Andy Hall wrote:
Hole saw - presuming you are using porcelain you need a diamond one.
The Armeg screwfix ones work fine, or there are cheaper chinese
non-guided versions around.


I guess you mean the diamond core drills?

If you prefer to call it that. A carbide holesaw will do ordinary
ceramic and is much cheaper
http://www.screwfix.com/app/sfd/cat/...50272&id=10322.

For porcelain or stone you'll need diamond, like these

http://www.screwfix.com/app/sfd/cat/...01250&ts=50362

Pricey for a one-off job, though, and I couldn't find anywhere that
rents them. If you are in London-ish I could do them for you if you
bring the tiles round.

These are much much cheaper:

http://www.richontools.com/catalog/c36_p2.html

But they don't have a guide, so you need to improvise something like a
piece of mdf with a hole the size of the outer diameter of the bit to
keep it on track at the start of the cut. For a one-off job, that's
probably the way to go.

You need to keep all of these diamond thingys wet and cool. I did them
in a water bath under my pillar drill, which worked fantastically well
and got loads of wear of the bits (wore one bit out, but it must have
done 50 or so holes in some bloody tough porcelain). If you do it after
tiling rather than before you have to keep spraying the wall/floor
around the cut and it is difficult by doing that to keep the temp down
below the level at which the diamond substrate melts and the drill stops
working for good.