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Up Close With MB&F's Revolutionary Legacy Perpetual At SIHH

This year, the SIHH invited nine independent watchmakers to the exclusive luxury exhibition. Naturally, the incredible MB&F was one of them. This was great because it gave us a chance to have an up-close look at the brand's newest Legacy Machine — the Legacy Perpetual Calendar.


Photo courtesy of R. Naas, www.ATimelyPerspective.com

This represents the brand's first complicated timepiece. As such, they had to do it differently, and so introduced a totally unique method of tracking the days and in displaying the perpetual calendar in 3D glory on the dial side of the watch architecture.

The easiest explanation comes from veteran watch journalist, Roberta Naas, who explains it on her site, www.ATimelyPerspective.com: "The perpetual calendar function offers day, date, month and other calendar information, but does it differently than anything else before it," she wrote.


In most perpetual calendars, no matter whether a month has 28, 29, 30, or 31 days in it, the date is determined by first starting with a 31-day date wheel and then the mechanics of the watch — via deeper or shallower wheel notches on the date disc — skip (or subtract) the correct number of days accordingly with each month to show the date. Essentially, to delete the extra, unwanted days in some months, the perpetual calendar must quickly scroll through the teeth to arrive at the first — often resulting in jammed gears or skipped dates.


The MB&F Legacy Machine Perpetual Calendar does the opposite of the traditional date counting and offers a revolutionary way of counting the number of days in a month. Instead of starting with 31 days and subtracting days each month, the default month for this watch is 28 days, and extra teeth in the wheel are added for the months with more than 28 days. This means that there is no need for the mechanics to skip through or fast-forward dates. Instead, extra days are added when needed via a patent-pending mechanical processor. This eliminates the typical “grand Levier” system for driving the dates in perpetual calendars, and the mechanical processor does the work. This replacement makes it possible for the wearer to change time or date at will without worrying about breakage (traditional grand lever calendars cannot be changed or reset between certain hours without resulting in damage)."

The idea is the brainchild of Northern Ireland watchmaker Stephen McDonnell, who had previously worked with MB&F to help with the development of the brand's HM1 movement. When McDonnell shared his unique concept with MB&F founder, Max Busser, it was an immediate "must do." The watch features the calendar, skeletonized subdials and suspended balance on the dial side — and appears to “float” above the 581-part movement in full glory. Just 25 pieces will be made in 950 platinum and 25 in 18-karat 5N rose gold. We invite you in to see the other horological machines from MB&F that are in our store at any time.