Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

I have attempted to hire a hole cutter but they seem to stop at 6",
which is definitely too small.

The depth and nature of the wall is an additional problem. It is about
12" thick, and is made up of two 4" rows of breeze blocks with an
insulation-filled cavity between them. The breeze blocks are faced with
masonry on the outer wall, and plaster on the inner wall.

Drilling a circle of holes and knocking out the core would, I imagine,
be pretty tricky in terms of lining up the drill holes given the depth
of the wall. It would also be time consuming, and the end result would
be ragged.

Any suggestions for better methods would be welcome - particularly if
someone knows where I might hire a hole cutter big enough to do the
job! (I live near Norwich, just in case anyone knows anwhere local to
me.)

Thanks.

Pete wrote:
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

I have attempted to hire a hole cutter but they seem to stop at 6",
which is definitely too small.

The depth and nature of the wall is an additional problem. It is about
12" thick, and is made up of two 4" rows of breeze blocks with an
insulation-filled cavity between them. The breeze blocks are faced
with masonry on the outer wall, and plaster on the inner wall.

Drilling a circle of holes and knocking out the core would, I imagine,
be pretty tricky in terms of lining up the drill holes given the depth
of the wall. It would also be time consuming, and the end result would
be ragged.

Any suggestions for better methods would be welcome - particularly if
someone knows where I might hire a hole cutter big enough to do the
job! (I live near Norwich, just in case anyone knows anwhere local to
me.)

Thanks.

HSS do a 200mm diamond drilling rig £96/day +VAT

http://www.hss.com/g/1611/Drilling_R...cuum_Pump.html

hth

Pete wrote:
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

I have attempted to hire a hole cutter but they seem to stop at 6",
which is definitely too small.

The depth and nature of the wall is an additional problem. It is about
12" thick, and is made up of two 4" rows of breeze blocks with an
insulation-filled cavity between them. The breeze blocks are faced
with masonry on the outer wall, and plaster on the inner wall.

Drilling a circle of holes and knocking out the core would, I imagine,
be pretty tricky in terms of lining up the drill holes given the depth
of the wall. It would also be time consuming, and the end result would
be ragged.

Any suggestions for better methods would be welcome - particularly if
someone knows where I might hire a hole cutter big enough to do the
job! (I live near Norwich, just in case anyone knows anwhere local to
me.)

Thanks.
http://www.brandontoolhire.co.uk/directory/
--
Sir Benjamin Middlethwaite

Pete wrote in message
oups.com...
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

I have attempted to hire a hole cutter but they seem to stop at 6",
which is definitely too small.

The depth and nature of the wall is an additional problem. It is about
12" thick, and is made up of two 4" rows of breeze blocks with an
insulation-filled cavity between them. The breeze blocks are faced with
masonry

I presume you mean render. Masonry is brick or stonework.

on the outer wall, and plaster on the inner wall.

The type of wall makes this easy rather than hard. Breeze blocks cut like
cheese. If you make a rough hole by whatever method comes to hand you can
clean it up with a carbide burr in a drill until your pipe, flue or whatever
fits through.


Drilling a circle of holes and knocking out the core would, I imagine,
be pretty tricky in terms of lining up the drill holes given the depth
of the wall. It would also be time consuming, and the end result would
be ragged.

You do one layer of blocks first, say the inside one, mark the centre and
drill a pilot hole through the outer layer, go outside and mark your 7.25"
hole around that with a compass or pencil and string and then cut that hole
out from outside. Everything should line up fine but once it's all been
plastered and rendered back round whatever it is your fitting through this
hole it'll look perfect whether the holes were ragged or not.
--
Dave Baker


*** Free account sponsored by SecureIX.com ***
*** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com ***

Pete wrote:
Any suggestions for better methods would be welcome - particularly if
someone knows where I might hire a hole cutter big enough to do the
job! (I live near Norwich, just in case anyone knows anwhere local to
me.)

Thanks.

