New Release: MB&F LM Perpetual EVO Blue

Since 2005, MB&F has been making horological waves for their wild Horological Machines (HM). In 2011, the ‘more normal’. round-cased Legacy Machine 1 (LM1) launched the Legacy Machine collection.

While not quite as disruptive as the HMs, the LMs were still very eye-catching and full of ground-breaking watchmaking, but the complications were visually stunning reinterpretations of the past rather than truly revolutionary horology.

That all changed in 2015 with the launch of LM Perpetual. Irish watchmaker and movement designer extraordinaire Stephen McDonnell reinvented the previously breakage-prone perpetual calendar complication and LM Perpetual transformed MB&F from a serious design-led boutique brand into a very serious horological brand.

MB&F LM Perpetual EVO Blue

After the initial classic versions of the LM Perpetual, in 2020, MB&F released the EVO editions, which had a more casual look and were more suitable for daily wear and active lifestyles. The EVO editions feature a FlexRing movement shock absorber, 80-meter water resistance, screw-down crown, rubber strap, Super-LumiNova, and redesigned ergonomic cases.

The first three launch editions had zirconium cases, with the options of orange, dark blue or black dial plates.

In 2021 MB&F launched the LM Perpetual EVO with a grade 5 titanium case and green dial plate.

MB&F LM Perpetual EVO Blue

Now in 2024 MB&F has retired the Titanium Green and introduced LM Perpetual EVO BLUE, in titanium with light blue dial plate.



From the press release:

Although the 44mm diameter is unchanged from its 2015 iteration, the new EVO case design features a no-bezel construction, with the domed sapphire crystal fused directly to the case.

MB&F LM Perpetual EVO Blue

The increased openness of this design highlights the equilibrium between the legibility of LM Perpetual EVO’s calendar indications and the cinematic play of the engine components — surmounted by the iconic MB&F hovering balance wheel.

This expansive new presentation of the LM Perpetual Engine was no simple design reconfiguration. New geometries for the sapphire crystal had to be calculated, achieving the mechanically opposing aims of maintaining structural strength and decreasing its height-to-diameter ratio. Freeing LM Perpetual EVO from the bezel also necessitated the use of a sophisticated thermal bonding system between the sapphire crystal and the case.

MB&F LM Perpetual EVO Blue

The previously circular pushers for adjusting the perpetual calendar have been enlarged into double-sprung oblong actuators, boosting the tactile comfort and ease of adjustment. The LM Perpetual EVO is rated at 80m of water resistance, enabled by its screw-down crown.

A small, but essential, detail of implementing a screw-down crown is the débrayage of the winding stem, disengaging the crown from the winding mechanism when it is pushed in and tightened, which eliminates the chance of manually over-winding the mainspring barrel.

MB&F LM Perpetual EVO Blue

An additional new element of the LM Perpetual EVO is the FlexRing: an annular dampener fitted between case and movement, providing shock protection along the vertical and lateral axes. Machined from a single block of stainless steel, the dampener imparts exceptional robustness to the perpetual calendar, a function that is associated with classicism and elegance, but is arguably the most pragmatic and utilitarian of all the high complications.



When Stephen McDonnell set out to redesign the perpetual calendar for MB&F, he proposed a system that rethought the entire mechanical basis of the complication. The LM Perpetual uses a “mechanical processor” consisting of a series of superimposed disks.

This revolutionary processor takes the default number of days in the month at 28 — because, logically, all months have at least 28 days — and then adds the extra days as required by each individual month.

This ensures that each month has exactly the right number of days, and removes the possibility of the date jumping incorrectly. An inbuilt safety feature disconnects the quickset pushers during the date changeover, so that even if the pushers are accidentally actuated whilst the date is changing, there is no risk of damage to the movement.

MB&F LM Perpetual EVO Blue

In design, in technique, in spirit, Legacy Machine Perpetual EVO has been an evolution of your story with MB&F.

The LM Perpetual EVO is not a watch for sports. It is a watch for life.

