Monobloc will not tighten

[m_13]

Thanks to everyone who has offered help and advice so far

We've bought a Crosswater Hey Joe! Basin Monobloc (http://www.crosswater.co.uk/productsingle.asp?BrandID=19).

We have a Twyfords Pure basin with a 35mm tap hole.

The tap has narrow metal threaded rod which goes into the base of the tap and the two flexible tap connectors and the threaded rod go through the hole. The threaded rod then tightens with a nut which in turn tightens a horseshoe washer.

There are two issues which may be related!

When the nut is tightened as tight as it can on the thread the tap still rotates on the top. As there is no washer between the metal base of the tap and the ceramic top of the basin, the turning is marking the basin.

The second problem is that the tap hole has a slightly raised rim around it. This means that the base of the tap is not sitting completely flat.

Any ideas on how I can resolve these two problems. I have wondered about putting Plumber's Mait on the surface around the tap hole to level it out and see if it resolves both problems!

 

[kevplumb]

put a rubber washer under it

 

[m_13]

Thanks Kev but isn't that going to raise the tap even further from the basin top and make the gap bigger?

Don't know if you've had chance to follow the link but the image on the right hand side is the tap and it has a square plate that goes between the tap and the basin. The square plate is turning on the basin top (and marking it) and the tap is turning on the square plate (and marking it)!