I certainly would not lay out £90 to hire a tool thats going to be used
once in an hour. :-(

I would cut a square to the diameter of the circumference, fit the pipe?
and the fill the four corners with cement pushed in with a stick till it
was solid packing.

--
Sir Benjamin Middlethwaite

The3rd Earl Of Derby wrote:
Pete wrote:
Any suggestions for better methods would be welcome - particularly if
someone knows where I might hire a hole cutter big enough to do the
job! (I live near Norwich, just in case anyone knows anwhere local to
me.)

Thanks.

I certainly would not lay out £90 to hire a tool thats going to be
used once in an hour. :-(

the OP might.

time is money and if I wanted to avoid buggering about for x hours and I
wanted the job done /quickly/, /neatly/ with /minimum effort/, in 1 hour
leaving the other x hours to do something else I would pay the £96+ vat.

.. wrote:
The3rd Earl Of Derby wrote:
Pete wrote:
Any suggestions for better methods would be welcome - particularly
if someone knows where I might hire a hole cutter big enough to do
the job! (I live near Norwich, just in case anyone knows anwhere
local to me.)

Thanks.

I certainly would not lay out £90 to hire a tool thats going to be
used once in an hour. :-(

the OP might.

time is money and if I wanted to avoid buggering about for x hours
and I wanted the job done /quickly/, /neatly/ with /minimum effort/,
in 1 hour leaving the other x hours to do something else I would pay
the £96+ vat.

Since its breezbloc I suppose a tool could be made from a piece of 1" x 7"
long steel flat bar like this ^-----^ the middle grinded away and a short
steel rod welded to the bar for inserting into the drill chuck.
--
Sir Benjamin Middlethwaite

Thanks for all the suggestions.

£90 for one day's hire of a hole cutter is definitely more than I
would prefer, but I tend to agree with the comment that it would be
worth it to get a fast, easy and neat job. However, I checked with HSS
and they advised that the suggested cutter was for cutting holes in
floors and would not cut a horizontal hole through a wall.

One further complication has arisen - I have now been told that the
outer course of blocks might be concrete, and thus (presumably)
considerably harder to cut than breeze blocks.

Interesting suggestions from The3rd Earl Of Derby and Dave Baker. I
have also received a suggestion that cutting holes 2 or 3 inches in
diameter around the perimeter and grinding down the small pieces of
block left between the holes would be a faster way to go. This method
appeals, but I am not sure what might be the best means to cut away the
pieces of block if the outer blocks are indeed concrete. I guess I
could simply cut out the perimeter of a larger hole than I need so that
the pieces left wouldn't obstruct the pipe I am installing, but I would
prefer to make a neater hole than this if possible.

Does anyone have any opinion on this method, and a suggestion of how
best to cut away the pieces of concrete block left between the small
holes around the perimeter of the large hole?

Thanks.

Pete wrote:
Thanks for all the suggestions.

£90 for one day's hire of a hole cutter is definitely more than I
would prefer, but I tend to agree with the comment that it would be
worth it to get a fast, easy and neat job. However, I checked with HSS
and they advised that the suggested cutter was for cutting holes in
floors and would not cut a horizontal hole through a wall.

such drill rigs are available. I've seen them being used.

google search: horizontal drilling rig 200mm http://snipurl.com/mis4

do a bit of ringing round, you will find one. alternatively, give this lot
a ring / search their site http://www.drillandsaw.org.uk/ someone in
your area will be able to quote you for doing the job.

if the outer wall /is/ concrete your best option /is/ diamond drilling.

Pete wrote:
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?


Having read the suggestions put forward so far, and attempted to make a few
neat holes in brickwork myself, I wonder how much it would cost to get a
bloke in who's got the gear and knows what he's doing? Not in the spirit of
DIY, of course, but when a job could be expensive *and* difficult...

Si

On Mon, 13 Feb 2006 19:46:29 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

Pete wrote:
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?


Based on those plastic drill jigs you get for chain drilling
electrical socket metal back boxes howabout this.

As an exansion of what Dave Baker suggested ..