MB&F LM Perpetual EVO Blue

Calendric computation

Conventional perpetual calendars are generally modules comprising the complication, which is fitted on top of an existing movement. The calendar indications are synchronised by a long lever running across the top of the complication and passing through the centre. As the date changes, this long lever transmits information to the appropriate components and mechanisms by moving backwards and forwards.

This traditional system, while beautiful in its interplay of levers and components, is also extremely unwieldy, restricting movement construction in several key ways that would make something like Legacy Machine Perpetual a mechanical impossibility.

MB&F LM Perpetual EVO Blue

Created by Stephen McDonnell and premiered in 2015, the LM Perpetual Engine was — and still is — one of the most innovative perpetual calendar systems to exist in modern watchmaking.

In the traditional system, perpetual calendars assume that, by default, all months have 31 days. At the end of months with fewer than 31 days, the mechanism quickly skips through the superfluous dates before arriving at the 1st of the new month.

Any manipulation or adjustment of the date during the changeover can result in damage to the mechanism, requiring expensive repairs by the manufacturer. The dates can also jump or skip during changeover, negating the whole point of the perpetual calendar in the first place, which is not requiring adjustment for years. Or decades.



Legacy Machine Perpetual uses a “mechanical processor” consisting of a series of superimposed disks. This revolutionary processor takes the default number of days in the month at 28 – because, logically, all months have at least 28 days – and then adds the extra days as required by each individual month. This ensures that each month has exactly the right number of days. There is no “skipping over” redundant days, so there is no possibility of the date jumping incorrectly.

MB&F LM Perpetual EVO Blue

Using a planetary cam, the mechanical processor also enables quick-setting of the year so that it displays correctly in the four-year leap year cycle, whereas traditional perpetual calendar mechanisms require the user to scroll through up to 47 months to arrive at the right month and year.

The mechanical processor also enables an inbuilt safety feature that disconnects the quick-set pushers during the date changeover, eliminating any risk of damage while the date is changing.

In 2015, Legacy Machine Perpetual premiered the world’s longest balance wheel pinion, connecting the hovering balance to the escapement on the back of the engine. This technical feat has since been showcased elsewhere in the MB&F collection, namely the Legacy Machine Split Escapement.

MB&F LM Perpetual EVO Blue

I highly recommend watching the two videos below from talks respectively by Maximilian Büsser and Stephen McDonnell at Dubai Watch Week 2023. Note skip the blank first couple of minutes.

Further reading: Legacy Machine Perpetual Catapults MB&F Into The Big League: Here’s Why

For more information, please visit

Quick Facts MB&F Legacy Machine Perpetual Blue
Functions: hours, minutes; perpetual calendar with day, date, month, retrograde leap year, power reserve indicator
Case: grade 5 titanium. Crew-in crown
Dimensions: 44 mm diameter x 17.5 mm high
Movement: manually wound, integrated perpetual calendar with complication on top of base plate, mechanical processor system architecture with inbuilt safety mechanism, excellent hand finishing
Power reserve: 72 hours
Water resistance: 80-meters
Strap and buckle: rubber strap with titanium folding buckle
Price: CHF 168,000 / USD 198,000 / EUR 176,000 + VAT

You might also enjoy:

Presenting ‘Making Time’: The Greatest Watch Film Ever Made (In My Extremely Biased Opinion)

MB&F HM11 Architect: A Slow Motion Fidget Spinner for the Wrist

M.A.D.1 Red Owner’s Review: The Spirit of Something Greater and the Most Affordable Horological Machine by Maximilian Büsser (Plus Videos)

MB&F LM Sequential EVO Dual Chronograph: An Ingenious Application of a Simple Idea (That Nobody had Thought of Before)

A Must-See for Everyone! Horological Neophytes, All Industry Professionals (including Marketing/Communication/Admin), and Press, this talk by Stephen McDonnell is For You – Don’t Miss This!

1 reply

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *