I have a hole about 15mm diameter going through about 1m of stone wall.
It's for audio/network wiring and I now need to put through more cables
than will fit.

I'd like to expand the hole and ideally line it with some 32mm waste
pipe. So I need a roughly 35mm hole with a strong preference for it
being exactly along the line of the existing hole.

I've heard that core drills are great for this sort of thing but I've
never used one.

I have a cheap SDS drill. What more do I need? Can the core drill be
guided along the existing hole? Do I buy cheap stuff or hire good stuff?
(I'm unlikely to be doing much like this in future.)

--
Mike Barnes

Mike Barnes wrote:
I have a hole about 15mm diameter going through about 1m of stone wall.
It's for audio/network wiring and I now need to put through more cables
than will fit.

I'd like to expand the hole and ideally line it with some 32mm waste
pipe. So I need a roughly 35mm hole with a strong preference for it
being exactly along the line of the existing hole.

I've heard that core drills are great for this sort of thing but I've
never used one.

I have a cheap SDS drill. What more do I need? Can the core drill be
guided along the existing hole? Do I buy cheap stuff or hire good stuff?
(I'm unlikely to be doing much like this in future.)

shotgun and deer shot has been known..

On Sat, 21 Jan 2012 12:33:36 -0000, Mike Barnes
wrote:

I have a hole about 15mm diameter going through about 1m of stone wall.
It's for audio/network wiring and I now need to put through more cables
than will fit.

I'd like to expand the hole and ideally line it with some 32mm waste
pipe. So I need a roughly 35mm hole with a strong preference for it
being exactly along the line of the existing hole.

I've heard that core drills are great for this sort of thing but I've
never used one.

I have a cheap SDS drill. What more do I need? Can the core drill be
guided along the existing hole? Do I buy cheap stuff or hire good stuff?
(I'm unlikely to be doing much like this in future.)


Is that solid masonry - does it have a random rubble core? Might affect
the answer significantly.

--
Rod

polygonum :
On Sat, 21 Jan 2012 12:33:36 -0000, Mike Barnes
wrote:

I have a hole about 15mm diameter going through about 1m of stone wall.
It's for audio/network wiring and I now need to put through more cables
than will fit.

I'd like to expand the hole and ideally line it with some 32mm waste
pipe. So I need a roughly 35mm hole with a strong preference for it
being exactly along the line of the existing hole.

I've heard that core drills are great for this sort of thing but I've
never used one.

I have a cheap SDS drill. What more do I need? Can the core drill be
guided along the existing hole? Do I buy cheap stuff or hire good stuff?
(I'm unlikely to be doing much like this in future.)


Is that solid masonry - does it have a random rubble core? Might affect
the answer significantly.

Ah. OK. It's not a simple one metre wall, it's two houses built next to
each other with 50 cm walls. I remember some jamming problems when
drilling the original hole so rubble infill is a distinct possibility.

--
Mike Barnes

On 21/01/2012 13:14, polygonum wrote:
On Sat, 21 Jan 2012 12:33:36 -0000, Mike Barnes
wrote:

I have a hole about 15mm diameter going through about 1m of stone wall.
It's for audio/network wiring and I now need to put through more cables
than will fit.

I'd like to expand the hole and ideally line it with some 32mm waste
pipe. So I need a roughly 35mm hole with a strong preference for it
being exactly along the line of the existing hole.

I've heard that core drills are great for this sort of thing but I've
never used one.

I have a cheap SDS drill. What more do I need? Can the core drill be
guided along the existing hole? Do I buy cheap stuff or hire good stuff?
(I'm unlikely to be doing much like this in future.)


Is that solid masonry - does it have a random rubble core? Might affect
the answer significantly.

I cannot see how a core drill will work, though someone may have a good
idea. Core drills require a solid material to drill into as they have a
smallish drill which leads the way thus keeping the core drill steady,
at least that is how the ones I have work.