Drill right through at the centre of the proposed hole with (say) a
10mm dia long bit. Maybe use a square on the hole as you start to
ensure it's a square to the wall as you can get.

Get a lump of 8 x 2 sawn (or similar) and scribe yer 7.25" (or maybe
scribe it at 7" or whatever depending what sort of final fit you need)
and using a pillar drill, drill through yer scribed line a series of
holes the diameter of your long drill bit tip at regular intervals
around the circle. I would leave half the diameter of the drill bit
between the hole to try to stop the holes breaking into each other
till you were ready (especially on the inner layer).

Counter bore the middle and use a long 10mm Fischer plug / screw to
pull it tight to the wall then drill through your gide. You could
possibly slacken the fixing screw and rotate your guide to get inter
spaced holes?

If you didn't want to go right through in one go go half way (mark the
drill shank with red tape) and repeat on the inside.

Revove yer drilling jig and redrill at a slight andgle (from both
directions) to join the holes together. When sufficiently broken away
you could probably use the drill bit like a router and cut the
remaning 'bridges' away till the plug falls out ;-)

Trim up with suitable half round 'universal' rasp ;-)

Look at the two plugs, the pretty neat hole through yer wall and go
down the pub with the 100 quid! (or use it to buy a half decent SDS
drill and a couple of long 10mm bits that you can use on the next job)
;-)

All the best and have fun ..

T i m

T i m wrote:
On Mon, 13 Feb 2006 19:46:29 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

Pete wrote:
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?


Based on those plastic drill jigs you get for chain drilling
electrical socket metal back boxes howabout this.

As an exansion of what Dave Baker suggested ..

Drill right through at the centre of the proposed hole with (say) a
10mm dia long bit. Maybe use a square on the hole as you start to
ensure it's a square to the wall as you can get.

Get a lump of 8 x 2 sawn (or similar) and scribe yer 7.25" (or maybe
scribe it at 7" or whatever depending what sort of final fit you need)
and using a pillar drill, drill through yer scribed line a series of
holes the diameter of your long drill bit tip at regular intervals
around the circle. I would leave half the diameter of the drill bit
between the hole to try to stop the holes breaking into each other
till you were ready (especially on the inner layer).

Counter bore the middle and use a long 10mm Fischer plug / screw to
pull it tight to the wall then drill through your gide. You could
possibly slacken the fixing screw and rotate your guide to get inter
spaced holes?

If you didn't want to go right through in one go go half way (mark the
drill shank with red tape) and repeat on the inside.

Revove yer drilling jig and redrill at a slight andgle (from both
directions) to join the holes together. When sufficiently broken away
you could probably use the drill bit like a router and cut the
remaning 'bridges' away till the plug falls out ;-)

Trim up with suitable half round 'universal' rasp ;-)

Look at the two plugs, the pretty neat hole through yer wall and go
down the pub with the 100 quid! (or use it to buy a half decent SDS
drill and a couple of long 10mm bits that you can use on the next job)
;-)

All the best and have fun ..

T i m

one has to wonder why the diamond tipped core drill was invented and
why drilling rigs were invented and why hundreds of enterprising people
have bought drilling rigs and franchises for drilling concrete )

about the only inexpensive solution for the OP is to scribe a circle on
the outside wall, drill a hole in the middle right through the outer and
inner walls to give a reference, repeat the circle scribe on the inside
and then drill series of holes around the scribed circles until the desired
~185mm hole is achieved.

as for finish, it's only the outermost 2 or 3 mm which has to be perfectly
circular as the render / plaster will do what it's desigend to do: hide the
underlying imperfections from a critical eye which most people don't have.

personally, hire the rig or I'd get someone in. someone who does a job
day in, day out usually produces a better result and there are times when
even the most avid DiYer needs to box a job off by paying someone else
to get the whole project over a time consuming obstacle.

