On 2006-07-23 11:37:19 +0100, Bolted said:

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

This gives the range. I guess you mean their stock code 97416 as an example?




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.

Thanks very much for the offer, unfortunately I'm not though.

I am going to be doing two additional bathroom jobs over the next
couple of years, so amortising the cost and it's not that bad.


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.

I have a drill press, so was thinking that a water bath would be a way
to do the job. Certainly this seems a better approach than
attempting the job in situ.

Thanks for all your thoughts