On Tue, 05 Jun 2007 06:02:21 -0700, Thomarse
wrote:

I know you can buy guides from B&Q etc that you place on the wall and
drill a series of holes which you then knock out, but I wonder if
anyone has any experience of using these and whether they are any
good?

They were great for use with hammer drills.

These days, with SDS drills, there's no need. Make yourself a crude
stencil just for marking out (or use a wall box) and then just chisel
freehand to the line. With the vastly improved chiselling power of SDS,
you can freehand it through anything up to concrete with hard aggregate.

You will of course have an SDS drill with a rotation stop, and a
suitable set of chisels, including a plaster-chasing spoon. Foolish not
to.

The back can be rough as anything, just focus on getting the sides
fairly neat.