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  1. #1

    Default How and when did 28,800 bph become standard?

    Can anyone say when the first 28,800 bph movement was introduced and who introduced it? May I take for granted that for a great while 18,000 was the standard frequency? Furthermore, may I take for granted also that GP introduced the 36,000 bph in 1965? It appears then, that 28,800 becomes the standards frequency around 1972. I wonder if, in an attempt to ostensibly stabilize the movement form outside forces, the idea sprung up to double the oscillating frequency, hence 36,000 bph. Then perhaps wear made the engineers rethink and settle back to the 28,800 we know today. Does this make sense? Can anyone point me to a learned treatise on the subject? As always, your kind courtesy and consideration are greatly appreciated,

  2. #2
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    Default How and when did 28,800 bph become standard? (RE: luger)

    Here is what I have gathered largely from a Swiss shop owner I spoke to when I was in Le Chaux du Fonds.

    The 36,000 bps watch was designed to go head to head with Quartz in the late 60's early 70's and was a very good timekeeper. I have a few of these in chronometer grade and their position rates are wonderful.

    Not learned, but physicist speculation is that the higher beat provided some stability but more important the higher spring stiffness made gravity effects on poise errors less important and thereby reducing position errors.


    The downside is that less amplitude would have had a bad effect on isochronism. This would not have been a problem because these were self winding watches and also the Swiss chronometer agencies did not and do not test for this. The result is that many COSC rate watches have to be re-regulated for wear by customers after getting their certificates.

    Whether or not isochronism was an issue, the Gerard Perregaux HF chronometer was milestone in accuracy and murdered everyone else at the Neuchatel trials until Seiko can in and blew away the entire competition.

    I have several G-P Hf chronometers and their position errors are hard to see with a timing machine. In Osterhausens book on Wrist Chronometers he reports similar outstanding performance by these watches.

    The problem was that the pallet arbors often wore out very quickly. This was a lubrication problem. It could not have been universal because Zenith uses the 36,000/Hr beat in their El Primero movements today and did all along. It had to be a problem in enough watches that it hurt. (If you are a manufacturer and have a problem with more than a few percent you have a a real problem) Possible the choice was special lubrication and inspection or going to 28,800. that is how excessive failure rates are treated in most industries. Zenith was a smaller player so they could do the extra diligence but the bigger guys just went to 28,800 when it appeared to solve the wear problem.

    The claim is that by backing off to 28,800 the problem was solved.

    That would date it to the early 1970's.

    I would not dignify this answer as learned but the guy who told me this man sure seemed to know his stuff. It does not make complete sense to me, but in support of this argument, Rolex used to buy El Primero movements for the Daytona and convert them from 36,000 to 28,800.

    If it was a repair/warranty it would not have been published anywhere easy to find.

  3. #3

    Default How and when did 28,800 bph become standard? (RE: luger)

    Dr. Jon,

    Extraoridnary!

    Thanks.

    This has bugged me for a long time (more of curiousity"bugging" than an intellectual one).

    Super!

  4. #4
    RonC
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    Default How and when did 28,800 bph become standard? (RE: luger)

    Does anyone have any info about the Longines Ultra-Chron? It is supposed to be a high-beat watch, but I don't know the details. My father has one and he's kept it in great shape.

  5. #5

    Default How and when did 28,800 bph become standard? (RE: luger)

    Dr. Jon, thank you. I will follow up a bit with Osterhausen's book.

