Drilling a 50mm core hole in stone wall

[mikesdiy]

I need to drill a 50mm hole for a waste pipe through a traditional built stone wall about 75cm (2.5feet)wide.

I have never done this before and am gathering together what I think is needed; dont want to start and then find I have not got the required kit!

I have got a 5kg SDS drill (Power Performance) which I think should just be enough for a one time job. I have got a 50mm core cutter with pilot drill incorperated. So far so good that should get me through the first 10-20cm; then comes the problem, I need an extender to get through the 2.5feet.

Been down to my DIY store and have seen the SDS extenders BUT when I look as to how it assembles there does not seem to be any provision for a pilot drill, the core cutter seems to just seems to sit on the end of the extender, is this correct?

Any advice on doing this would be appreciated; my concern is that last time I put a small hole through with a very long 20mm bit I had a terrible difficulty with the bit sticking. Is it going to be any easier with a core cutter?

 

[joe-90]

Most extension pieces are like a bar with a thread on the end and you simply screw the core cutter onto it.

What you really need is a very deep core cutter otherwise you won't be able to get much depth at a time.

If you've only got a little one (ooer missus) you'll have to stop every few minutes and knock of the core with a very long cold-chisel.

Actually the very first thing to do is to drill a pilot hole right through the wall then use the core cutter from each side until it meets in the middle.

It's gonna be a bit of a fiddle but it can be done.


joe

 

[mikesdiy]

Thanks Joe, the meathod you propose (ie a pilot hole all the way through and then use the cutter from both side) is how I sort of envisaged doing the job until I started looking into available kit.

The difficulty unless I am missing something is a) the very long drills that would go all the way through the wall are significantly wider that the pilot drill bit which means the pilot drill on the cutter would just slop about in the hole (perhaps this does not matter?) b) The cutter with the pilot bit will not screw onto the extender, the SDS attaching sprigot is intregral with the cutter; to get a cutter that will screw onto the extender does not seem to have a provision for a pilot bit!

Once you have started the core do you need to have a pilot bit there, or can you just rely on the existing core cut to guide the ongoing cut? I dont feel very comfortable about this as it seems like a recipe to both get stuck and go off track!

Appreciate advice from anybody who has done this. - Mike

 

[Thermo]

First of all you need to start the hole of with a normal core drill bit taht has the pilot hole in it and let it go in until the core drill has started to cut. Then use the one with the extender using the groove already cut to guide it.

One bit of advice. I suspect the drill you have will not have a clutch on it. That means that when the sds bit hits something it doesnt like, the drill will spin around. Now your arm will be attached to it, so they have a tendency to whip your arm around. Ive known people to break a wrist doing it, or get clumped in the face as you lean over the drill and it flies around and smacks you in the face (ive done this one!) If you do use the drill hold it firmly but dont grip it as you normally would. Hold it so that if it bites it will come out of your hand and not do the damage if that makes sense.

If you are really worried, hire out the cutters and the drill for a day, it will cost peanuts. I think in this instance i would as you are going through stone and you do not know what you will hit. Take the drill and the cutters back and get a refund and it will pay for the hire!

 

[seaangler]

beware when hiring diamond cores , not only do you have to pay for the hire but quite often there is a charge per mm of diamond used. If it is a natural stone wall its likely to be soft and abrasive so will wear the diamond down very quickly.
The pilots on a diamond core tend to be about 11-13mm , its fairly easy to buy a metre long 10mm sds bit to use as a pilot (bosch do one which you should be able to pick up for less than £16 plus vat) so you can follow the suggestion of drilling from both sides
Most sds drills do have a clutch , but the clutch tends to kick in a bit late so watch your step !! Withdraw the bit frequently to remove buildup of dust as thats the main reason for the bit jamming

Good luck

 

[RobinClay]

So - erm - nearly five years later.... have you come out the other side yet ?

How did it go ?

 

[merlin50]

as he only made 8 posts i think he has long gone