Expanding a hole

[Scion]

What's the easiest/neatest way to expand a hole through brickwork due to waste pipe size being increased from 22mm to 30mm? I don't have access to core drills.

[Nthkentman]

What's the easiest/neatest way to expand a hole through brickwork due to waste pipe size being increased from 22mm to 30mm? I don't have access to core drills.

Local scaff company, 3' length of tube and a lump hammer.

Mind ya knuckles

[newshound]

If you have an SDS drill, there are cheap Chinese sets of three drills ~

500 mm long, the largest being about 25 mm nominally. But drive one of these through and then wiggle it about a a bit (with the power on) and you should be able to enlarge it relatively neatly. Core drill no good without a suitable pilot to guide it.

Depending on the wall materials and structure, the time saved over "manual" opening with hammer and chisel would justify buying a cheap SDS (IMHO)

[John Rumm]

Not always the case... stick a similar sized hole in an off cut of ply or similar, then hold/fix that against the wall and use it as a guide to get the core bit started.

No pilot needed ;-)

[Phil L]

An old flat screwdriver and chip small bits off - you only need 4mm on each side and the chances are there's that much clearance already and it'll just be be filler/plaster that needs removing inside. Outside may need a good five minutes work though, although if it ends up

40mm, I don't think a man on a flying horse would notice a 5mm bead of silicone or mortar around it.

[Phil L]

Scaffolding poles are 50mm, and taking one to (probably) newish brickwork would create a hole about 200mm once it's smashed bricks above, below and on each side

[Bill Wright]

Don't you mean a blind man on a gallopin' 'oss?

Bill

[newshound]

Good point (all my walls are rubble fill random stone, not quick to fix a guide board). But I still think in this case I would use a conventional drill.

[John Rumm]

If you use a resonable sized scrap of wood, you can hold it in place with your foot - you only need get the core a couple of mm into the surface to be self guiding.

Yup for that size you could probably find a wide enough SDS bit.

[brass monkey]

Smashed AND removed.

[Andrew Gabriel]

I have hired the odd SDS drill bit up to 40mm diameter (that was to put a 28mm copper pipe plus 38mm plastic sleeve though a wall). It only cost about a fiver for a day, including an SDS max to SDS plus adapter, but that was about 12 years ago. (Note that you probably won't be able to get an SDS max bit out of the adapter, so you'll need one adapter per bit. The hire shop has a special tool to extract them on return. Alternatively, hire an SDS max drill to go with the bit.)

When using an SDS drill with either an SDS bit of this size or a core drill, make sure your drill has a safety clutch. A friend ended up in A&E after doing something similar with a cheap no-clutch drill, which spun and whacked him on the chin, and when it spun a bit further and jammed against another wall, it then wound up the steel arbor like a plasticene sausage, and as it was borrowed from a builder, he had to go and buy a new one to replace it.

[Scion]

newshound spake thus:

I do have an SDS drill, I'll give that a go.