    As for RonC re: the Ultra Chron, what would you like to know? It was introduced in 1967 to mark the 100th anniversary of Longines. It was guaranteed to keep time to within 1 minute per month (as was the GP). The movement was an in-house (as best I can ascertain) Cal 430 with 17 jewels; it was relatively thin, fast and used a Clinergic 21 tooth escapement made by FAR. AFAIK, this is the same escapement used in the Zenith/Movado El Primero (of 1969) and the Girard Perragaux HF (of 1966): they all ran at 36,000 bph. As best I can ascertain, 36k escapement came well before the 28.8k. At about the time the Ultra-Chron started to "sell," Longines introduced the Ultra-Quartz; I am not so sure the Ultra Chron was in response to the electric watch movement. In any event, in 1972, Longines then appears to pull the 430 out of service and uses the ETA 2824 in its place at 28.8k. Similarly in 1972, they reintroduced the Ultra-Chron movement as the 6641 beating at only 28.8k on 25 jewels although I suspect the added jewels were all inthe winding system...the bi-directional rocker switch for which was patented. The tricky part here is that the reduced frequency Ultra Chron used the same 21 tooth escapement; I am not sure about the rest of the going train but it did use a different hairspring and regulating system. I was under the impression that to change frequency one would have to change the entire gearing ratios of the going train and not just the torque on the mainspring; any thoughts?

    I have a theory (but no more) that Ultra-Chrons without the Longines Wings trademark are 430's and with the Wings are the slower movements (which would still qualify as fast beat at the time). I have not yet ascertained why the change to 28.8k. All roads point to the lubrication issue, but as Dr.Jon says, it did not stop Zenith. It also appears that every maker using the fast beat movement utilized dry lubrication (MOS2) on the escape wheel. While I suspect something was wearing out; I don't know what (but Dr.Jon's thought about pallet arbor wear is as good as any). I have seen commentary that the high speed "threw off the oil" but this is untrue because there was no oil to throw off!

  6. #6
    RonC
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    Default How and when did 28,800 bph become standard? (RE: luger)

    Thanks, Luger. Great info.
    Ron.

  7. #7
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    Default How and when did 28,800 bph become standard? (RE: luger)

    Th w17Jewel Ultra-chrons are wonderful. The basic problems are :
    1) Longines made a lot of them
    2) Some of them to my eye are the most garish ugly wrist watches ever made (Although I have a Zenith Square Time Commander that is a real competitor in the ugly watch category.

    It really hurts to see such a fine movement wrapped in a ugly design. Many ultra-chrons are more restrained and I do enjoy them.

  8. #8

    Default How and when did 28,800 bph become standard? (RE: luger)

    agreed; the ones in the Admiral one-piece cases are not so bad. BTW, any idea where to locate 431 NOS replacement parts?

  9. #9
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    Default How and when did 28,800 bph become standard? (RE: luger)

    Another thought. Assuming pallet arbor wear really was the problem the difference between 28,800 may have been how long the pallet rests on the banking between swings.

    teh escape wheel moves at about the same spped regardless of the beat so it slubrication is not a likley candidate.

    My new guess is that as the pallet moves it also moves the oil about and to retain good lubrication it may have needed a bit of time to recover to a preferred shape. Going from 36,000 to 28,800 may have provide the requisite recovery time.

    I have read elsewhere that WOSTEP training includes a lot of practice getting exactly the right amount of oil in place. It may be that at 28,800 this is still important but not so critical as it is at 36,000.

  10. #10
    collin
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    Default How and when did 28,800 bph become standard? (RE: luger)

    I am curiuos to know if imbalance in the pallet contributes to excessive wear at higher beat rates (much like a tuning fork vibrates)? Most likely I way off, but it seems to me that if lubrication was the main problem then impregnated lubicant technology would have provided some solution. Anyway, just conjecture. collin

  11. #11
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    Default How and when did 28,800 bph become standard? (RE: luger)

    At the higher beat rate the pallet did not move significantly faster only more often.

    A lot of detailed analysis has shown that imbalance was less a problem than the extra rotational inertia of a counterweight. This inertial made it harder to start and stop the lever.

    I think the industry thought the same thing you suggested and it was probably correct most of the time, but failed often enough that they could not live with it.

    A lot of engineering of mass produced items goes this way. It may also be that impregnated lubricant technology might do better now that 30 years have elapsed but the overwhelming preference now is precisely applied synthetic fluids.

  12. #12

    Default Re: How and when did 28,800 bph become standard? (RE: luger)

    [whisper uid=474]
    Jon, you mentioned that a problem with the Longines Ultra Chron was that they made alot of them. What did you mean by that? I quess I mean, what is your idea of a lot or overproduction? thanks
    [/whisper]

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