Old porcelain dials from pocket chronograph

I hope that someone can help with information about old porcelain dials. I show two dials that are for Omega 18’’’P savonette (SOPB) chronograph pocket watches. Each dial has the same marking on the back – ‘415’ and (I think) ‘BF’.


The old dial is from an Omega 18’’’P savonette pocket watch – which is in poor state, only for parts. The new dial is exactly that, ‘NOS’, never used – but the markings are the same.

The 415 does not relate to diameter (which is 42.85 mm) and I presume must be a reference number (meaning for this calibre). The separation between the sub-dial centres is 21.05 mm.

I assume (but don’t know) that the ‘BF’ relates to the manufacturer. On the new dial, I could just about believe that the ‘B’ is a 13 (so it could be 13.7) – but looking at the old dial, it seems to be ‘B’. The ‘F’ could possibly be a ‘J’, I don’t know.

Can anybody throw any light on a dial manufacturer to whom the ‘BF’ might relate? And is the ‘415’ a reference number – in which case, it would be good to have a list of their references!

I show below the dials in correct orientation:


And finally I have noticed other dials which are marked ‘EAD’, presumably another manufacturer – I show an example.

Can anybody enlighten me?