Pues sinceramente creo que 36000 hora
Me he dado una vuelta por la gueb para sacar más datos y me he encontrado con ésto. A los que nos gustan los Longines nos encantará.
El problema es que está en inglés ... osease que los que lo tengais oxidadillo os vendrá de perlas y a los que ni fú ni fá pues les recomiendo el google translator Por cierto, los enlaces en lo que os copio son de órdago.
Ahí va el tocho... es gordo, pero vale la pena... sorry pero me veo muy vago como para traduciroslo enterito
The Longines Ultra-Chron: Caliber 431
A Brief History of the High Frequency Watch Movements with Specific Attention to the Longines Ultra-Chron
[The following is a synopsis of the more detailed article which appeared in the Bulletin of the National Association of Watch & Clock Collectors, December 2007]. A full copy in pdf-format can be foundhere.
Wrist watches with oscillating balances that vibrate at 36,000 beats per hour are commonly referred to as “fast-beat,” "hi-beat" or “high frequency” movements. Beats per hour (hereinafter “bph”) refers to the number of half swings the balance makes in an hour. In 1967 the Longines Watch Company introduced an excellent, nicely finished and exquisitely engineered example of the high frequency movement known as the Ultra-Chron. This movement was to commemorate the 100 year anniversary of Longines, founded in 1867. What follows is a brief history of the development of the high frequency mechanical movements in general and the Longines Ultra-Chron movement, in particular.
II. Background of the High Frequency Movements
A fast beat balance dissipates more energy and requires more torque from the mainspring. The higher the frequency of the balance, the more energy it consumes and therefore the larger its barrel must be. For a long time it had been considered basic that in the ordinary watch, 18,000 bph represented the optimum compromise. This value produces an isochronous assembly (i.e. one having the same period of oscillation regardless of amplitude) possessing good dynamic stability, while avoiding excessive energy losses so that a barrel of acceptable dimensions provides a power reserve of 35-38 hrs.
By the 1960’s it had already been know for some time that at oscillating frequencies greater than 18,000 bph, the disruptive effects of external vibrations and positional changes decrease progressively as the frequency increases. Notwithstanding, until 1966, it was not possible to increase the oscillation rate to over 21,600 bph, since no means were known to give such watches a sufficient power reserve. The minimum acceptable operating power reserve of a portable watch is considered to be 35 hours. While an oscillating frequency of 18,000 bph had been sufficient for pocket watches for innumerable years, fast-beat movements were developed for wristwatches to allow for greater precision, when mainspring technology allowed.
Today, the standard oscillation rates encountered are 21,600 bph or 28,800 bph. However, A. Schild (hereinafter sometimes referred to as “AS”), Baumgartner, Citizen, ETA, Favre-Leube, Felsa, Girard-Perregaux (hereinafter sometimes referred to as “GP”), Heuer, Longines, Mido, Movado, Ulysse Nardin (hereinafter “UN”), Zenith, Zodiac and perhaps others investigated high frequency movements in the 1960’s and Seventies. They confirmed that the high frequency watch exhibited greater consistency of rate between the vertical and the horizontal positions and further that over a twenty-four hour period suffered less drop in amplitude making them more isochronous.
Favre-Leuba, for example, experimented with the fast beat movement, testing four hundred otherwise identical movements supplied by Girard Perregaux. Favre-Leuba obtained the following comparative figures from two hundred movements oscillating at 21,600 bph and two hundred movements oscillating at 36,000 bph. The mean variations were 1.1 sec. at 21,600 bph and 0.7 sec. at 36,000 bph. Similarly, the greatest deviations were 2.4 sec. and 1.6 sec., respectively; and positional variations were 4.8 sec. and 2.1 sec., respectively. The superiority of the fast beat movements is attributed partly to a smaller drop in amplitude when moving the watch from the vertical to horizontal positions. In moving the watch from a vertical position to the horizontal the following changes in amplitude were found: at a state of full wind: 33 degrees at 21,600 and 20 degrees at 36,000 bph; after twenty-four hours: 26 degrees and 17 degrees respectively.
