dennis@home wrote:

I can do one in about 5 - 10 mins with ordinary chisels in the SDS...
If the wall is hard then I usually use a 20mm flat chisel to cut round
the periphery, and then a 40m flat one to chop out the waste working
first from the middle toward the ends, before levelling the middle
bit. (I have found its quite easy to develop a technique for planing
down the back of the chase with the wider chisel - allowing it to skip
across the surface removing a shaving of brick, rather than cutting deep.

Its a lot easier if you drill the corners first and a couple of holes in
the center so you know when its level.

I find if you sink the periphery cut to the same depth on the chisel
then you have an all around depth indicated. Pencil line or bit of tape
on the chisel shank can help for occasions where the depth is not equal
to some easily identifiable point on the chisel (like the end of the
flat section etc)

--
Cheers,

John.

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