--
Residing on low ground in North Staffordshire

In article , Moonraker
writes

I cannot see how a core drill will work, though someone may have a good
idea. Core drills require a solid material to drill into as they have a
smallish drill which leads the way thus keeping the core drill steady,
at least that is how the ones I have work.

I think there is some potential for cleverness here, take a dowel of the
same size as the existing hole, drill a hole in the centre of it the
same size as the centre hole of the guide drill, fit dowel over centre
drill and use this as the guide for the core drill. Clear core regularly
and (well tightened) core drill extension shafts will be required.

The dowel doesn't need to be long enough to pass all the way through the
existing hole but it could help in pushing the core drill back out in
case of difficulty.
--
fred
it's a ba-na-na . . . .

fred wrote:
In article , Moonraker
writes

I cannot see how a core drill will work, though someone may have a
good idea. Core drills require a solid material to drill into as
they have a smallish drill which leads the way thus keeping the core
drill steady, at least that is how the ones I have work.

I think there is some potential for cleverness here, take a dowel of
the same size as the existing hole, drill a hole in the centre of it
the same size as the centre hole of the guide drill, fit dowel over
centre drill and use this as the guide for the core drill. Clear core
regularly and (well tightened) core drill extension shafts will be
required.

Cleverness my arse. This is the job for a 32mm masonry bit.

--
Adam

On 21/01/2012 14:45, Moonraker wrote:
On 21/01/2012 13:14, polygonum wrote:
On Sat, 21 Jan 2012 12:33:36 -0000, Mike Barnes
wrote:

I have a hole about 15mm diameter going through about 1m of stone wall.
It's for audio/network wiring and I now need to put through more cables
than will fit.

I'd like to expand the hole and ideally line it with some 32mm waste
pipe. So I need a roughly 35mm hole with a strong preference for it
being exactly along the line of the existing hole.

I've heard that core drills are great for this sort of thing but I've
never used one.

I have a cheap SDS drill. What more do I need? Can the core drill be
guided along the existing hole? Do I buy cheap stuff or hire good stuff?
(I'm unlikely to be doing much like this in future.)


Is that solid masonry - does it have a random rubble core? Might affect
the answer significantly.

I cannot see how a core drill will work, though someone may have a good
idea. Core drills require a solid material to drill into as they have a
smallish drill which leads the way thus keeping the core drill steady,
at least that is how the ones I have work.

You only need the pilot drill to get them started - once you are in
enough to centre the core you can take the pilot out. See the recent
thread on starting cores without a pilot bit.

However the difficulty will be following the existing hole exactly if
not using the pilot. (and often the pilot bit will shake loose from the
arbour if its not actually drilling and just rattling about in an
existing hole - meaning you can't always use it). You might manage by
withdrawing the core often and checking your heading, and drilling in
from both sides.

Personally I thin using a f'off big SDS bit would be easier and quicker.



--
Cheers,

John.

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

On Jan 21, 3:42 pm, John Rumm wrote:

Personally I thin using a f'off big SDS bit would be easier and quicker.

aye.
I acquired a set of 4 X 1m long SDS "hilti" drills for less than £10 a
few years ago - I reckon they are fakes but they are still fine and
have paid for themselves many times over now.

Jim K

In article ,
John Rumm writes:

Personally I thin using a f'off big SDS bit would be easier and quicker.

That's what I did when I needed a hole for a 28mm gas pipe and
sleeve. I hired an SDS-max bit (can't recall if it was 35 or 40mm),
and a thinner one, and drilled through many times starting with a
thin bit, opening the hole out wider each time.

I used my SDS-plus drill with an SDS-max adaptor, but it was probably
a mistake not to hire an SDS-max drill too. If you use an adaptor,
you will probably need one per bit, as you likely won't be able to
get the bits out of the adaptor (hire shop has a tool for separating
them afterwards).

Note all the usual warnings about SDS drills, e.g. they don't stop
just because the bit jams - the drill will spin round and do you a
nasty injury unless you have a tight grip on it and it has a safety
clutch.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

ARWadsworth :
fred wrote:
In article , Moonraker
writes

I cannot see how a core drill will work, though someone may have a
good idea. Core drills require a solid material to drill into as
they have a smallish drill which leads the way thus keeping the core
drill steady, at least that is how the ones I have work.

