On 26 Mar 2021 at 13:39:06 GMT, "The Natural Philosopher"
wrote:

On 26/03/2021 11:26, Bert Coules wrote:
SH wrote:

I usually use the next size up diameter for the tile so that the 2nd
drill bit used to drill what's underneath the tile does not catch on
the hole within the tile.

I can see the sense in that, so thanks.Â* But in my case - as advised
here - I need the wall plug to be a close fit to the hole in the tile to
ensure a good grip when it expands.

IME there is absolutely NO grip to the plasterboard at all. SH's method
is intelligent for e.g tiled MDF, but in terms of tiled plasterboard you
are attaching to a tile that spreads the load to the plasterboard and
other tiles.

In which case, don't use a traditional wood screw with an unthreaded shank,
especially one on the large side for the plug. Use constant diameter
fully-threaded screws. Otherwise you can apply huge forces to crack the tile
as the screw goes fully in. DAMHIKT

--
Roger Hayter