"Dave D" wrote in message
om...
Hullo again.
I have to drill a hole in my exterior wall for my combi flue, (its
sandstone)
I believe I need one of these big cake cutter type drill bits, what
are they called ? Do I need a special drill or is my little 850w house
drill up to the job ?
Is this the kind of thing I can hire ?
Cheers

For a one of job like this, you'll be better going to a hire shop and
getting the right gear for a day. Shop about and get some quotes before
making your final decision. The drill bit you need is called a core cutter
and the drill machine itself needs to be able to handle one of these big
babies, so you can imagine the power it has to have. Hiring one is the
easiest way.

Have a look at the boiler manufacturers requirements for the flue size
you'll need and then make the choice of the size of core cutter you'll need
to do the job. You'll probably be charged for the amount of millimetres you
wear down the cutter, but it is sandstone your cutting through so it
shouldn't wear down that much. It's a small amount to pay for getting the
whole job done in one go.

Good Luck with it. :-))