Putting in electrical pattress boxes

[onomatopoeia]

Did this in my old place by drilling lots of holes and knocking it out with a hammer and chisel and it was a right pain in the bum. Need to do some in the new house for cat5 and would like to find an easier way to make the rectangular holes in the walls. Don't mind spending to get the right tools for the job.

My house was built in the 1950s and seems to be made of grey blocks that I would call "breeze blocks", but there is probably a better word for them that I don't know.

[B17NNS]

http://www.screwfix.com/prods/24725/Drill-Bits/Ele...

An electrician friend of mine bought one.

Used it a few times but went back to stitch drilling and a chisel though.

[Simpo Two]

I used a hammer and chisel but if you don't like that, how about an angle grinder to make the four main cuts to the correct depth, then chisel from there?

[bobr]

SDS Drill in hammer mode and a chisel bit, every spark I have worked for uses them

[RedLeicester]

onomatopoeia said:

Did this in my old place by drilling lots of holes and knocking it out with a hammer and chisel and it was a right pain in the bum. Need to do some in the new house for cat5 and would like to find an easier way to make the rectangular holes in the walls. Don't mind spending to get the right tools for the job.

My house was built in the 1950s and seems to be made of grey blocks that I would call "breeze blocks", but there is probably a better word for them that I don't know.

If the blocks are solid (as a rock, badum tish) then concrete, if they flake a smidge when you run your hands over them then they're early thermalite. The latter can be bashed easily into shape. For the rest, SDS is the way forward.

[Paul Drawmer]

You need an SDS box cutter.

http://www.transtools.co.uk/store/prod_2760/cuttin...

Magic in Thermalite!

[rsv gone!]

Simpo Two said:

I used a hammer and chisel but if you don't like that, how about an angle grinder to make the four main cuts to the correct depth, then chisel from there?

It is how they are cut out on site. Problem is it absolutely fills the place with dust - even with dust control.

[Redmax]

Paul Drawmer said:

You need an SDS box cutter.

http://www.transtools.co.uk/store/prod_2760/cuttin...

Magic in Thermalite!

How does that actually work? Do you still have to chop out the bit in the middle? It can't leave a finished square hole, shirley?

[PaulG40]

rsv gone! said:

Simpo Two said:

I used a hammer and chisel but if you don't like that, how about an angle grinder to make the four main cuts to the correct depth, then chisel from there?

It is how they are cut out on site. Problem is it absolutely fills the place with dust - even with dust control.

Thats how I did my kitchen re-wiring, dust was an issue though but thats what a S10 respirator is good for. If it keeps out Saddam's Biological crap then it'll keep the dust out too, lol.

[garycat]

bobr said:

SDS Drill in hammer mode and a chisel bit, every spark I have worked for uses them

This is what I use for breeze block walls. SDS Drill set on hammer with a 1" chisel bit.

[onomatopoeia]

Cheers for the responses everyone!

[Stegel]

Redmax said:

Paul Drawmer said:

You need an SDS box cutter.

http://www.transtools.co.uk/store/prod_2760/cuttin...

Magic in Thermalite!

How does that actually work? Do you still have to chop out the bit in the middle? It can't leave a finished square hole, shirley?

It's a 2 stage operation - a circular cutter takes out the bulk of the material with the drill in rotary mode, then the square cutter, with the drill in impact only mode, is used to square it up. They work like a knife through butter in Thermalite and soft brick but are not so great in concrete blockwork or hard brick - back to a chisel then!

[hairyben]

Stegel said:

It's a 2 stage operation - a circular cutter takes out the bulk of the material with the drill in rotary mode, then the square cutter, with the drill in impact only mode, is used to square it up. They work like a knife through butter in Thermalite and soft brick but are not so great in concrete blockwork or hard brick - back to a chisel then!

soft brick/ not-so soft mortar or vice versa screws the cutter up too so it catches/ skates and gives you a mess/bigger hole (rather than the perfect box hole you envisaged)

More endorsements for stitch drilling if you want a perfect hole in retro-fit/decorated places or grinder/SDS quick job when on sites.