"Jules" wrote in message
news
On Fri, 25 Sep 2009 22:43:20 +0000, YAPH wrote:
SDS will do it, but will make a mess on the break-out side. Drilling a
smaller pilot hole and then expanding it to 25mm will be easier and make
less mess.

Or if there's access, drill the pilot and then drill the "last inch" or
so of the hole from the other side.



Thanks for the suggestion. However in this case I have access to one side
only.

Anode.