The updated version of the 1950s’ Rolex Milgauss is a hit among Rolex fans. Is this re-engineered classic, with its improved protection against magnetism, worth the wait? Writer Jens Koch and photographer Nik Schölzel find out in this watch test from our August 2008 issue.
Magnetic fields are invisible and do not greatly affect the human body. Maybe that’s why we don’t think about them very much, even though our high-tech world is full of them, generated by all sorts of devices, from motors to loudspeakers. Unlike the people who wear them, however, mechanical watches are extremely susceptible to magnetic fields. When parts of a watch’s movement become magnetized, its rate accuracy is disturbed, causing frustration for its owner.
Rolex addressed this problem in the 1950s with the introduction of its Oyster Perpetual Milgauss model. The name comes from the French mille Gauss, referring to the watch’s protection from magnetic fields up to 1,000 gauss (named after physicist Karl Friedrich Gauss, a gauss is a unit for measuring the strength of a magnetic field). This level of magnetism, which corresponds to 0.1 Tesla or 80,000 vph, is 100 times higher than that of a typical horseshoe magnet. It would take levels such as those found in an MRI scanner to affect the watch’s functioning. After devoting considerable time and effort to the development of the recent reissue of the Milgauss, Rolex introduced it at the Baselworld watch fair in 2007. Its inner case, made of ferromagnetic material, shields the movement from magnetic fields and consists of only two parts: a container and another cover tightly screwed to it. The container encloses the movement laterally and on the dial side, while the back seals the movement side. To ensure that the movement would be shielded as much as possible, the designers allowed for only a bare minimum of openings in the dial and case. This is why there is no aperture for a date display, for example. There are only the necessary small openings for the winding stem and for the axles that anchor the hands. There are also two tiny holes for the screws that hold the dial. Most other watches with magnetic protection have an inner case with three parts, with the parts layered on top of one another rather than threaded together.
Rolex didn’t stop there; its engineers were determined to make additional modifications to prevent even minute amounts of magnetism from leaking into the movement. The result of this initiative was the blue Parachrom hairspring that appears in the Rolex Milgauss as well as other Rolex models such as the Daytona, the new GMT-Master II and the Yacht-Master II. It is made of a niobium-zirconium alloy with an oxide coating and remains completely unaffected by magnetic fields. It is also supposed to withstand shocks better than conventional hairsprings. (Click here to read WatchTime’s 2010 visit to the Rolex manufacturing facility in Bienne, Switzerland and learn more about how these Rolex-exclusive springs are made.) Additionally, the pallet fork and escape wheel are made of amorphous nickel-phosphorous, which is completely antimagnetic. Opening the solid, screw-down caseback reveals the second caseback made of soft iron. It can be opened with the same special wrench used for the outer caseback. This caseback is marked with a “B” with an arrow above it — the symbol for magnetic flux density — as an indication of its special function.
(Interestingly, it is one of Rolex’s main competitors, Omega, that recently upped the ante on magnetism-resistant watches with the 2013 introduction of its Seamaster >1,500 Gauss, which uses even more antimagnetic materials in its movement; click here for more on that watch.)