5BD "sealed jewel" movement?

Submitted by tkm3rd on

Hi All,

I have a fair number of Bulova and other movements which I have taken apart, cleaned and reassembled over the past 2-3 years. Many of them have been ladies movements such as the 1974 5BD 23 jewel movement below; however, I have never come across what seem to be jewels without the jewel "oil sump" accessible - it looks almost as if they are "sealed" .  

That can't possibly be right, can it? If it isn't possible, how does one go about oiling the jewels and pivots properly?

**Please excuse the dirt as these were taken prior to cleaning.

Top of train bridge showing jewels 5BD

Showing "sealed" jewels on 5BD

Thank you for any information. Yes, it's off to the cleaning machine now!


Posted May 27, 2024 - 10:37pm

I have a few of these 5BD's in my parts drawer and took a look at one.  If you turn the bridge over you can see the hole jewel with the oil sink on the underside so you would oil on that side either with an automatic oiler or oil as normal and then draw the oil through to the 'capstone' using a thin wire like this or you can take an old USB or similar cable and strip it and take out one of the thin wires. It doesn't seem like a great design as I doubt that during cleaning you can get the jewel as clean as you would if you could remove the hole jewel.

Just for fun I pushed one of the jewels and its setting out of the bridge and was able to remove the hole jewel from the setting. I was able to get the hole jewel back in but I don't think it is designed with this in mind as it kind of chewed up the edges of the setting.



Posted May 28, 2024 - 8:52am

In reply to by GuyMontag

Thank you for the info. 

I have to imagine the engineer behind that bright idea was asked to leave Bulova. LOL!