On May 31st, MB&F released their 20th caliber in just 17 years of existence. This is a momentous moment for the brand and the friends that they work with to come up with some of the craziest ideas in watchmaking. As always the brand has delivered a watch that few would conceive without the creativity of those involved. The watch, the Legacy Machine Sequential Evo, is the first chronograph that MB&F has produced.

The LM Sequential EVO movement incorporates two column-wheel chronographs and a groundbreaking “Twinverter” binary switch, allowing multiple timing modes including split-second and lap timer modes – a combination never seen before in any chronograph. Naturally, MB&F is not going to produce a chronograph like all the other chronographs out there but a piece that can be described like all other MB&F watches and horological art. Conceived by one of the very earliest MB&F collaborators and Friends, Stephen McDonnell, LM Sequential EVO explodes the current limits of what we thought chronographs could do. Just like the 2015 Legacy Machine Perpetual, the last major Stephen McDonnell movement for MB&F, LM Sequential EVO involved a back-to-the-drawing board approach towards our most basic assumptions on chronograph construction.

The dial plate of LM Sequential EVO, available in atomic orange or coal black, features two chronograph displays. One has its seconds display at 9 o’clock and minutes display at 11 o’clock. The other has its seconds display at 3 o’clock and minutes display at 1 o’clock. Each of these chronograph displays can be started, stopped, and reset completely independently of each other, using the start/ stop and reset pushers on their respective sides of the case. These make up the four chronograph pushers you would usually associate with having two chronograph mechanisms in one watch. However, there is a fifth pusher, located at the 9 o’clock position: the “Twinverter”. This pusher is the secret that elevates the functionality of the LM Sequential EVO beyond any existing chronograph wristwatch. It controls both chronograph systems, operating as a binary switch that inverts the current start/stop status of each chronograph. This means that if both chronograph displays happen to be stopped (at zero position or otherwise), pressing the Twinverter will cause both of them to start simultaneously. If they are both running, the Twinverter makes them stop. If one is running and the other is stopped, the Twinverter stops the one that is running and starts the one that is stopped.

The four modes the chronograph can run on are described by the brand as follows:

• “Independent mode”: measure the duration of multiple events with separate starting points and end points, even when the events overlap in timing;

• “Simultaneous mode”: measure the individual durations of two events that start simultaneously, but have different end points;

• “Cumulative mode”: measure the individual cumulative durations of two discontinuous events;

• “Sequential mode (or lap mode)”: measure the individual sub-durations of a single continuous multiphase event, with provision for sub-durations that last over a minute.

From a technical perspective, Stephen McDonnell truly showed innovation by reimaging how the construction of a chronograph could work. Using two separate chronograph mechanisms linked to the same oscillator — an idea practically made for the Legacy Machine, with its central flying balance wheel — meant that timing errors due to tiny chronometric discrepancies between different timers would be eliminated. Stephen McDonnell continued to refine his vision of the ideal chronograph, reconfiguring the chronograph vertical clutch to sit within the main gear train in order to eliminate the infamous flutter of the chronograph seconds hand without the need for an amplitude-draining friction spring. He incorporated internally jewelled chronograph clutch shafts that would make amplitude fluctuation between the active and inactive modes of the chronograph a thing of history.

The crowning touch to Stephen McDonnell’s ideal chronograph, augmenting the role played by the combined starting lever in historical chronograph systems, is the Twinverter concept. The ability to toggle instantly between chronograph operating modes directly opens up this age-old complication to be used in a variety of situations in modern daily life. It is the programming logic gate of mechanical watchmaking, a system that could have been devised only by the creator of the mechanical processor at the heart of Legacy Machine Perpetual.

If you want to hear more from Stephen McDonnell and Max Busser about this piece, check out the release video live stream that they did where they dive further into the creation of the Sequential Evo.

Enjoy!