On 10/10/2020 12:40, Dave Plowman (News) wrote:
In article ,
nightjar wrote:
On 09/10/2020 17:17, alan_m wrote:

In the past I've used the angle grinder to chase out electrical back
boxes and have created an amazing amount of dust....

You can buy box sinking tools for use with hammer drills that cut the
hole exactly to the right shape for a single or a double gang wall box.

Seen these and do wonder how well they work.


I've only watched them being used. The chap doing the work was recessing
into HD concrete blocks. It was a two-part job. First, he used a
circular cutter, which looked a bit like the front end of a tunnel
boring machine with a pilot drill in the centre, to cut a hole to the
right depth. The pilot hole provided position for the sinker tool, which
quickly converted the round hole to a square one. It seemed both quick
and effective.

--
Colin Bignell