MB&F Reinvent The Perpetual Calendar In Stainless Steel

MB&F Reinvent The Perpetual Calendar In Stainless Steel

The MB&F Legacy Machine has been crafted in a multitude of precious metals since its inception in 2015 – the latest version will be crafted in Stainless Steel.

The LM Perpetual Stainless Steel, features a rich salmon-coloured plate, which is a first for MB&F. The new edition also inherits the ergonomic corrector pushers first seen on the LM Perpetual EVO editions. It 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.

Using an innovative system developed especially for Legacy Machine Perpetual, the sub-dials 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.

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. 

The Legacy Machine Perpetual won the Best Calendar Watch Prize at the GPHG (Grand Prix d’Horlogerie de Genève) in 2016.

Technical Specifications:

Legacy Machine Perpetual is available:

– in platinum 950 with blue face (limited to 25 pieces);
– in 18k red gold with grey face (limited to 25 pieces);
– in 18k white gold with purple face (limited to 25 pieces);
– in 18k white gold with dark grey face;
– in grade 5 titanium with green face (limited to 50 pieces);
– in 18k yellow gold with blue face (limited to 25 pieces);
– in palladium 950 with aquamarine face (limited to 25 pieces);
– in stainless steel with salmon face.


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 14 mm balance wheel with traditional regulating screws visible on top of the movement. Superlative hand finishing throughout respecting 19th 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: 18k 5N+ red gold, 18k white gold, 18k 3N yellow gold, platinum 950, grade 5 titanium, palladium 950 or stainless steel.
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.

Strap & buckle

Black, grey, brown or blue hand-stitched alligator strap with gold / platinum / titanium or stainless steel folding buckle matching case material.


LM Perpetual Stainless Steel is CHF 164,000 + VAT (USD 180,000 / EUR 172,000 + VAT)

For more information please visit MB&F

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