Hi All,

Im looking for some recommendations for core drills.

I need to drill two holes through brick walls in order
to install two 4" extractor fans. I have a bosch sds plus
drill but havent used core drills with it before.

I guess there are two types diamond and tungsten teeth.
Not sure what make or what accessories are needed.
Its only the two holes so I dont want to spend too much.
Any advice?

Thanks,
Matthew

On Oct 10, 1:52 pm, Matthew wrote:
Hi All,

Im looking for some recommendations for core drills.

I need to drill two holes through brick walls in order
to install two 4" extractor fans. I have a bosch sds plus
drill but havent used core drills with it before.

I guess there are two types diamond and tungsten teeth.
Not sure what make or what accessories are needed.
Its only the two holes so I dont want to spend too much.
Any advice?

Thanks,
Matthew

Hi

For such a big size of hole you should really use a drill with a
clutch - otherwise you risk breaking an arm if the cutter snags. As
you only need to cut two holes, I would suggest that you would be
better off hiring the equipment.

Our local independent hire firm charges about £30 for the drill and £3
for cutters up to 2" and £5 for cutters over 2"

Steve

"Matthew" wrote in message
ups.com...
Hi All,

Im looking for some recommendations for core drills.

I need to drill two holes through brick walls in order
to install two 4" extractor fans. I have a bosch sds plus
drill but havent used core drills with it before.

I guess there are two types diamond and tungsten teeth.
Not sure what make or what accessories are needed.
Its only the two holes so I dont want to spend too much.
Any advice?

A consumer SDS drill is a bit of a compromise for a 4" hole. Bit too fast
for a 4" diamond core and not enough hammer for a tungsten core. I
virtually guarantee the tungsten will do little more than scribe a circle.

For a true one-off stitching a circle with a 10mm or 12mm SDS drill is as
good a way as any. If a clean cut is really important a 4" diamond core
will just about work with a good SDS drill if you can lean into it enough to
make the teeth just bite unless the brick is really hard. Hire if you trust
the hire shop not to charge you for wear.

Jim A

Matthew wrote:

I need to drill two holes through brick walls in order
to install two 4" extractor fans. I have a bosch sds plus
drill but havent used core drills with it before.

The drill will have a clutch which is vital for jobs like this, what it
may lack (depending on model) is power. I have done 4" cores with my
780W drill and it just about manages - you have to take it easy or the
clutch will let go.

I guess there are two types diamond and tungsten teeth.
Not sure what make or what accessories are needed.
Its only the two holes so I dont want to spend too much.
Any advice?

Diamond core bit and a SDS arbour, and a pilot drill for the arbour.
Stick a 8mm hole through the wall first with an ordinary drill, then
follow with the core bit. The pilot drill will centre it in the pre
drilled hole (this save trying to drill using the pilot and no hammer
action!).

If you are doing both holes on the same day then hiring might be more
cost effective. Having said that if you buy it, you will probably find
other uses (and users) come out of the woodwork! So it may keep you in
beer tokens.

--
Cheers,

John.

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On Wed, 10 Oct 2007 05:52:39 -0700, Matthew wrote:

Hi All,

Im looking for some recommendations for core drills.

I need to drill two holes through brick walls in order
to install two 4" extractor fans. I have a bosch sds plus
drill but havent used core drills with it before.

I guess there are two types diamond and tungsten teeth.
Not sure what make or what accessories are needed.
Its only the two holes so I dont want to spend too much.
Any advice?

I have used SDS drills for coring up to 110mm and it's a PITA. The only
SDS machine I had which did have a clutch had it set too low (and it
wasn't adjustable) so the core would get stuck in the hole with the
machine uselessly clacking away on. Funnily enough it was worse with small
cores: the 100mm wasn't too bad. On clutch-less machines you're forever
fighting the kick when it snags. A lower-powered machine is easier to
handle in this respect! None of the SDS-es had variable speed control.

I now have a relatively cheap 'proper' core-drilling machine which is a
pleasure (relatively!) to use. Its variable speed control is particularly
good when starting a hole. The mechanical gearbox gives good low-speed
torque and it has an effective safety clutch. It took me a while to accept
paying over £100 for a single-use machine but it's worth it for the
ease and safety of core-drilling, which I do enough of in my work to
make it worthwhile for me. The machine is also good for drilling large
holes in metal (due to its keyed chuck which grips twist drills firmly)
and for mixing plaster etc with a paddle.

http://www.screwfix.com/app/sfd/cat/pro.jsp?id=70952

--
John Stumbles

Bob the builder / it'll cost 'yer
Bob the builder / loadsa dosh

John Stumbles wrote:

cores: the 100mm wasn't too bad. On clutch-less machines you're forever
fighting the kick when it snags. A lower-powered machine is easier to
handle in this respect! None of the SDS-es had variable speed control.

I had to smile the other day, walking back to the car in a multi-story
car park there were a couple of bods from a specialist diamond drilling
firm, sticking what looked like a deep 2" core into a re-enforced
masonry wall - about 2" off the ground. Your main drill man was knelt
with one knee either side of the drill, and the side handle just poised
to take a side swipe at his gonads on the first snag....

I did not stay to watch!

--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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On Thu, 11 Oct 2007 11:45:36 +0100, John Rumm wrote:

I had to smile the other day, walking back to the car in a multi-story
car park there were a couple of bods from a specialist diamond drilling
firm, sticking what looked like a deep 2" core into a re-enforced
masonry wall - about 2" off the ground. Your main drill man was knelt
with one knee either side of the drill, and the side handle just poised
to take a side swipe at his gonads on the first snag....

Oh yes, I did say to keep all delicate body parts out of the way of the
machine, didn't I? I once got whacked on the cheek (dangerously close to
the eye) by an SDS that snagged. It was only driving a 12mm drill in
brick, too, so I didn't expect it.

--
John Stumbles

I'm less competitive than you