MB&F’s iconic Legacy Machine now incorporates one of the most traditional complications in the mechanical watch making: the Perpetual Calendar. Equipped with a visually stunning in-house movement, this high horology timepiece was created in association with independent Irish watchmaker Stephen McDonnell.
The LM Perpetual project began three years ago with a meeting between Maximilian Büsser and Northern Irish watchmaker Stephen McDonnell. McDonnell had been a long-time Friend of the brand and played an instrumental role in the realisation of MB&F’s very first timepiece, Horological Machine No.1. As Büsser was thinking of developing a perpetual calendar for the fourth watch in the Legacy Machine collection, McDonnell replied that he had an idea for a perpetual calendar that addresses many of the drawbacks associated with conventional examples.
Developed from the ground up to eliminate the drawbacks of conventional perpetual calendars, the new complication looks sensational and can be fully appreciated dial-side is just one of the many benefits offered by the new movement, controlled by a mechanical processor (patent pending).
LM Perpetual features a fully integrated 581-component calibre − no module, no base movement − with a revolutionary new system for calculating the number of days in each month. And it holistically reinterprets the aesthetics of the perpetual calendar by placing the full complication on dial-free display underneath a spectacular suspended balance.
Traditional perpetual calendars have a few drawbacks: dates can skip; they are relatively easy to damage if adjusted while the date is changing; and the complications are usually compromises of modules powered by base movements. The fully integrated, purpose-built movement of Legacy Machine Perpetual has been designed from scratch for trouble-free use: no more skipping dates or jamming gears, and the adjuster pushers automatically deactivate when the calendar changes.
Traditional perpetual calendar mechanisms use a 31-day month as the default and basically “delete” superfluous dates for the months with fewer days – by fast-forwarding through the redundant dates during changeover. A traditional perpetual calendar changing from February 28 to March 1 scrolls quickly through the 29th, 30th and 31st to arrive at the 1st.
LM Perpetual turns the traditional perpetual calendar system on its head by using a “mechanical processor” instead of the conventional space-consuming grand levier (big lever) system architecture. The mechanical processor utilises a default 28-day month and adds extra days as required. This means that each month always has the exact number of days required; there is no fast-forwarding or skipping redundant days. And while the leap year can only be set on traditional perpetual calendars by scrolling through up to 47 months, LM Perpetual has a dedicated quickset pusher to adjust the year.
With its open dial revealing the full complication and suspended balance, it’s the harmonious mechanical beauty of LM Perpetual that really steals the show. And in an interesting technical twist, that eye-catching balance hovering on high is connected to the escapement on the back of the movement by what is likely to be the world’s longest balance staff.
Using an innovative system developed especially for Legacy Machine Perpetual, the subdials appear to “float” above the movement with no visible attachments. The skeletonised subdials rest on hidden studs, which is technically impossible with traditional perpetual calendar mechanisms because they would block the movement of the grand levier.
Taking a clockwise tour of the dial, at 12 o’clock we see the hours and minutes nestled between the elegant arches of the balance; day of the week at 3 o’clock, power reserve indicator at 4 o’clock, month at 6 o’clock, retrograde leap year indicator at 7 o’clock, and date at 9 o’clock.
Legacy Machine Perpetual launches with a limited edition of 25 pieces in 18K red gold and 25 pieces in platinum 950.
Fully integrated perpetual calendar developed for MB&F by Stephen McDonnell, featuring dial-side complication and mechanical processor system architecture with inbuilt safety mechanism. Manual winding with double mainspring barrels. Bespoke 14mm balance wheel with traditional regulating screws visible on top of the movement. Superlative hand finishing throughout respecting 19 th century style; internal bevel angles highlighting hand craft; polished bevels; Geneva waves; hand-made engravings.
Power reserve: 72 hours
Balance frequency: 18,000bph/ 2.5Hz
Number of components: 581
Number of jewels: 41
Hours, minutes, day, date, month, retrograde leap year and power reserve indicators
Material: launch editions in 18K5N+ red gold or platinum 950
Dimensions: 44 mm x 17.5 mm
Number of components: 69 components
Water resistance: 30 m / 90′ / 3 atm
Sapphire crystals: Sapphire crystals on top and display back treated with anti-reflective coating on both faces
Black or dark brown hand-stitched alligator strap with gold / platinum folding buckle matching case material
Biography Stephen McDonnell
Stephen McDonnell was born in Belfast, Northern Ireland in 1972. He has been interested in watchmaking ever since he remembers, tinkering and “repairing” his grandfather’s clocks as a precocious four-year-old. While growing up, McDonnell’s passion − which he describes more as an addiction − never abated, however as watchmaking was not a particularly well-known career path in Northern Ireland, he always thought that it would remain a hobby while he worked in another field.
After completing a degree in theology at Oxford University, McDonnell returned to Belfast and gradually fell into repairing clocks for a number of watch and clock shops. This led to the realisation that watchmaking might well be a career after all. After completing a one-week Rolex course − until then his experience had been virtually exclusively with clocks − McDonnell moved to Neuchâtel, Switzerland in 2001 to do a six-month course at WOSTEP (Watchmakers of Switzerland Training and Educational Program). Upon completion, he was offered an instructor position at WOSTEP, which he held until 2007 when he decided to set up as an independent watchmaker.
McDonnell became an accomplished, though self-taught, movement designer, which provided him with a very rare skill set as watch constructors rarely have hands-on practical watch experience.
McDonnell moved back to Belfast with his wife and two children in 2014. He now works from his own comprehensively-equipped workshop, enabling him to make anything he needs for prototyping. An absolute horological perfectionist, McDonnell likes to control all aspects of the development process from conception through to 3D design, construction, the creation of technical plans, and prototyping.