"marvelus" wrote in message
...
On 28 Jun 2006 10:25:50 -0700, " wrote:

. I can't see why you wanted
to pilot the guide bit right through first.

Thats where the arbor goes.

Genuine question; when 'producing' a wide hole through a cavity wall (
plaster, brick, cavity, brick, rendering) should one drill a (narrow) pilot
hole all the way through -then, and only then, widen the hole using the
'big' bit with its 'guide bit' fitted centrally.?

--

Brian