On Thu, 29 Jul 2010 14:46:06 -0700, Bear wrote:
Sadly it's world war two bunker concrete!

Get yerself a good SDS, then... it'll knock through it reasonably quickly
(ours is about 9" with reinforcing metal in it). It took me about an hour
to do mine, but a fair bit of that was measuring because I knew where I
wanted the hole horizontally on the inside, and where I wanted it
vertically on the outside, and there was bugger-all to use as a reference
(with hindsight it probably would have been quicker to just drill a
reference-point hole *somewhere* in the wall and cement it closed
afterwards).

(if you don't have a big SDS and don't fancy buying one, some of the half-
day rental rates aren't bad - or at least they aren't here)

cheers

Jules