Bulova 30 Jewel micro-Rotor 12EBACD SS 417660 N2/M8 = Case Dimensions: Width w/o Crown: 37.35 mm = Length:41.00 mm hidden lugs = Depth: 6.65 mm wo/crystal, 10.10 mm w/crystal = Lug Width:19.00 mm = Crystal: 32.05Dia mm, in watch. Domed acrylic = Crown: 4.00Dia mm, signed with a “C” (Caravelle replacement?) Inside case back: Inscriptions: R/; 7283; Swiss = Engraving on outside case back: BULOVA; 417660; N2; Stainless Steel = Movement: 12EBACD Automatic Micro-Rotor 30 Jewel = Engraving on Movement: BULOVA WATCH CO; 12EBACD; 30 Jewels; Swiss; M8. Under Balance Wheel: SX; D = Notes: This is my third example of this model, and the second with the avocado green dial. I am not able to resist this watch if it is in nice condition and isn’t ridiculously priced. Another reason for the acquisition is that I am developing a theory about this model, which apparently was not well documented by Bulova. All three of my watches contain, arguably, the best version of the Buren 1321 ever produced. From what I have seen, Bulova required Buren to install the larger jewels on each end of the self-winding works, even on the 17 jewel version. My theory is that this particular Bulova model, which has exceptional build quality and better materials than usual for Bulova, was a one year only statement watch. As examples, the case back is three times the weight of a typical Bulova, each movement was secured to the case with dedicated polished case clamps, and the back o-ring is of better quality…all three of mine are still usable. I embarked on this examination due to the unusual combination of a 1968 movement with a 1972 case. The three I have each are of this same configuration. There is another green dial example on the bay that has a similar serial number and an identical N2 case, however there is no photo of the movement. It is listed as a 12EBACD though, and it is likely also an M8 date code. At $728 Canadian I am going to have to pass on that one. So why produce this departure from the typical Bulova date scheme? I think it is the circumstance that Bulova found itself in 1972, perhaps having a quantity of 1968 Bulova badged Buren 1321 movements without cases. Bulova was getting re-badged 1321 movements from the Swiss company Buren since at least 1964, along with American watchmaker Hamilton, Swiss companies Baume-Mercier, Bucherer,
apparently my text was too long. Here is the conclusion of my observations:
IWC, and others. In 1966 Hamilton bought Buren. Then in 1969 Hamilton ceased producing watches in America. Two years later, in 1971, SSIH (later the Swatch Group) acquired Hamilton, including Buren. SSIH was basically the merger of Omega and Tissot. In 1972 SSIH liquidated the factory in the Swiss town of Buren at the River Aare, where these movements were made. In 1972 this would have put Bulova in the position of not being able to have another micro-rotor made for them. It would also mean that having Buren make new bridges engraved with the current date code for their old stock could not happen. It is likely that when Hamilton moved to Switzerland in 1969, that Bulova was no longer able to economically procure the Buren movements. Many hours in the MyBulova database have suggested this: 1. All Ambassador models from 1964 until 1970 had the micro-rotor. 2. Only Ambassador models had the micro-rotor until 1972. 3. In 1970 Ambassador models began having 11 ANACO and 11 ANAC 23 jewel movements, an unknown 17 jewel movement, and an undated 12EBACD movement. 4. The last Ambassador I found in MyBulova with a 12EBACD was 1972, the movement was date coded 1968, and it is an unusually premium version with a red dial. The last vintage Ambassador was an unremarkable 1973 without a jewel count on the dial, and almost certainly not a micro-rotor .
So this is what curiosity will do for you . That and $3 will get you a grande at Starbucks. I would suggest that this is a model that is unusual, and worth having. Good luck getting one if I see it first (grin).
The Micro-Rotor movements also had a tendency to experience wear of the rotor axle which would then scrape the inside case back. It rotates in a jewel, the same as most of the Rolex Perpetuals, (Which suffer from exactly the same flaw) Micro-rotor parts are much harder to get these days, so servicing can be an issue, depending on how well it was taken care of.
One reason we don't see micro rotor movements anymore, (with Patek being a high end exception) is that the reason they existed was to make a slim automatic watch. Thicker watches have been in vogue for many years now, but this is not the main reason either.
The Micro Rotor does not wind the watch as well as a full size rotor, it's just physics. Patek partly gets around this by using a solid gold rotor for increased mass.
The mechanism is notoriously 'grindy' when winding, and this is due to a mechanism design to prevent the rotor from spinning during manual winding. I haven't serviced a Patek micro-rotor, so I can't speak to how it feels while winding.
