Were to centre hole????

[caslin]

need to cut a 5" diameter hole in a brick wall for a waste pipe. Long story but girlfriends sink currently leaks as waste pipe goes uphill into an ancient indoor down pipe.

Anyway my question is do i centre the core drill in the centre of the brick or in the mortar? sounds a daft question but only if you already know the answer.

Thanks in advance for your help.

 

[muggles]

You centre it where you need the centre of the hole, simple as that

 

[caslin]

but i could always extend the pipework, in an ideal world which would cause the least damage ie the best hole. Dont want to put centre in mortar if i could possibly dislodge two bricks.

Its never goes straight forward for me.

 

[Burnerman]

It really doesn't matter with a core drill mate - the pilot hole will be happy in either brick or mortar, and the core bit will follow.
John

 

[noseall]

Logic would suggest avoiding (often partially filled) perp joints for fear of the pilot bit wandering.

 

[neds]

Logic would suggest avoiding (often partially filled) perp joints for fear of the pilot bit wandering.

This, I try to avoid the mortar bed if at all possible. I tend to drill a 10mm hole straight through first to give you a guide. This way you can drill from both sides and avoid major breakouts.

 

[PrenticeBoyofDerry]

I do the same as neds, pilot a hole straight through both sides/cavities.
So you'll need a long bit.
The bit size, I keep to the same as the pilot on the core drill, then drill partly through one side then the other, to stop the masonry splitting or breaking.
I'm not to fussed if it,s on mortar or not, as long as the hole is in the right place.