Bert Coules wrote:
I have to cut a 6" diameter hole through both sides of a cavity wall.
to fit an extractor fan. Before I go and hire a core drill, what's
the possibility of drilling a large number of closely-spaced small
holes and then attacking the wall - first inside, then out - with a
large hammer and a masonry chisel?


I'd be inclined to drill 1 hole dead in the centre of the circle, right
through both leaves. Then you can measure off 3" right round the centre and
drill the holes - alternatively, use a 6" cardboard circle, fixed at where
the hole was drilled. That way you'll guarantee that both holes will meet in
the same place. Hammer and masonary chisel too! I'd think that a 6" core
drill is probably going to have a *LOT* of torque, and could be difficult to
hold, especially if you're up a ladder...

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