155mm hole...which drill?

I need to drill a couple of 155mm holes in a wall (Breeze/red brick) with a core drill.

As I only need to drill a few holes I'm thinking of buying a cheap drill for the job (As it's cheaper than hiring it doesn't matter if it gets knackered)

What would be the minimum spec I should look for? Would a bottom of the range SDS drill be up to the job?

Reply to
s--p--o--n--i--x
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I've bought the cheapo (29.99) SDS drill from screwfix - and a box of attachments. Not drilled anything with it yet but used it to remoev an entire room of tiles and to chissle out 20cm of concrete....

I'd be surprised if it wasn't up for the job to be h> I need to drill a couple of 155mm holes in a wall (Breeze/red brick)

Reply to
ryanjjones

Thanks..it doesn't have to last beyond a few holes.

Whilst on the subject does anyone know a good source for core drills, specifically between 152-155mm?

The hire shop want £15 plus £53 wear charge. I can get a new one on ebay for that!

sPoNiX

Reply to
s--p--o--n--i--x

If cost matters but time doesn't, you could drill a series of holes with say a 10mm SDS, then use your chisel option to remove the rest. Easy to make a neat enough job given even a core drill made hole will need sealing afterwards.

Reply to
Dave Plowman (News)

Cost doesn't matter up to a point. What annoys me is that they want to impose a minimum charge that is a rad more than buying a new one. Granted, theirs will be better quality but I'm only drilling two holes!

I'll ponder your suggestion of drilling a series of holes and using a chisel.

Reply to
s--p--o--n--i--x

HSS used to have hire charge plus a cost per mm of wear. Unless you were getting exotic the wear wasn't usually measurable on a brief hire

Reply to
John

Thing is if you're using one of those cheap but powerful drills without a torque limiter, something like drilling a 150mm hole is the most likely thing to tear it out of your hands. A proper core drill has larger handles (and a torque limiter) to minimise the possibility of harm.

For just two holes I'd not bother with a pukka cutter. By the time you got to the hire shop and back, the job would be done.

Reply to
Dave Plowman (News)

It's not fun trying to core drill with a machine that doesn't have variable speed and/or a torque limiter/safety clutch. The £45 Ferm Screwfix have on th eback of the cat (if it's back in stock) is good for this sort of work: the clutch cuts out just before your arm sockets do :-)

Toolstation, or I got a good deal at our local PTS

Reply to
John Stumbles

I have done a couple of 107mm holes using a diamond core in our very hard brick / render wall. Once deep in the hole it close to the clutch torque limit my 780W Makita SDS. In softer material you may get away with a bigger hole and the same amount of power. You could also look at the thinner kerf TCT core drills that screwfix do since these are supposed to require less power (and you don't need the longevity of diamond).

I would not take on a 6" hole unless your drill has a safety clutch and ideally variable speed.

Reply to
John Rumm

save your money and hire the tool,you will not drill 155mm hole with cheap tools,either they or you will burn out

Reply to
Alex

I have found a 780W SDS drill geared to about 1000rpm just on the limit for managing a 100mm diamond core-cut in brick. Don't think it would have managed 155mm. Hiring a 155mm core bit and a suitable drill is big money not counting the worry about the wear charge. If its just a couple of holes suggest getting a SDS drill cheap or better as you wish, a decent 10mm bit and drill round the opening then break out with a chisel. If its a twin leaf wall drill a centre hole through and then each leaf individually. There is a lot of drilling this way, you will find a 2-3kg drill better than the 5-6kg real cheapos unless you are a weightlifter.

Jim A

Reply to
Jim Alexander

I go with this approach.

That and a bit of work with a small chisel to clean up afterwards. and mortar and sealer to sort out any leaks..

Reply to
The Natural Philosopher

My 127 mm cutter binds like hell unless I use the vacuum dust extraction attachement. This keeps the cutter faces and hole clear and the problem goes away. I'd simply hire the whole shebang from a "decent" hire firm for a couple of holes

Reply to
John

There are a couple of problems you can have drilling brick walls with a core drill a) using it on hammer action can knock the bricks out of the wall. b) if the drill binds it will try and twist you.

Reply to
Mark Evans

Yep, this is a problem with TCT drilling but not with a diamond core which must be used without hammer.

I'm sure I remember hiring a TCT bit/Kango combo which did little more than scribe a circle before I got tired holding it up, if I recall.

Indeed, which is why people who have been there advocate getting a drill with a safety clutch. The real cheapos don't seem to feature this, even the Axminster, though at least their brochure cautions about this.

Jim A

Reply to
Jim Alexander

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