Core drill for waste pipe

[pcsparky]

I'm planning on buying a core drill to pass a 40mm waste pipe through our medium density block walls. Should I get a 40mm or 42mm drill core?

I can get hold of a 40mm one much cheaper than a 42mm for some reason but not sure if there would be enough play.

 

[2face]

screwfix armeg range do a 42 mm core. well priced too

i chop away the brick a nats on the outside so the collar of the fitting fits flush in the brick work.

 

[Razor900]

The 40mm is cheaper cos its too small! The OD of the pipe is 42mm but as above the hole needs to be a bit bigger to accomodate the fitting, personally I use a 50mm bit most of the time!

 

[clf-gas]

Personally I only ever core for flues. Stitch for anything big and good old hammer and bolster for waste.

 

[bengasman]

get a 50mm, will make your life much easier, 4 mm is still not a lot to fill up after install