I think there is some potential for cleverness here, take a dowel of
the same size as the existing hole, drill a hole in the centre of it
the same size as the centre hole of the guide drill, fit dowel over
centre drill and use this as the guide for the core drill. Clear core
regularly and (well tightened) core drill extension shafts will be
required.

Cleverness my arse. This is the job for a 32mm masonry bit.

I've just found this which looks as if it might do the job:

http://www.amazon.co.uk/dp/B000LFYW4...0LFYW4O6217633

(I'm amused by the price clarification "£0.72 / oz". )

I could drill from each end. Hopefully the existing hole will ensure
that the two ends meet. They might not line up well enough to get the
liner all the way through, but if they were close, two 500mm pipes would
be good enough.

--
Mike Barnes

On 21/01/2012 15:42, John Rumm wrote:
On 21/01/2012 14:45, Moonraker wrote:

However the difficulty will be following the existing hole exactly if
not using the pilot. (and often the pilot bit will shake loose from the
arbour if its not actually drilling and just rattling about in an
existing hole - meaning you can't always use it). You might manage by
withdrawing the core often and checking your heading, and drilling in
from both sides.

Personally I thin using a f'off big SDS bit would be easier and quicker.


+1

On Sat, 21 Jan 2012 14:39:45 +0000, Mike Barnes wrote:

Ah. OK. It's not a simple one metre wall, it's two houses built next to
each other with 50 cm walls. I remember some jamming problems when
drilling the original hole so rubble infill is a distinct possibility.

A core drill won't like really loose bits, indeed an SDS drill might
not like loose bits either if a lump drops down into the flutes and
jams. BTDTGTTS...

I can see clearing the core and then threading the the core drill
back into a loose bit 50cm away with no access being "fun".

Think I'd go for the BFO SDS and take it steady, assuming you can get
a 1m long 35mm SDS bit or even 60cm one come to that. At least you
have a 15mm+ pilot hole. B-) I'd also not remove the drill until I
was ready to push the liner through and use that to push the drill
out. Less (note less not no) chance of a bit of rubble fill dropping
down if the drill is there.

--
Cheers
Dave.

Dave Liquorice :
Think I'd go for the BFO SDS and take it steady, assuming you can get
a 1m long 35mm SDS bit or even 60cm one come to that. At least you
have a 15mm+ pilot hole. B-) I'd also not remove the drill until I
was ready to push the liner through and use that to push the drill
out. Less (note less not no) chance of a bit of rubble fill dropping
down if the drill is there.

I'll do exactly that.

Thanks to you and to everyone who responded. I don't know how I'd manage
without this group.

--
Mike Barnes

Dave Liquorice wrote:
On Sat, 21 Jan 2012 14:39:45 +0000, Mike Barnes wrote:

Ah. OK. It's not a simple one metre wall, it's two houses built next
to each other with 50 cm walls. I remember some jamming problems when
drilling the original hole so rubble infill is a distinct
possibility.

A core drill won't like really loose bits, indeed an SDS drill might
not like loose bits either if a lump drops down into the flutes and
jams. BTDTGTTS...

I can see clearing the core and then threading the the core drill
back into a loose bit 50cm away with no access being "fun".

Think I'd go for the BFO SDS and take it steady, assuming you can get
a 1m long 35mm SDS bit or even 60cm one come to that. At least you
have a 15mm+ pilot hole. B-) I'd also not remove the drill until I
was ready to push the liner through and use that to push the drill
out. Less (note less not no) chance of a bit of rubble fill dropping
down if the drill is there.

You still have a good change of hammering a waste pipe though a bit of
rubble drop.

Of course saying such a thing means a very large piece of rubble will fall
into the hole:-)


--
Adam

On 21/01/2012 16:15, Andrew Gabriel wrote:

Note all the usual warnings about SDS drills, e.g. they don't stop
just because the bit jams - the drill will spin round and do you a
nasty injury unless you have a tight grip on it and it has a safety
clutch.


