Hi Biggles. It used to be so,I think,that EP oils were to be avoided in 'boxes which had phosphor-bronze bushes,as is the case of the Dragonfly,Marks and most classic machines,but that is not neccessarily so now,maybe(!?) However,I am currently using ,in my D'fly,Morris's Golden Film AG90 Classic Gear Oil,which they emphatically state is OK with phosphor-bronze .All the best,Ken.