Flags and Slabs - cutting a hole in a flag

[rob roy]

Hi all,

I would like some advice on cutting a hole in a Stonemarket Mill Stone flag.
The 620X310 will be covering a drain so i would like to
drill a hole 2-2/12 inches in diameter to allow drain pipe
to go through to the drain.
Is it feasable to drill a lot of small holes and chip out
the middle - or will the flag break?
any help / tips gratefully received.

regards

bob

[alan ditchfield]

this may be possible but at a guess i would say the flag would break if you really want the hole to be round and only a couple of inches in diameter the best option is to use a diamond core drill but there not cheap to hire,and v expensive to buy.

[84-1093879891]

What you are describing, Bob, is known as "stitch drilling" and, while it is laborious and less than ideal, it's the simplest option for DIYers.

A core drill gives a perfectly round hole, with no jagged edges, but, as Alan said, they can be expensive to hire for a single cut. The Hire Co's make a basic charge plus wear is charged by the millimetre, and even with just a single cut, you can bet your bottom dollar they'll claim you've worn away a full millimetre!

If you mortar-in around the pipe once it's in position, the jagged edge left by stitch-drilling will be hardly noticeable.