Strap-on boss hole size?

[mickfitz]

Hello

I've got a strap-on boss with 40mm grommet for a 110mm soil pipe.

I've gonna fit it tomorrow, but I'm still a bit unsure how big to drill the hole in the soil pipe. On the inside of the boss is a raised lip that I'm assuming will fit inside the hole?

I'd be grateful if someone can please tell me how big to drill the hole in the soil pipe?

Thanks in advance ... Mick

 

[gas4you]

Drill the hole to the size of the 'raised lip'. I think it is 50mm.

This lip locates in the soil pipe, so the boss glues flush on to it.

 

[mickfitz]

Thanks mate

Mick

 

[jas05]

yep, the O.D. of that lip is the hole size you want

if its an Osma Strap Boss a 2-1/4" holesaw will do fine.