Notwithstanding, apart from Zenith, interest in the 36,000 bph movement died out in the mid 1970’s probably in no small measure due to the advent of the quartz oscillator watches. Although in a publication entitled "Ultra Chron vs. Ultra Quartz" produced for Longines-Wittnauer franchised dealers in 1969, the near-future role of the quartz watch (a technology pioneered by Longines) was marginalized as advanced, certainly, but prohibitively expensive for the consumer., Moreover, despite the onset of the Quartz Crisis, quartz watches did not actually overtake mechanical watches in popularity until 1978. The Zenith “El Primero,” also introduced in 1969 is unique in that it is still in production, despite a hiatus until 1980. It represents not only the high point of the development of the high frequency wrist watch movement but it is also its last bastion.
The high frequency watches were distinguished from contemporary products by good time-keeping precision and reliability. By doubling the oscillation frequency from 18,000 bph to 36,000 bph, the watch was far less susceptible to timekeeping error and the sensitivity of the oscillator to external influences was diminished. In actual use, on the wrist, errors introduced by the inertial forces of rapid arm movement are lower in the fast beat movement. As the final result, the watches had a precision far greater than other watches known up to that time.
To achieve their rate of oscillation, the high frequency movements incorporated a Swiss lever escapement with a twenty-one toothed escape wheel. The conventional escape wheel employed only fifteen teeth. The escapement system was designed by A. Simon-Vermont for the Frabriques d’Assortiments Réunies (FAR), in Le Locle, now part of the Swatch Group. The system was called the Clinergic 21 Escapement System. With the fifteen toothed escape wheel the same oscillation rate would have required an additional runner gear between the fourth wheel and the escape pinion.
III. Development of the First High Frequency Movements
As noted, wrist watches with oscillating balances vibrating at 36,000 bph are commonly referred to as “fast-beat,” "hi-beat" or “high frequency” movements. The first of the “high frequency” watch movements were developed in 1961 by Girard-Perragaux as the GP 31.7 and 32.7. These were based on the A. Schild's 1920, which in turn was based upon the AS 1716 caliber. [N.B. the Longines 431 was not based on the GP/AS ébauche. It was completely discrete.]
Girard-Perragaux introduced the fast beat wrist watch to the world at the Basel Fair in 1966. In 1965, however, it was the GP 32.7 which was the "very first" watch movement with the 36,000 bph frequency. But it was the GP 32A which was the first serial production high frequency movement. This was the movement which GP made use of for the Observatory Chronometer Competition Trials. The movements measured 11 1/2 lignes and featured a date, but neither quick-set date mechanism nor "hacking" seconds. The stop-second feature was introduced in the 1968 GP 42, which more significantly featured an improvement in terms of a weak point of the GP 32 series: a relatively low power reserve. The fast-beat Clinergic-21 escapement required a lot of energy, which, in turn, resulted in a lowering of the power reserve. In order to maintain a stable rate for GP´s fast-beat movements, a new mainspring was required to supply the torque necessary for this most effective, but power-consuming escapement. GP was awarded patents for its proprietary solutions for both the power reserve issue and for fine regulation of the daily rate of the movement.
IV. Some Misconceptions about the Ultra Chron
It is not clear that GP held the patent on the "high frequency movement." Numerous makers produced high frequency movements and many found solutions for a variety of impediments. GP clearly had patents on a mainspring design as well as a proprietary worm-geared regulation system. In fact, it was as early as 1939 when Longines introduced the famed “Olympic timer” chronograph. Able to time events to 1/10th of a second, it was fitted with a very rare type of escapement for the period, beating at 36,000 bph. Measuring instruments and sports chronometer, which can record times of tenths, fiftieths or hundredths of a second, used small balance amplitude but a balance with a high moment of inertia. Their structures are cumbersome, costly, delicate and further unsuited for portable watches given power reserves of not more than 10 hours. As for the improved mainsprings, Longines' Ultra Chron's from 1967 already exhibited satisfactory power reserves of 42 hours, in a relatively thin movement.
