Core drilling.

[ban-all-sheds]

I need to make 2 150mm holes in a 9" brick wall, I've got a reasonably pokey corded SDS so I thought I'd buy a core drill for it. (Yes, I will check first that it has a safety clutch).

Couple of questions:

1) Does the team think that a TCT jobbie will do it? I can't see me ever wanting to do any more so I don't mind if it can only do the 2, but I will mind if it only does 1½.

2) Presumably the procedure is drill the pilot hole, cut to the depth of the core drill, chisel out the "plug", then cut again, repeating until through?

 

[2929twin]

Save the pain from the drinking arm, hire a diamond core set up. Easy through half brick at a time and no hammer!

 

[noseall]

We stitch drill holes as there is usually a cowl, casing or cover that will deal with untidy edge.

 

[ban-all-sheds]

Stitch drilling would be too much aggro - can't be rsed.

I've not looked at the relative costs of buying vs hiring, TCT vs diamond etc - just wanted to know if there's any point, i.e. is diamond the only thing that will actually do the job?

 

[noseall]

There are good diamond tipped cutting tools and there are poor diamond tipped fellas.

It was using a poor one that led me to stitch drilling!

So, as for buying or hiring then i would say that if you are tempted into buying a cheap diamond bit then you may be disappointed and end up with a pig'.

The above said, you would be foolish to buy cheap tat and bonkers to buy an expensive fella for limited use.

So hire a good-un and be done.

 

[ban-all-sheds]

We stitch drill holes as there is usually a cowl, casing or cover that will deal with untidy edge.

I may go that way.

Someone very kindly lent me a diamond core drill, and on Saturday I made a hole. Fortunately it was almost at floor level, so I was able to support the weight of the drill on my legs - the thought of trying to hold a 4kg drill at head height for the other hole I need (cooker hood) for the time it takes to get through 9" of brick does not fill me with joy.

 

[ban-all-sheds]

There are good diamond tipped cutting tools and there are poor diamond tipped fellas.

http://www.aldi.co.uk/uk/html/offers/special_buys3_14748.htm

 

[Albumen]

Will you be on a ladder doing that higher hole? I wouldn't do any diamond core drilling unless my feet were firmly on the ground. If the bit grabs it'll have you over.

I've done 2 holes in my bathroom for wastes.

The one I did with a diamone core was for the basin waste, using a 1100 watt makita rotary only drill. Kept grabbing and a right pain. Took ages, noisy and dangerous. And it was a brand new core bit. The man from Makita said that the drill I used wasn't really a diamond core drill. But it wasn't lack of power, just the sensitivtiy of the clutch.

The hole for the bath waste I did stitch drilling using a good SDS drill, then knocked it out with the rotostop and chisel.

I don't think I will do any more core drilling unless I really need a perfect hole. And then I'd want absolutely the right kit. If you have access to it then that might be ok, but I think stitch drilling is fine.

 

[ban-all-sheds]

Will you be on a ladder doing that higher hole? I wouldn't do any diamond core drilling unless my feet were firmly on the ground. If the bit grabs it'll have you over.

I'd need to be standing on something, as the hole will be centred at 2.1 - 2.2m above floor level, but I'd use something a little more stable and spacious than a ladder.

But you're right - grabbing and applying the torque to me before the clutch kicks in is another problem, so not just the one of holding 5+kg at that height for a long time. And fatigue is going to make it even more likely that it'll move out of alignment and bind in the hole.

I don't think I will do any more core drilling unless I really need a perfect hole.

I don't - the inside will be behind the decorative chimney of a cooker hood, and the outside is due to be re-rendered anyway.