On Mon, 13 Feb 2006 22:56:14 GMT, "." [email protected] wrote:


one has to wonder why the diamond tipped core drill was invented and
why drilling rigs were invented and why hundreds of enterprising people
have bought drilling rigs and franchises for drilling concrete )

To make money? ;-)

about the only inexpensive solution for the OP is to scribe a circle on
the outside wall, drill a hole in the middle right through the outer and
inner walls to give a reference, repeat the circle scribe on the inside
and then drill series of holes around the scribed circles until the desired
~185mm hole is achieved.

Yes, that is less expensive than the additional offcut of 8 x 2 but
then he has to ensure every hole doesn't run off as it starts or break
into an adjacent hole and that each hole is perpendicular to the wall
by eye (rather than having a jig that gives him a feel that he's
drilling in the right direction?


as for finish, it's only the outermost 2 or 3 mm which has to be perfectly
circular as the render / plaster will do what it's desigend to do: hide the
underlying imperfections

Assuming he wan'ts to tidy up the rendered finish?

from a critical eye which most people don't have.

True ;-)

personally, hire the rig or I'd get someone in. someone who does a job
day in, day out usually produces a better result and there are times when
even the most avid DiYer needs to box a job off by paying someone else
to get the whole project over a time consuming obstacle.

I'd see that particular job as a bit of fun ;-)

The challenge would be if the outside was accessed by trying to stand
on a 45 deg roof .. ;-) Thanks goodness for ladders and scaffold
boards ;-)

All the best ...

T i m

T i m wrote:
On Mon, 13 Feb 2006 22:56:14 GMT, "." [email protected] wrote:


one has to wonder why the diamond tipped core drill was invented and
why drilling rigs were invented and why hundreds of enterprising
people have bought drilling rigs and franchises for drilling
concrete )

To make money? ;-)

because people who's time is money want to save time and money ;-)

about the only inexpensive solution for the OP is to scribe a circle
on the outside wall, drill a hole in the middle right through the
outer and inner walls to give a reference, repeat the circle scribe
on the inside and then drill series of holes around the scribed
circles until the desired ~185mm hole is achieved.

Yes, that is less expensive than the additional offcut of 8 x 2 but
then he has to ensure every hole doesn't run off as it starts or break
into an adjacent hole and that each hole is perpendicular to the wall
by eye (rather than having a jig that gives him a feel that he's
drilling in the right direction?

it's only the outer skins that need to be perfik.

as for finish, it's only the outermost 2 or 3 mm which has to be
perfectly circular as the render / plaster will do what it's
desigend to do: hide the underlying imperfections

Assuming he wan'ts to tidy up the rendered finish?

from a critical eye which most people don't have.

True ;-)

very true.

personally, hire the rig or I'd get someone in. someone who does a
job
day in, day out usually produces a better result and there are times
when even the most avid DiYer needs to box a job off by paying
someone else
to get the whole project over a time consuming obstacle.

I'd see that particular job as a bit of fun ;-)

I'd see the hiring of a new bit of kit and boxing the job off in a couple
of hours as both educaional and sensible. I've done far too many
'bit of fun' jobs (which paid well) to be wise enough to pay others
to do em these days. mebbes I'm getting soft :-(

The challenge would be if the outside was accessed by trying to stand
on a 45 deg roof .. ;-) Thanks goodness for ladders and scaffold
boards ;-)

aye, praise alan [pbuh] for my sacred scaffold tower )

All the best ...

T i m

reciprocated :-)

Pete wrote:

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

I have attempted to hire a hole cutter but they seem to stop at 6",
which is definitely too small.

The depth and nature of the wall is an additional problem. It is about
12" thick, and is made up of two 4" rows of breeze blocks with an
insulation-filled cavity between them. The breeze blocks are faced with
masonry on the outer wall, and plaster on the inner wall.

Last time I needed to do something like this I stuck a 10mm hole right
through the wall and used it as a center to mark a suitable circle on
each side. Chain drilled round the edge, and then joined the dots with a
20mm chisel in the SDS. Once the pipe was in place and a bit of mortar
around it looked plenty neat enough.

--
Cheers,

John.

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

In article
T i m wrote:
On Mon, 13 Feb 2006 19:46:29 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

Pete wrote:
Hi.

Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?