There is a misconception that the high beat movement was a collaboration among several makers. Certainly, optimum operating precision required reduced friction between the moving parts, which itself required high precision in the manufacturing process, as well as improved architecture. A look at the architecture of the various movements might suggest otherwise about the theory of collaboration. Furthermore, the Clinergic 21 had been in production for two years when no less than nine brands showed 36,000 bph wrist watches at the Basel Fair of 1968.
However, it was at that Spring Fair of 1967 that Longines launched their version of the self-winding wrist watch with a 36,000 bph movement. The movement was cataloged as the caliber 430 although it was commonly known as the Ultra-Chron. There is a misconception that the Ultra-Chron's were made in excess. This seems to stem from a skewed interpretation of popularly available serial number charts. By its one-hundredth year, Longines had produced some 15 million watches. Ultra-Chron's appear with serial numbers in the not only in the 13 and 14 million range but also in the 50 million range. Either of two things occurred: Longines production went into overdrive producing in a brief span of some five years more than twice the production of 100 years of effort or; the numbering system was radically altered. In fact, on February 19, 2001, Longines celebrated it thirty millionth (30,000,000) timepiece.
V. To Commemorate the 100th Anniversary of Longines
The Longines Caliber 430 was introduced in the Ultra-Chron models of 1967. The Ultra-Chron was intended to commemorate the 100 year anniversary of the “the most honored watch [company] in the world.” The Longines Francillon Co. was founded in 1867. Although it was not the first caliber to oscillate at 36,000 bph, the 430 was ostensibly the first mass-produced automatic mechanical watch with such a heightened oscillation frequency, reasonable power reserve and, it was guaranteed accurate, on the wrist, to accuracy within one (1) minute per month. Longines warranted adjusting the watch to this tolerance if necessary. A contemporary print advertisement read: “Every Ultra-Chron is to gain or lose no more than a minute a month—one out of every passing forty-three thousand minutes.” The guarantee was good for one year. The high frequency movement produced a stability of rate that had never before been achievable in actual wear. Side bar notes , 
VI. A Description of the Ultra-Chron Movements
a. Derivation of the name
It has been suggested that the name “Ultra-Chron” derives from the combination of the Latin word “ultra” meaning "beyond the range or limits of" and the Greek word “chronos” meaning time (or the more apt word derived therefrom “chronometer”). Given that a modern chronometer may be defined as a timekeeping apparatus that is expected to be accurate to -4/+6 seconds a day (which may roughly be translated to -2/+3 minutes in a month), this would be a fair supposition of the meaning of the name since it was claimed that the 430 series could deliver +/-1 minute of accuracy per month and thus, was beyond the range of a chronometer. Click here for a brief discussion of the exceedingly rare Longines' certified chronometer Ultra-Chron.
b. Description of the movement
The base was designated caliber 430, indicating hours, minutes and seconds. This seventeen (17) jewel hi-beat movement was round and measured 11½ lignes (25.6 mm) and 4.30 mm in height. A movement this thin allowed Longines to encase it in cases of slender proportions and with the usual Longines style, yet they did not always take advantage of the movement's svelte dimensions or their own historical and undisputed flair for watch design. Many are quite simply unattractive watches. However, some encased in the thin Admiral one-piece cases were attractive.
Several variations were derived from the base movement. The calibers 431 and 433 have the date complication which increased the height to 4.80 mm for both despite the absence of a seconds hand on the latter; the 432, like the 430 but without a seconds hand and a height of 4.30 mm. The caliber 430 series found a home in one, two and three piece cases which carried such style names as “Ultra-Chron,” “Admiral HF,” Conquest and "Olympian." The “HF” indicated “high frequency.”
c. Description of the escapement and its lubrication
The escapement ran at 36,000 bph or stated another way, at a rate of 10 vibrations per second. Click here to see and hear the Ultra-Chron escapement in action. In order to sustain this balance oscillation rate, a screw-less three spoke Glucydur (beryllium-bronze) balance with a non-magnetic, self-compensating, flat Nivarox hairspring was employed. The hairspring’s composition rendered it insensitive to temperature changes and ordinarily encountered magnetic fields. More specifically, it was necessary to employ the same escapement used in the pioneering GP movement: the Clinergic 21 anchor escapement, developed by Frabriques d’Assortiments Réunies (FAR). And while the gearing of the entire going train would intuitively seem to have to differ slightly from the norm, most notably, it was the steel escape wheel utilizing 21 teeth instead of 15 teeth, mated to a pinion with seven leaves and the 100 toothed fourth wheel that made the difference. The Clinergic 21 system produced mean daily error rates of 3 seconds, without major adjustment. 
