Barry Smith wrote:

You can also get core bits from about 25mm...

But unless I'm very much mistaken, they won't drill through a cavity
wall :-)

What gave you that idea?

I have drilled through a cavity wall many times with a core bit. If you
go for a 6" long core then it is already engaged on the second leaf long
before it has emerged from the first. Alternatively you drill a 8mm
pilot right through and then drill the core from both sides.



--
Cheers,

John.

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