On Tue, 01 Sep 2009 14:21:32 +0000, pete wrote:
We've got an old house which has walls 5 - 6 feet thick.
What are the chances of drilling through from both sidea and meeting
in the middle?

It depends on the size of the hole you want to create, I suppose.

I drilled from both sides through our basement wall last year - with some
careful measuring (and drilling) the initial 1/2" pilot holes from both
sides were about 1/8" off in the middle.

Of course if a longer bit were available I would have used it, but
that sort of error seems acceptable for most things that get run through
solid walls (I was ultimately making a 6" diameter hole for some
heating duct, so that error was no issue at all)

cheers

Jules