As a result of the high balance rate, the escapement had to withstand severe strain. For this reason, along with the fact that at such elevated speeds, the lubricants of the day would simply have tended to be thrown off the teeth, Longines opted for dry lubrication of the escapement with molybdenum bi-sulphide. See sidebar regarding molybdenum lubrication. During servicing, the escape wheel should not be cleaned because it is treated with the dry lubricant. Nivarox, the developer of the escape system introduced “Lubrifar” in the early 1970’s, a molybdenum disulfide (MoS2) lubricant which remains in use today for the escape wheels. [46*] Similarly, the pivots and pallet stones of the pallet-fork should never be lubricated. Otherwise, discrete oiling of the pivots with Synta-Visco-Lube was recommended. This caliber series does not have the seconds hacking function. Regulation of the daily rate on the 430 series is via a two-phase design with the rough adjustment of the rate adjusted by direct action on the pin-holder element and fine adjustments via the eccentric screw of the micrometer regulating devise.
VII. Other Surprises of the Ultra Chron
a. The Calendar Mechanism
The calendar mechanism of the 431 and 433 are slightly more complex mechanically than other date systems. Yet they can be easily dismantled and reassembled and they cannot be thrown out of adjustment. These are true “instantaneous change calendar mechanisms” meaning that if the hands are indexed properly during re-assembly, the date will snap over at midnight.
To effect the instantaneous date change at midnight, the release lever works in conjunction with its cam which is driven by the going train and which gradually stretches the prominent release spring. At the proper time, the cam releases the lever imparting an impulse to the calendar click which shifts the date-indicator instantaneously. The date-indicator is held in place by the date-jumper. The mechanism pre-dates the quickset date function but for setting purposes, the date can be advanced by turning the hands between 10:00 and midnight (22:00-24h) until the proper dates appears in the date window.
b. The Winding Mechanism
The watch can be wound by the stem or automatically via the oscillating weight . The winding rotor is somewhat unique. The outermost section of the oscillating mass is made of high density tungsten carbide. The center portion of the rotor is resilient and acts as a shock absorber. The rotor is ball bearing borne and the bearings are protected from shock as the core is elastically connected to the automatic winding bridge as the center of the oscillating mass contains a patented centering ring and a pressure spring. These require special attention on disassembly and assembly. A swing-over clutch breaks the contact between the crown wheel and ratchet wheel when the automatic winder comes into action, thus disconnecting the gear train from the keyless works. The ratchet wheel, which participles in both manual and automatic winding is made of beryllium-bronze to protect against wear. The reverse pawls and their supports are specially treated and should not be lubricated. The reversers and reduction gear ride in beryllium bronze bushings.
The barrel is a complete unit with a spring of a “practically unbreakable alloy” which is self-lubricating. The mainspring renders a nominal power-reserve of 42 hours. The mainspring barrel cover is marked “Ne pas ouvrir - Do not open." However, the barrel arbor is, of course, lubricated in the normal fashion; it too rides in two beryllium-bronze bushings which are expected to be wear resistant. Indeed, each element of the movement was designed relative to the greater stresses implied by the movement's higher frequency.
c. The Going Train
The going train has four jeweled wheels. The center pinion rides in beryllium-bronze bushings. When replacing the hands (sized: 90/150/19) it is necessary to apply pressure on the center wheel on the bridge side of the movement. The third wheel drives the sweep second hand and a beryllium bronze friction spring ensures smooth operation of the second hand by pressing lightly on the end of the seconds pinion. The seconds are driven indirectly. The fourth wheel, the traditional carrier of the seconds’ hand, has 100 teeth.
