MB&F Legacy Machine Perpetual features a visually stunning in-house movement – developed from the ground up to eliminate the drawbacks of conventional perpetual calendars. 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.
The perpetual calendar is one of the great traditional complications, calculating the apparently random complexity of the varying numbers of days in each month − including the 29 days in February during leap years. But traditional perpetual calendars do 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 Legacy Machine 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. MB&F Legacy Machine Perpetual takes advantage of its fully integrated movement to place the perpetual calendar mechanism on top of the movement main plate so that it can be appreciated from above. Legibility is often an issue with perpetual calendars due to the sheer number of indications, and LM Perpetual addresses this by using skeletonised subdials (except for the time indication) that appear to float above the complication with no apparent support from below.
In yet another innovation, Legacy Machine Perpetual uses what is likely to be the world’s longest balance wheel pinion to connect that elegantly suspended balance, hovering above the top of the movement, to the escapement on the back of the movement. Ensuring the practicality and reliability of this approach was essential before any other development work began. While the view through the display back is animated by the escapement, it’s the spectacular hand-finishing of the bridges and plates that really captivates the eye.
MB&F 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 18K 5N+ 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 on top and display back treated with anti-reflective coating on both faces
Strap & buckle
Black or dark brown hand-stitched alligator strap with gold / platinum folding buckle matching case material