem drilling tiles. No hammer, no push,
very slow drill, relax.