#LONGINES SERIAL NUMBERS AFTER 1969 HOW TO#
#LONGINES SERIAL NUMBERS AFTER 1969 SERIAL NUMBER#
#LONGINES SERIAL NUMBERS AFTER 1969 MANUAL#

#LONGINES SERIAL NUMBERS AFTER 1969 SERIAL NUMBER#

For ease of reference, we have compiled all the serial number references we could find in one convenient place, and will add additional serial number tables as we can.

#LONGINES SERIAL NUMBERS AFTER 1969 HOW TO#

Many of you are curious how to tell the manufacturing date of your watch from the watch serial number located on the movement, or sometimes case. As usual some of it may be incorrect and I would value any corrections or further information you could provide.SERIAL NUMBERS TO MANUFACTURE DATE REFERENCE GUIDE this information was gleaned from various Internet sources. I would love to see other examples of the Ultra-Chron or any other high-beat watches, so please share them here. The features that attracted me to this watch are the radially brushed dial (measuring 29mm), the faceted polished hour markers and silver baton hands, the large easily read date display, the slim-line case and the ‘gliding’ second hand. I would appreciate if anyone could shed some light on why this occurred and what year of manufacture this might represent. This example has the serial number 50,790,282.

There was an anomaly in numbering for a period, probably in 1969, when “50 million” numbers were used. The Ultra-Chron’s released in 1967 had serial numbers in the 13 million range and in 1968 the 14 million range. As with Omega, and many other companies, movement serial numbers can be used to determine the approximate year of manufacture. It is difficult to precisely date this particular watch. The high-beat escapement is dry-lubricated with molybdenum bisulphide. The fourth wheel has 100 teeth and a pinion with 7 leaves. The movement was made in-house by Longines, but utilized the Clinergic-21 Swiss-anchor escapement, so named because of the 21 teeth of the steel escape wheel. The escapement features a screw-less, three-spoke, glucydur balance with a KIF-ultraflex shock absorber, fine regulation by an eccentric screw and a flat Nivarox, non-magnetic, self-compensating hairspring. The centre of the rotor is pieced with the flying hourglass symbol of Longines and acts as a shock absorber. The central automatic bi-directional, bi-metallic winding rotor is mounted on ball bearings and has a heavy tungsten-carbide perimeter. The movement is engraved with “adjusted in 4 positions and temperature” as well as with the escapement speed of “36000”. It has 25 jewels and is 25.6 x 4.80mm in size (note the Cal. 431 movement has a central second hand (the best way to view the high-frequency movement in action as the hand glides around the dial) and a non-quick-set date at 3 o’clock which jumps instantaneously at midnight. This single-piece construction adds to the water resistance of the watch. The case is a single piece and the movement, dial and crystal is literally popped out (quite loudly) by removing the crown and stem and pumping air into the case. The Longines Ultra-Chron shown here has a case measuring 34 x 9mm, but the tapered back allows the watch to sit flat on the wrist and appear quite slim. Only a handful of these watches were released with COSC chronometer certification, but the non-certified watches performed well within COSC specifications. That translates to an accuracy of better than 2 seconds per day. Guaranteed accurate to within a minute a month”. Longines advertising from the period spruiked “The world’s most accurate watch.

6651 and Cal 6652 models beat at a slower 28,800vph, but also had “Ultra-Chron” on the dial.

#LONGINES SERIAL NUMBERS AFTER 1969 MANUAL#

433 (date only) and some interesting manual wind movements which featured a hacking second hand which would stop when it reached the 12 mark (the Cal. The early GP watches had a relatively short power reserve and many consider that Longines was the first company to release a practical hi-beat watch.Ī number of movements were used in the Ultra-Chron over the nine years of production. The mainspring was also thicker and larger to provide adequate power. To achieve the faster rate, 21 teeth were used in the escape wheel instead of the usual 15. Most high-beat watches oscillate at 36,000vph, although 28,800vph was also considered a high rate at the time. A number of companies produced such watches, although Girard-Perregaux is said to have been the first to bring these to market in 1965 (showcased at the Basel fair of 1966), with Longines being the second in 1967. High-beat watches were intended to provide greater consistency of rate in different positions and be more isochronous.

Longines went on to produce several variations of the Ultra-Chron, including different case shapes, between 19. The Longines Ultra-Chron automatic high-beat-rate wristwatch was introduced in 1967 to mark the 100 year anniversary of the company which was founded in 1867.

Longines serial numbers after 1969