What drill bit and plug for my radiator wall ties

[Mark Lewis]

Hey

I have some large cast iron rads in my home and they are currently unsecured to the wall. Ive bought some rad ties but they didnt come with any plugs. The screws are as follows:

D8mm x L150mm with roughly 60mm of thread

What mm drill bit should I use for the holes and what mm plugs please?

I will need to buy a 300mm drill bit to get through the radiator bars into the wall behind so want to just get it right before buying the bit and plugs

Am I right in thinking a 8mm screw needs a 9mm plug in a 10mm hole?

Any advice most welcome

 

[Burnerman]

10mm hole, with a 10mm quality plug such as Fischer should do it! Any smaller plug than required will just spin in the hole.
John