Something Unusual About The Caliber BVL 138 and its Jewels, Introducing Spacer Jewels
WOW. OUR MEMBERS ARE SUPER EAGLE EYED! I never ceased to be impressed by the readers on WatchProSite! Very impressed.
The Version 1 Caliber BVL 138 has 36 jewels. The Version 2 BVL 138
caliber only has 31 jewels. A funny detail about the V1 caliber is that
many of the jewels aren't traditional pinion jewels. Meaning they
don't hold a gear or a pinion in them. Many of them are actually
"spacer" jewels, meaning that they're there so that way space can be
maintained between the plates (since the watch is so thin)! You'll notice many of these jewels don't have a little hole in the middle where the pinion for a gear would go into. This is
considered to be fairly unusual. It's also considered to be an elegant
technical solution and an expensive solution, as jewels are more expensive than metal spacers, metal spacers can also just be CNC'd in the plate, whereas jewels would likely need to be pressed into the plate by a human. I haven't studied the V2 extensively, but it
appears most of those spacer jewels have been removed. Possibly to cut costs, or to improve the overall movement, or both.
Version 1. Notice the jewels on the top left quadrant, many of them
don’t have holes with metal pinions in them. Many of the ones without
holes in them are ”spacer jewels" that are there to maintain space
between the narrow plates. This is HIGHLY UNUSUAL architecture and not
commonly seen nor discussed.
Version 2, notice many of the spacer jewels have been removed compared to the Version 1 movement.
Almost all the jewels present in V2 have metal pinions in them. The rotor also looks a little bigger to me. So it seems like there are multiple changes between V1 and V2.
I will get in contact with our man on the inside at Bulgari and get some more details hopefully. Again, super impressed with the WatchProSite community for noticing this super minute detail. And Tim Mosso is definitely a greatly detailed fella! Without him mentioning it, I might not have noticed for months! Thank you WPS members and Tim Mosso!
Photo credit to Bulgari's website, both of these pics come from Bulgari's website.