VIII. Increased Wear at Increased Oscillation Rates?
There are lubrication issues that are specific to the high-beat movements simply to keep the lubrication from being thrown off escape wheel teeth. In this regard, the historical significance of the El Primero 3019 PHC the first automatic chronograph movement should not be lost. Zenith and Movado were partners at the time the movement was produced. It lead to the El Primero 400/410 movement which was used not only by Zenith and Concord but also by Rolex in the Daytona Cosmograph. The high frequency El Primero is still in production, albeit with a hiatus wherafter production was revived in 1980.
This raises an interesting question because it has been suggested that the problem with the 36,000 bph movements was that the pallet arbors often wore out as a result of problems with lubrication, lubrication technology or perhaps materials. We have noted the pallet arbors were not lubricated in the Ultra-Chron although this is standard operating procedure for general overhaul and maintenance. And yet many unabused 36,000 bph Ultra-Chron's are still ticking with favorable accuracy. Obviously this could not have been universal since Zenith’s 36,000 bph El Primero continues to be used today. Favre-Leuba suggested that over its two years of testing, no abnormal wear was found in the fast beat movements. They suggested that as long as proper lubrication was maintained wear rates would remain comparable to the wear rate of slower movements. Although a fast beat movement may not need more frequent servicing than a slower beat movement, it will be less tolerant of lubrication failure due to aging, dissipation, etc. There was however a definite move to reduce the high frequency movements to 28,800. This appears to have ostensibly solved any alleged issues.
However, the 6641 released in 1972 appears arguably before the ETA 633.1, which is, of course based on the ETA 2824. These modified ETA movements were arguably used by Longines in 1976 well after the reduced frequency Longines 6641 and base ETA 2824 were introduced. Furthermore, Longines was clearly still innovative as late as 1975, with its patented co-axial barrel system, for the caliber L890 series movement.
While Longines, GP and Favre-Leuba pioneered the high beat movements, the oscillation rate of 28,800 bph became the industry standard around 1972. It seems a reasonable conclusion that in an attempt to stabilize the movement from outside forces, the idea sprung up to simply double the oscillating frequency, hence 18,000 bph became 36,000 bph. Perhaps it was the result of wear that the engineers decided to settle back to the 28,800 bph that we know today as the standard. Surely something happened because the 36,000 bph movements pre-date the 28,800 bph movements. It is therefore questionable that lubrication was the sole issue. Not long after its introduction, Longines released the Ultra-Quartz and then the Quartz Crisis of the 1970’s began.
IX. Conclusion-- many unanswered questions
We have discovered many of the nuances and secrets of this caliber. But the Longines caliber 430 series was short-lived. Introduced in 1967 it was phased out by no later than 1975. As early as 1972, the Ultra-Chron was optimized as the Longines 6641 series. This was the same movement but which vibrated at a reduced 28,800 bph. This was the second generation of the original movement described as a "robust modern design." The second generation, like its predecessor was said to offer remarkable stability of rate, as well. Other than the beat rate, the technical specifications were otherwise unchanged. While the limitations of lubricants may have been a factor favoring the 28,800 bph and militating against the 36,000 bph, it is surprising to note that the 6641 series called for a "filmogenic" method of lubrication rather than the discrete pivot points lubrication specified for the 430 and for most modern automatic movements.
And so, unfortunately, more questions are perhaps raised than answered herein. For example:
Why was there a transition from 36,000bph to 28,800bph which affected the entire industry leading to the standard we know today? Were there serious wear or lubrication issues as suggested by some? Was it simply the best compromise?
Perhaps if answered the horological world would have a more complete picture of one of the finest and most accurate mechanical movements of the last 300 years, from one of the most prolific, innovative and talented watch companies in Switzerland.
N.B.: Revised, corrected and spell-checked 3-01-07; this document constitutes a "draft" and is subject to revision. The information contained herein is believed to be accurate and every attempt has been made (and is on-going) to ensure its accuracy however, no warranties are made. Any translations from the original French texts (if any) are those of the author alone and are not official. [The preceding is an advance reader/synopsis of a more detailed article which will appear in the Bulletin of the National Association of Watch & Clock Collectors in December 2007].
Y como algunos preferiréis la página en cuestión, pues ahí va también, tiene enlaces de lo más interesante http://montresuisses.blogspot.com/20...-calibers.html