Hole cutters - backboxes

tomstickland

I use an angle grinder to cut the edges and then hammer and chisel.

Coolhandluke

Just chisel the block wall out using a Kango hammer , dont need to be to accurate , then mix up some bonding , slap it in to what you have just chisled out and then bed in your back boxes and conduit , bit more bonding on top and then some finish plaster.Job done.

shammyjack

Easiest and quickest way on hard brick or block is a decent SDS on chisel action or a Rotary Hammer combined with a Scutch Tool Holder and Scutch Comb Bit .

On Breeze or Thermalite my 25 year old Impex Wall Chaser will chase out a full 4 bedroomed detached house in a morning , chases and boxes included and will bury a 25mm conduit below the wall face in a self retaining angled chase if required !

shammy

tomstickland

Whilst I'm off topic, a friend of a friend had a contract to fit all the doors and locks on a new estate and found that an electric chainsaw cut exactly the right size hole for the mortice locks to fit into. Great idea.

happyhero

shammyjack wrote:

Easiest and quickest way on hard brick or block is a decent SDS on chisel action or a Rotary Hammer combined with a Scutch Tool Holder and Scutch Comb Bit .

On Breeze or Thermalite my 25 year old Impex Wall Chaser will chase out a full 4 bedroomed detached house in a morning , chases and boxes included and will bury a 25mm conduit below the wall face in a self retaining angled chase if required !

shammy

What are scutch combs meant for exactly? Are they for channeling, if so are they much different to ordinary chisels? They seem to sell them in muliples, is it because they wear out quickly or something?

beer2006

Just like to add my pennys worth.

I don't have to chisel out that many backboxes, but when I do its alot, so I got the screwfix square back box cutter, although i didn't get the rotary cutter, figuring I shouldn't need it.

TBH, even using a big drill several times in the centre, it was a complete waste of time and I wished I'd not wasted my money, used it for 2 holes, went back to using a chisel drill straight away.

Maybe it would have been better with the rotary cutter, but I doubt it, even using the box cut out twice had started to dent the cutting edge.

I'll just add, because some people seem to have used the screwfix cutter with no problems, it was in the harder internal breeze blocks that I did my cutting. Don't know the technical name for them.

shammyjack

happyhero wrote:

What are scutch combs meant for exactly? Are they for channeling, if so are they much different to ordinary chisels? They seem to sell them in muliples, is it because they wear out quickly or something?

I think they were developed as a Masons tool for fine stone working but they are vey hard and it is much simpler to change a worn out bit or comb than resharpen a chisel .

A comb will last for about 6 hours chasing in brickwork depending on the hardness of the brick. It is also much easier to work with as it bites in and holds a tight line without slipping or breaking up the surrounding material .

shammy

mercurystar999

So you didn't get the circular cutter, beer2006? I can't see how the square bit would work on its own as it only takes the edges off the circle usually? You first use the circular cutter and then the square one on hammer stop to square the edges off.

beer2006

Well I tried it with a inch drill, if I can remember, a few times in the middle, so there was only the outside left really.
It was only an experiment to see if they saved any time, or if they worked, if I had been happy with it and it was a pain to use a smaller drill instead of the rotary cutter, I would have got one.
But as it turned out, to me, it was more trouble than it was worth and everyone else I've spoken to on site seems to think the same. Never seen a sparky use one.