Based on those plastic drill jigs you get for chain drilling
electrical socket metal back boxes howabout this.

As an exansion of what Dave Baker suggested ..

Drill right through at the centre of the proposed hole with (say) a
10mm dia long bit. Maybe use a square on the hole as you start to
ensure it's a square to the wall as you can get.

Get a lump of 8 x 2 sawn (or similar) and scribe yer 7.25" (or maybe
scribe it at 7" or whatever depending what sort of final fit you need)
and using a pillar drill, drill through yer scribed line a series of
holes the diameter of your long drill bit tip at regular intervals
around the circle. I would leave half the diameter of the drill bit
between the hole to try to stop the holes breaking into each other
till you were ready (especially on the inner layer).

Counter bore the middle and use a long 10mm Fischer plug / screw to
pull it tight to the wall then drill through your gide. You could
possibly slacken the fixing screw and rotate your guide to get inter
spaced holes?

If you didn't want to go right through in one go go half way (mark the
drill shank with red tape) and repeat on the inside.

Revove yer drilling jig and redrill at a slight andgle (from both
directions) to join the holes together. When sufficiently broken away
you could probably use the drill bit like a router and cut the
remaning 'bridges' away till the plug falls out ;-)

Trim up with suitable half round 'universal' rasp ;-)

Stick a big Rawl bolt fixing in the middle of where the hole should be.
Screw a length of studding into it (or better if you can, get a long
bolt with a smooth shank, and cut the head off) - it should stick out a
few inches further than the length of your masonry bit. Take a piece of
3x2 or similar and drill one end to be a sliding fit on the bolt, the
other to fit the neck of the drill. Cut a slot at the drill end and fit
a couple of screws or bolts either side so you can clamp the drill
firmly. Mount the drill in the wood, and slide it onto the bolt -
wherever you drill will be pretty much the right place :-)



stud or long bolt
fitted to Rawl bolt
anchor drill

| | | |
| | \ /
_____| |___________________________\ /_______
| | | | | |
| | | (|) | | (-) |
| | | | | |
| | | | | |
| | | (\) ------------- (/) |
|_____| |____________________________|| ||________|
| | | | ^
| | | | |
| | \ / |
| | \ / clamping screws
| | ------- or bolts
| | | |
| | | |
================================================== ====================
| |
| |
|---------- radius of hole -----------|

Pete wrote:
Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

If it's just one hole, something like this would do it:

http://tinyurl.com/bpzyw

If you want several holes done at once, use one of these:

http://tinyurl.com/acghx

might also be useful, but warn the neighbours first, and use
plenty of dust sheets to cover furniture, etc.

Chris Bacon wrote:
Pete wrote:
Does anyone know of a good way to cut a 7.25 inch (185 mm) circular
hole through a wall?

If it's just one hole, something like this would do it:

http://tinyurl.com/bpzyw

If you want several holes done at once, use one of these:

http://tinyurl.com/acghx

might also be useful, but warn the neighbours first, and use
plenty of dust sheets to cover furniture, etc.

PMSL I make it six holes on the last one. ;-)
--
Sir Benjamin Middlethwaite

If it's just one hole, something like this would do it:


http://tinyurl.com/bpzyw


If you want several holes done at once, use one of these:


http://tinyurl.com/acghx


Well, I am not quite sure that these recommendations would produce the
neat hole I was hoping for...

Anyway, thanks for all the advice.

I have created the hole today, and all went well. In the end I used a
technique that was a combination of the advice I received. I hired a
core drill (with various diameter bits) and bored a series of
interlinked 2" holes around the perimeter of a 7.25" circle on the
inner wall. I used my own SDS chisel to remove the remaining masonry
around the periphery to leave the desired 7.25" hole.

From inside the house I then drilled an 8 mm hole through the outer
wall from the centre of the 7.25" hole, and scribed a 7.25" circle on
the face of the outer wall using a measured piece of string tied to my
8 mm drill bit.

