core drill hole?

[theflyingpig]

Hi all, I'm goign to hire a core drill this weekend to drill a hole in outside wall so I can re-route kitchen sink waste. What size bit do I need for 400 mm waste pipe? I've reserved a 400 mm bit but measureing the pipe last night I see this seems to be the inside diameter of the pipe . . .

And - at what height from the floor should my hole be?

many thanks for any advice

 

[Paul Barker]

kitchen sink waste is 40mm take some pipe into hire shop get one bigger than that.

If you mean soil pipe use 127mm or 5" core.

If sink waste core it is good. If soil waste I would stitch drill a circle and bash middle out with lump hammer and cold chisel in your position.

 

[Jasonb]

400mm thats a big pipe

I think you mean 40mm pipe which is about 44mm outside diameter so a 50mm drill bit will be fine.

Jason

 

[Agile]

400mm, thats a big pipe

Jason

Pigs do fly !!!

 

[IJWS15]

You will need the outside diameter of the pipe (taking a piece with you is a good suggestion) and the thickness of the wall you are drilling through.

With these dimensions hire shop should give you the right bit.

 

[theflyingpig]

thanks all - its 40 mm waste pipe so I've changed reservation at hire shop to 45 mm bit.

I've been a bit nervous about this job for some reason - are core drills easy to use? does the bit need cooling with water ? should I slope the hole ? (wall is two bricks thick)

 

[dynomo]

thanks all - its 40 mm waste pipe so I've changed reservation at hire shop to 45 mm bit.

I've been a bit nervous about this job for some reason - are core drills easy to use? does the bit need cooling with water ? should I slope the hole ? (wall is two bricks thick)

Dont be so nervous!!! The drill will be easy to use as long as you remain steady and be very patient as it may take a little while for you to bore through both walls. Trust me, once done, you'll be a satisfied individual!!!

Oh and yes, slope the drill slightly downwards when drilling and you don't need water..

 

[gasandoilman]

Use a good drill with a cluch or you may spin round with the drill
or break your wrist

I have a hilti drill

Hire a drill too

 

[markplumb]

thanks all - its 40 mm waste pipe so I've changed reservation at hire shop to 45 mm bit.

I've been a bit nervous about this job for some reason - are core drills easy to use? does the bit need cooling with water ? should I slope the hole ? (wall is two bricks thick)

as jasonb has already suggested a 50mm corebit will be closer to what you need - 99% of the time there will be an elbow/rodding tee on the pipe within the hole you've just drilled, that's if you want the pipe to run tidily at clip distance. measure the outside diameter of the socket on the elbow + add some.

i use 50mm core for 40mm pipes, 40mm core for 32mm pipes (solvent type)

 

[Balenza]

I would use a large 30mm sds max bit, then the core.
The large pilot hole lets the larger diameter core bit gouge through fast and effortlessly and no stuffing up inside the core.
Works well on cores up to about 60mm.
If break out on a fine render or brick is a possibility then a 10 mm pilot straight through , then drill inwards from each side with the larger bits !.

 

[timmy74]

i detest core drilling the time ot takes and the bloody hole never seems straight ammer and chisel rules

 

[Dan Robinson]

Patience young padawan, feel the core flow through....


Unless they're engineers bricks..

 

[timmy74]

Patience young padawan, feel the core flow through....


Unless they're engineers bricks..

oh yes another 2-3 hour job

 

[Paul Barker]

Core drilling is a pita often would have been better to stitch drill and hammer.

But kitchen waste holes are just asking to be cored.

 

[theflyingpig]

well guys - thanks for all advice . . .
I got stuck straight into it on Friday morning - started the hole on the inside , got through the plaster and breeze block like it was butter . . but then damn pilot drill fell into the cavity between breeze block and brick! oops! tried to keep going without a pilot but after 20 mins of grinding away without a pilot I'd gone 5mm into the brick! luckily found a masonary bit I had kicking around that fitted the hole in core bit - a super long one - so went through brick from the inside then attacked it from the outside - by this point I think the core drill was blunt so had to put it on hammer to get through. . . .the guy in the hire shop had suggested I use hammer action!
so, got there in the end, hire shop didn't charge me for lost pilot or blunt core bit and gave me 20% of drill hire back for getting it back the same day

all in all not too bad, though I'm not exactly looking for opportuniteis to do it again . .