Ball’s ‘Super Space Chief’, known for its miniature glowing gas lamps, has a magnetic resistance of 12,000A / m and should be a version without a soft iron cover.
Since the advent of watches and clocks, an important mission given to them is to be accurate. I once saw an article comparing Tudor Tudor ‘Ocean Prince’ and Omega Omega ‘Hippocampus’. The final result was that ‘Hippocampus’ won. The result is meaningless to me, but it is interesting that the text in the process, movement As for the results of polishing and other evaluation elements, the ‘Hippocampus’ movement is protected by a soft iron antimagnetic cover, so the travel time accuracy is greatly improved, and it should be higher.
The IWC ‘Engineer’ Earth Mission Edition with a soft iron protective cover on the movement has a magnetic resistance of 80,000 A / m.
Looking at clocks and magazines and websites, every reader and classmates mourn: My mechanical watch is very inaccurate or does not leave, ‘experts’ and table friends all have sympathy: it may be magnetized, go to the service station to degauss it. Such a reply, as if the computer is abnormal, there is a dose of herbal tea like ‘Restart and try’. The iron-containing parts in mechanical clocks are very sensitive to temperature and magnetic fields, especially the hairspring. The magnetic field can change its elastic modulus, deform under the action of the magnetic field, and generate additional stress. In severe cases, the magnetic field can cause the hairspring to stick and seriously affect the travel time. This is explained by experts. It can be proved that since the invention of mechanical timepieces, watchmakers have been working hard on hairspring materials, winding methods and movement protection structures, resulting in some hairsprings and movement assembly processes made of different materials. Become the exclusive magic weapon of each watch factory. From the ‘blue steel’ hairspring that was loved by watch fans in the past to the SPIRONAX non-metal hairspring launched by PP Patek Philippe, the structure has not jumped out from the masters of Baoji master 200 years ago, but today the material is greatly Progressed. But don’t forget that before the application of new materials to make the hairspring, the antimagnetic function of the watch has not been the focus, because the technology at the time was sufficient to meet daily needs, but water vapor and collision are the biggest enemy of clock accuracy.
Omega’s hippocampus series is currently a rare ‘professional’ watch that insists on installing a soft iron cover. It does not need to be sipped, as long as it is approved.
The earth we live in is a large magnetic field, but the earth’s magnetic field is very weak. The strongest magnetic field in household appliances is the hair dryer, which only generates about 350mG (milli-Gauss) intensity during operation. Generally, it is generated near high-voltage wires. The magnetic field strength is only a dozen mG. The antimagnetic material of general watches can reach 1000mG or more, which is enough to cope with daily living and working environment. Maybe only ‘engineers’ and explorers work under strong magnetic fields like radar or radio transmitting stations. Some well-known watch factories have introduced models with high-performance anti-magnetic, waterproof, and shock-resistant models, such as the ‘INGENIEUR Engineer’ series launched by IWC since 1955. In 1989, IWC applied the balance wheel assembly without iron and nickel materials. The engineer’s watch has undergone a diamagnetic test of 3,700,000 A / m, of which 5,000 have been named as ‘500,000 A / m engineer’ at the time of sale, so they can already withstand the magnetic field effects of CT magnetic resonance tomography imaging devices. In general, in addition to the ‘engineer’ who may be in the Jedi need anti-magnetic, pilots and military watches also do some anti-magnetic processing because of their special requirements. The watch with the name of ‘anti-magnetic’ must meet the DIN / ISO standard: stop for less than 30 seconds a day under the magnetic field strength of 4800A / m. With soft iron inner cover, it can resist magnetic field strength up to 80,000A / m. Rolex Milgauss Ref. 116400GV is a fully engraved version with a soft iron cover. Its Parachrom blue metal hairspring is more anti-magnetic in other movements, so it is completely a gimmick. In particular, the OMEGA lunar watch worn by the Apollo 11 astronaut in 1964 had a magnetically shielded cover, while the same ‘lunar watch’ now has a bottom.
Rolex Milgauss’ ‘green glass’ model 116400GV is an old version of its own, unique in style and can be owned.
Modern clocks and watches do not have a special anti-magnetic structure, even through the bottom of the watch, the daily wear is also accurate, without self-disturbance. For those with antimagnetic cover and soft iron plate under the dial, although it can reach 80,000A / m antimagnetic, such a high intensity magnetic field has nothing to do with our generation. A watch with a magnetic shield is not necessarily more accurate than a watch without a magnetic shield. High school physics textbooks teach us that objects that cut magnetic lines of force at high speeds will produce greater magnetic forces. If you see someone running with a watch next time, remember to yell: ‘Gump, don’t run!’