+1
Even if it means hiring it. If the bit jams you *will* be appreciative
of the safety clutch.

Lee

On 22/01/2012 20:22, Lee wrote:
On 21/01/2012 16:15, Andrew Gabriel wrote:

Note all the usual warnings about SDS drills, e.g. they don't stop
just because the bit jams - the drill will spin round and do you a
nasty injury unless you have a tight grip on it and it has a safety
clutch.


+1
Even if it means hiring it. If the bit jams you *will* be appreciative
of the safety clutch.

Indeed. I have never yet had a standard SDS bit jam though (and never
yet *not* had a core bit snag and slip the clutch at least once!)


--
Cheers,

John.

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

In article ,
John Rumm writes:
On 22/01/2012 20:22, Lee wrote:
On 21/01/2012 16:15, Andrew Gabriel wrote:

Note all the usual warnings about SDS drills, e.g. they don't stop
just because the bit jams - the drill will spin round and do you a
nasty injury unless you have a tight grip on it and it has a safety
clutch.


+1
Even if it means hiring it. If the bit jams you *will* be appreciative
of the safety clutch.

Indeed. I have never yet had a standard SDS bit jam though (and never
yet *not* had a core bit snag and slip the clutch at least once!)

I've had an 8mm bit jam, but that just twisted off. Looked like
a sausage of plasticene after someone twisted it in half. More
annoying was that one of the mounting holes for something heavy
was unusable due to 3/4 of the bit being jammed in it.

Had core drills jam too, but mine has a clutch, although that's
only any use if you're holding it firmly.

A friend had two accidents. First was a core drill which jammed,
and the drill spun round, but only a little way before it hit a
wall, and then it put a bend in the [rented] core arbor, making
it useless.

Second time I don't know what he was drilling, but the drill
spun round and whacked him on the chin, which required stiching
in A&E.

I believe twisted wrist injuries are also a possibility. ISTR
someone here having done that in the past.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 23/01/2012 17:27, Andrew Gabriel wrote:
In ,
John writes:
On 22/01/2012 20:22, Lee wrote:
On 21/01/2012 16:15, Andrew Gabriel wrote:

Note all the usual warnings about SDS drills, e.g. they don't stop
just because the bit jams - the drill will spin round and do you a
nasty injury unless you have a tight grip on it and it has a safety
clutch.


+1
Even if it means hiring it. If the bit jams you *will* be appreciative
of the safety clutch.

Indeed. I have never yet had a standard SDS bit jam though (and never
yet *not* had a core bit snag and slip the clutch at least once!)

I've had an 8mm bit jam, but that just twisted off. Looked like
a sausage of plasticene after someone twisted it in half. More
annoying was that one of the mounting holes for something heavy
was unusable due to 3/4 of the bit being jammed in it.

Yup, I can see that being irritating on so many levels!

Had core drills jam too, but mine has a clutch, although that's
only any use if you're holding it firmly.

The clutch on my SDS is relatively tame with a 107mm core. As long as
you are holding both handles it gives without too much twist.

In tricky walls it actually lets go too easily. I have got a Sparky core
drill, but in reality that let's go almost as easily, so it not actually
that much more useful even though in theory it has a few hundred watt
more power. I think one day I will ebay that and get a proper one!

A friend had two accidents. First was a core drill which jammed,
and the drill spun round, but only a little way before it hit a
wall, and then it put a bend in the [rented] core arbor, making
it useless.

Second time I don't know what he was drilling, but the drill
spun round and whacked him on the chin, which required stiching
in A&E.

I believe twisted wrist injuries are also a possibility. ISTR
someone here having done that in the past.

I remember walking through a a multi story car park once and there were
a couple of blokes installing some new fire alarm wiring. They were core
drilling close to the ground - almost sat astride the side handle of the
drill. I thought to myself at the time, if that snags you are going to
be using your nuts as an end stop!


--
Cheers,

John.

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