On 26/03/2021 11:29, Bert Coules wrote:
Dave Plowman (News) wrote:

Masking tape can work - starting out with a small drill. Or if you have
one of those old tile scorers - the sort you use before snapping them.
Just used to break the glaze.

Since the surface of the tile immediately around the fixing holes will
be covered by the base of the mounting brackets for the grab rail, I
have wondered about trying to scratch off the glaze where the holes have
to go in order to provide better grip for the drill bit.Â* Something to
try on my test tile.

the core drill will wander all over the place and do that...;-)

I think the ONLY thing that worked for me was a bit of MDF with a 6mm
hole in it.


--
Theres a mighty big difference between good, sound reasons and reasons
that sound good.

Burton Hillis (William Vaughn, American columnist)