On 10/10/2020 09:27, Bob Eager wrote:
On Sat, 10 Oct 2020 06:27:28 +0000, jon wrote:

On Fri, 09 Oct 2020 20:52:26 +0100, Brian Gaff \(Sofa\) wrote:

I don't think this is a new idea though, but the equipment may be.
When back in the 70s we had this house rewired they cut the edges round
using some kind of hammer tool and then just gunged out the middle.
That was a technical term used by the elecctrician.. grin.
Brian


I've done it quite successfully by hand with a cold chisel and hammer.

Easier with an electrician's bolster!



Mark box outline+5mm on wall, put tape on SDS bit for depth required (or
set depth bar on SDS drill), drill many holes to desired depth, use a
scutch chisel and lump hammer to knock-out between holes, and a wide SDS
chisel to "plane" the bottom of the hole flat.