MB&F has just launched a new Legacy Machine Split Escapement with an interesting movement architecture that isolates the model’s characteristic flying balance wheel on the dial side while moving the anchor and the escape wheel beneath the dial and visible through the caseback.
The Legacy Machines line from the independent brand best known for its audacious designs are inspired by the timepieces made in the 18th and 19th century. On the new LM Split Escapement, the suspended wide balance wheel remains literally and metaphorically above everything else.
In a traditional movement, the escapement allows the stored energy of the mainspring to escape in a series of regular controlled impulses instead of unwinding all at once. In most cases, it consists of the balance assembly, anchor and escape wheel; these components tend to be placed as close to each other as possible to minimize external influences.
On the LM Split Escapement, the impulse jewel, anchor and escape wheel are visible through the transparent caseback while the 14 mm wide balance wheel is left to solely dominate the dial under a domed sapphire crystal. This is not the first time an escapement has been split. Stephen McDonnell, the Irish watchmaker who collaborated with the brand on this timepiece, used this first on the Legacy Machine Perpetual that was unveiled in 2015.
This unique arrangement uses an unusually long (11.78 mm to be precise) balance arbor, which runs through the center of the movement. Since a longer arbor increases the likelihood of disrupting influences on the oscillator it is fitted at both ends with anti-shock jewel bearings.
The bridge that holds the anchor and escape wheel is separately fixed for optimal fine adjustment. A longer balance arbour has a higher mass, which can be a drain on the power reserve, so the LM SE engine is driven by two barrels in parallel that provides the watch with 72 hours of energy when fully wound.
The triple-dial design of LM SE indicates the time at 12 o’clock, power reserve at 4 o’clock and the date at 8. The date can be quickly and easily adjusted thanks to a push-button on the side of the case, next to the date dial. Other design features are natural evolutions of those found in previous Legacy Machines, such as the arched balance bridge found in the LM Perpetual.
The dial features a micro-textured “frosted” finish seen on antique pocket watches of the 18th and 19th century. Seen previously on the LM 101 ‘Frost’ editions, it is achieved by manually burnishing a metal surface with a wire brush.
The LM Split Escapement is presented in four launch editions in a 44 mm white gold case, each limited to 18 pieces. One with a blue frosted finish paired with rhodium-plated movement, the second features Ruthenium frosting with similarly darkened movement, the third sports red gold frosting and movement finish and lastly, yellow-gold frosting and movement finish. The watch is paired with a black or brown hand-stitched alligator strap with white-gold folding buckle. Price? $79,000 + VAT.