I need to drill a 105 mm diameter hole in a masonry wall 300 mm thick.

It is for the installation of a Miele vented dryer.

All I have is a 750W Bosch SDS Plus drill and some long enough drill bits

What other bits and pieces do I need?

I guess I need one of these:

http://www.screwfix.com/app/sfd/cat/...88072&id=17748

and one of these:

http://www.screwfix.com/app/sfd/cat/...8110&id=14520#


I have a 20mm drill already, can I use it as a pilot drill?

Also, what tips and advice do I need to take into account?

How do you break the core? With a hammer and chisel?

I have never drilled a hole this big. I have drilled the same wall for a 15mm pipe with a normal SDS Plus drill and was easy, but 105mm is new to me.

Thanks,


Antonio

On Sun, 23 Sep 2007 23:59:15 +0100, asalcedo
wrote:


I need to drill a 105 mm diameter hole in a masonry wall 300 mm thick.

Assuming masonry = "House bricks"


It is for the installation of a Miele vented dryer.


All the builders we've had here just smashed their way through with a
cold chisel and a lump hammer. (London Brick Co "Heather" bricks).

DG

asalcedo wrote:

I need to drill a 105 mm diameter hole in a masonry wall 300 mm thick.
It is for the installation of a Miele vented dryer.
All I have is a 750W Bosch SDS Plus drill and some long enough drill
bits

You have few options really.....

Core drill will give you the neatest hole. Alternatively you could chain
drill a ring of holes with a small SDS bit, and then chop out with a SDS
chisel.

I guess I need one of these:
http://tinyurl.com/yvfp9d
and one of these:
http://tinyurl.com/2ckkbt

You may find one cheaper on eBay. Depending on how hard your bricks are
you may need to look at a diamond core rather than a TCT one.

I have a 20mm drill already, can I use it as a pilot drill?

Probably not - the pilot drill usually needs a tapered shank to fit into
the arbour.

Also, what tips and advice do I need to take into account?

Drill a hole right through the wall with a small SDS bit first - that
saves the pilot bit having to cut at the same time which will slow you
down quite a bit. Once you have started the core and have sunk it to a
couple of cm you can remove the pilot drill - you wont need it any more
and it may increase the possibility of snagging.

Take it slow and don't push too hard on the core drill - your 750W drill
is a tad on the small size for this job really (I have cut similar cores
with my 780W SDS - and it only just hacks it since you are right on the
threshold where the clutch will slip).

When starting the whole you can "orbit" the body of the drill a little
such that you cut the core a little wider to start with. Once you are
into the core keep it straight and level.

Be prepared for the drill to snag - the clutch on the machine should let
go before you get your wrist twisted off, but take care just the same -
don't keep anything too delicate in the path of the side or back handles
should they decide to go for a spin!

How do you break the core? With a hammer and chisel?

Stick a SDS chisel in the drill...

If you are cutting through a cavity wall, then chances are you won't
need to - the core bit is usually deep enough to go through a whole brick.



--
Cheers,

John.

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asalcedo wrote:

I need to drill a 105 mm diameter hole in a masonry wall 300 mm thick.
It is for the installation of a Miele vented dryer.
All I have is a 750W Bosch SDS Plus drill and some long enough drill
bits
What other bits and pieces do I need?
I guess I need one of these:
http://tinyurl.com/yvfp9d
and one of these:
http://tinyurl.com/2ckkbt

You can do it much easier (and cheaper) than that.

If you look around you should be able to get a through-wall
fitting kit, which includes a round to square converter to go on
the inside wall, a rectangular duct roughly half a brick in
section, and an external louvred cover.

All you have to do is measure carefully, chop out half a brick on
the outside, use a long masonry drill to mark the 4 corners, then
chop out inside. I didn't even need to make good the plaster,
the interior plate easily covered everything.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

Considering the expense, it might be cheaper to get a specialist
drilling outfit to come and drill it. In my area it's about 25 quid a
hole.

Hello John,

Thank you for your detailed and clear explanations.

I will give it a go with a core drill. A ring of holes looks like too much longer job and less neat, but it is certainly always an option.


One important thing, is it safe to drill a hole this big? This is an outside load bearing wall right at the bottom of the property that is about 9 meters told and built in 1926 with bricks.

Will the wall be weakened at all structurally?

The biggest holes I saw drilled in this wall nearby were 50mm wide.


Many thanks again.


Antonio

asalcedo wrote:

I will give it a go with a core drill. A ring of holes looks like too
much longer job and less neat, but it is certainly always an option.

With a SDS drill and a small bit (say 8mm) you can stick holes through
quite quickly, so I don't expect it would be any slower, just not as
tidy at the edge.

One important thing, is it safe to drill a hole this big? This is an
outside load bearing wall right at the bottom of the property that is
about 9 meters told and built in 1926 with bricks.

Will the wall be weakened at all structurally?

No problem at all - you are only taking out a chuck the size of a brick
or so.

The biggest holes I saw drilled in this wall nearby were 50mm wide.

What about the connection to the soil stack from the loo - that is
probably larger than you are proposing.


--
Cheers,

John.

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Owain wrote:
avocado wrote:
... In my area it's about 25 quid a hole.

Which is very reasonable when you consider what 'working girls' charge...

How much do they charge then? ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Wow, I did not know there are specialistst for that. That sounds indeed like the best idea.

However, I just found one, Drilltec, that quoted me £365 + VAT. Apparently because is half day's work for them, perhaps because of their location.


I am in Central London, would you know one cheaper?

John Rumm wrote:
asalcedo wrote:

I will give it a go with a core drill. A ring of holes looks like too
much longer job and less neat, but it is certainly always an option.

With a SDS drill and a small bit (say 8mm) you can stick holes through
quite quickly, so I don't expect it would be any slower, just not as
tidy at the edge.

Unless you think you'll be making a habit of drilling holes this big, I
wouldn't even consider buying a core drill - they're pretty expensive
and as John says, it's dead easy to do it by chain-drilling. Remember
that the outside face will be covered by some form of grille anyway,
which will hide any slightly ragged edges to the hole.

David

Lobster wrote:

Unless you think you'll be making a habit of drilling holes this big, I
wouldn't even consider buying a core drill - they're pretty expensive
and as John says, it's dead easy to do it by chain-drilling. Remember
that the outside face will be covered by some form of grille anyway,
which will hide any slightly ragged edges to the hole.

I bought a diamond one to do my boiler flue, and anticipated that and
doing an extractor fan would be its only use... in reality I have nearly
worn it out now with all the jobs that come out of the woodwork ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/