Bathtap Nut

[spud1962]

I've lost the little nut that secures the tap "head" to the top of the pillar (with the knurled end)on my bathtap. Blow me - but I can't find anything to replace it.
I've tried a 4mm x 12mm machine screw with a slotted pan head, but its just a fraction too narrow. The next size up is 5mm but its just toooo wide.
Looks as if it needs to be 4.5mm? Any ideas

 

[Bahco]

Take tap to local plumbers merchant who will have millions to choose from

 

[breezer]

millions to choose from

could take some time then?

 

[spud1962]

thanks bahco. I'll go and see one, but taking the tap off was one thing I was hoping to avoid.

 

[kevplumb]

dont you know a spark they use some funny size threads
talking of funny threads wheres breezer