The inner wall had been a lot tougher than expected - not just a normal
breeze block. When drilling my 8 mm hole I had found that the outer
wall was even harder, and it would have taken a long time to bore seven
2" holes throuth it. I therefore chose to bore a single 6" hole (the
largest diameter borer in the kit) in the centre of the 7.25" scribed
circle on the outer wall, and then used the SDS chisel to remove excess
material.

Things went very well. The holes in both the inner and outer wall
blocks were pretty neat. Not as neat as a bored hole, but not far off.
The gaps left around the pipe will be easily filled.

Again, thanks to everyone who contributed; your advice enabled me to
assemble the right equipment in advance and use a technique that
produced a good result. It didn't take long to do, either.

Cheers.

Pete wrote:
Well, I am not quite sure that these recommendations would produce the
neat hole I was hoping for...

Anyway, thanks for all the advice.

I have created the hole today, and all went well. In the end I used a
technique that was a combination of the advice I received. I hired a
core drill (with various diameter bits) and bored a series of
interlinked 2" holes around the perimeter of a 7.25" circle on the
inner wall. I used my own SDS chisel to remove the remaining masonry
around the periphery to leave the desired 7.25" hole.

From inside the house I then drilled an 8 mm hole through the outer
wall from the centre of the 7.25" hole, and scribed a 7.25" circle on
the face of the outer wall using a measured piece of string tied to my
8 mm drill bit.

The inner wall had been a lot tougher than expected - not just a
normal breeze block. When drilling my 8 mm hole I had found that the
outer wall was even harder, and it would have taken a long time to
bore seven 2" holes throuth it. I therefore chose to bore a single 6"
hole (the largest diameter borer in the kit) in the centre of the
7.25" scribed circle on the outer wall, and then used the SDS chisel
to remove excess material.

Things went very well. The holes in both the inner and outer wall
blocks were pretty neat. Not as neat as a bored hole, but not far off.
The gaps left around the pipe will be easily filled.

Again, thanks to everyone who contributed; your advice enabled me to
assemble the right equipment in advance and use a technique that
produced a good result. It didn't take long to do, either.

Cheers.

Good stuff.

pmsl today when i was in the Asda today...

I was looking for a new sauce pan and me brain started wandering, I picked
up a steel sauce pan which was about 7" and me mind went back to this
thread.
What if I took the handle off this sauce pan, sharpened the rim on the
grinder and drilled a hole in the bottom for the scarret holder
mount...would it work?

Bearing in mind it was a thought just for breezebloc. lol

--
Sir Benjamin Middlethwaite

Pete wrote:
If it's just one hole, something like this would do it:


http://tinyurl.com/bpzyw


If you want several holes done at once, use one of these:


http://tinyurl.com/acghx


Well, I am not quite sure that these recommendations would produce the
neat hole I was hoping for...

Anyway, thanks for all the advice.

I have created the hole today, and all went well. In the end I used a
technique that was a combination of the advice I received. I hired a
core drill (with various diameter bits) and bored a series of
interlinked 2" holes around the perimeter of a 7.25" circle on the
inner wall. I used my own SDS chisel to remove the remaining masonry
around the periphery to leave the desired 7.25" hole.

From inside the house I then drilled an 8 mm hole through the outer
wall from the centre of the 7.25" hole, and scribed a 7.25" circle on
the face of the outer wall using a measured piece of string tied to my
8 mm drill bit.

The inner wall had been a lot tougher than expected - not just a
normal breeze block. When drilling my 8 mm hole I had found that the
outer wall was even harder, and it would have taken a long time to
bore seven 2" holes throuth it. I therefore chose to bore a single 6"
hole (the largest diameter borer in the kit) in the centre of the
7.25" scribed circle on the outer wall, and then used the SDS chisel
to remove excess material.

Things went very well. The holes in both the inner and outer wall
blocks were pretty neat. Not as neat as a bored hole, but not far off.
The gaps left around the pipe will be easily filled.

Again, thanks to everyone who contributed; your advice enabled me to
assemble the right equipment in advance and use a technique that
produced a good result. It didn't take long to do, either.

Cheers.

*marvellous* :-)