So basically the watch suffered from low power reserve, and that rotor axle issue. It was an ideal platform on which to build one of the world's first Automatic Chronographs, a joint project by Hamilton/Buren, Heuer, and Breitling. The integrated automatic winding system is buried under the chronograph plate, and allows for a slimmer automatic chronograph. Bulova also had a version of this, which is affectionately known as the 'Parking Meter.'
There have been some bizarre and spectacular automatic watches made over the years, some were very over-engineered, some you might say were too simple. Many disappeared for a variety of reasons, not the least of which was cost. Bulova was able to make outstanding in-house automatics, and probably saw the Micro-Rotor as 'gimmicky,' but in the end, it was more costly to produce (and procure) and Bulova had been doing well without it. It's a curious part of horological history, and I can say the design does have its afficianoados and collectors, as there were a lot of them used by various makers over the years. The 30 jewel version is considered to be the top.
I'd agree with the 'Bulova 30' ID for now also.
In reply to The Micro-Rotor movements… by Reverend Rob
Hi Reverend Rob
Thank you for the detailed evaluation of the micro-rotor. If I am not mistaken, you are also the person who enlightened me to the Dubois-Depraz caliber 11 that was used in the Heuer, and a number of other chronographs. Would love to get my hands on that one! I have read several forum accounts of the rotor axle failures you mention. These comments were usually accompanied with the opinion that the larger end jewels in the 30J, and I believe some of the other high jewel count Burens used in the other brands, were considered something of a cure for this. I would appreciate your expertise to refine my understanding of effect the larger jewel had on the longevity of the movement. What I alluded to was that all of the Bulova 12Exxxx movements I own, including the 17j, each have the larger end jewels. I also have about 10 of the Hamilton versions, mostly 17j, and these all have the smaller end jewels. So now, when possible, I try to acquire the Bulova versions. Am i correct in this belief?
I got a kick out of the "grindy" characterization of the winding feel, so it seems did bakerthebulovaguy (smile). I use a different word---"crunchy" (I borrowed that from John Mayer). It is different, but now I expect it and would be surprised if it felt otherwise.
I agree that Bulova did not actually need the micro-rotor, considering the tasty USA movements that are certainly iconic to the brand. However, I don't believe I have seen even the best 6 adjustment 23j, or the 7AK, with the level of finish and polish of the Bulova version of the Buren. You would know first hand better than I. My feeling is that it was a prestigious flagship engine in that brief period, and a win-win for both companies, until it wasn't. By the way, where would I get an image of the "Parking Meter"?
I also concur that the Buren was a movement that temporarily solved a thickness issue, and that certainly went away with the Hamilton 619; 623, and 639 works. And was blasted out of necessity with the eta 2892. But they are such elegant items of refined engineering that I believe there will always be a place in collections for them.
Anyhow, thank you for the very thoughtful and informative response. You are an asset to the panel for sure.
jimmy
In reply to Hi Reverend Rob Thank you… by gmmy775
Very kind, Jimmy thanks! We have a Bullhead Parking Meter here:
http://www.mybulova.com/watches/1973-chronograph-8598
The same movt is found in the Bulova Chronograph 'F'.
As far as jewel size, either as axle bearings or the large ones that sandwich the floating pinion, these make no difference to the axle wear. Rolex has had the same issue with all the automatics that use a jewel setting with the solid axle. The axle wears, and the rotor wobbles, often striking the movement in the case of the Rolex. The remedy is to replace the axle and sometimes the jewel, but eventually the entire rotor must be replaced. In the case of the Micro-Rotor, I can't remember seeing any wear against the movement itself, but it is possible. Usually the rotor hangs and scratches the case back, and you can hear it.
The fit and finish is very good, but I'd say all 30 jewel Bulovas have extra attention to quality, these were top of the line at the time. Like you, I'm also a fan of the robust case designs Bulova was using, nice and heavy.
As you say, a good collection should always have one of these.
The Heuer Cal 11 watches are pretty pricey, as are the Breitlings, but Hamilton also made a version of this, still pretty pricey. A lot more buyers are aware now of the extent of the usage of the movt, so prices are all way up, there's no real way to get an 'under the radar' version. Thanks a lot, Internet.
In reply to Very kind, Jimmy thanks! We… by Reverend Rob
Ah, it is the floating pinion jewel that I was referring to. Thank you for clarifying that to me. Aparrently that was also a potential issue area in these. Now that you explain it, I do understand the rotor contact problem. I have seen that on more than one brand, including an Omega Seamaster that I own. Knock on wood, I do not that I recall that on any Bulova I own, yet.
I will be looking for the "Chronograph F" now, as the lowest price on a cherry "Parking Meter" I found was 4999. Thanx again, I feel more comfortable shopping for one now.
In reply to The Micro-Rotor movements… by Reverend Rob
In reply to No Question from me Jimmy-… by Geoff Baker