I have had Nortons for over 50 years but never managed to find a grease gun that fits the nipples on a Dommy. Its time I solved that issue. What am I missing?.
Which, in my experience, never fit properly and you end up with grease everywhere. Old timers suggested that a bit of cotton rag between the nipple and the nozzle worked but never for me.
I replace them with modern type nipples that current grease guns will lock ("hook") onto. Not original but I suppose if you really wanted to you could fit the new type to grease then refit the old ones for "originality".
1/4" BSF thread if I remember correctly.
The one I would like to service is on the brake lever ,and that is extended to retain the lever,so no modern fitting . Ah well.
The original prewar type without the locking ball seem to be unavailable anywhere. I'm keeping mine on the old 16H for appearance sake. When I put the bike back on the road a couple of years ago I took each one out in turn and put a modern one in so I could pump the dried out greaseways clear (girder forks). Then put the old ones back. A scrap of cotton cloth (old shirt) then seals the connection and allows the originals to work fine.