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MB&F Debuts a New Legacy Machine: the LM Split Escapement

Among the many technical wonders MB&F built into its Legacy Machine Perpetual, which debuted two years ago (http://iwmagazine.com/news-and-now/20151103/mbf-introduces-legacy-machine-perpetual/), that watch’s seemingly anchor-free hovering balance wheel wasn’t among the most prominent. Naturally, aficionados focused on the LM Perpetual’s novel perpetual calendar with its entirely new system for calculating the number of days in each month.

Today MB&F introduces the return of that flying balance wheel, which the independent watchmaker now places front and center above a stunning frost-finished surface on the MB&F LM Split Escapement, a new limited edition Legacy Machine.

The MB&F LM Split Escapement, in profile

The MB&F LM Split-Escapement, in profile.

No longer set amid the LM Perpetual’s busy dial, the deconstructed balance wheel here takes the starring role and now serves as the watch’s namesake component.

Working again with watchmaker Stephen McDonnell, who developed the LM Perpetual’s fully integrated movement, and who also worked on MB&F’s Horological Machine No.1, MB&F showcases McDonnell’s unusual escapement by framing and suspending the 14mm-diameter balance high above the dial.

LM Split-Escapement with ruthenium darkened movement.

The balance’s solitary nature, seemingly unattached to the usual anchor and escape wheel, is the result of McDonnell’s horological slight of hand. He creates the illusion of an anchor-and-escape-wheel-free balance wheel by attaching both those components nearly twelve millimeters away on the opposite side of the case.

There, under sapphire glass, McDonnell gives the game away. He places the impulse jewel, anchor and escape wheel for all to see, at the end of what is likely the longest arbor used in a wristwatch (11.78mm long), and quite apart from the dial-side balance wheel. In doing so, he creates the Split Escapement.

The LM SE with yellow-gold frosting and movement finish

In lesser hands, the production of a long arbor that pokes through an entire movement could pose distortion problems. But McDonnell and the MB&F team address that possibility during a strict manufacturing and design process. They have fit the balance arbor at both ends with anti-shock jewel bearings. In addition, the bridge that holds the anchor and escape wheel is separately fixed for optimal fine adjustment.

The MB&F LM Split Escapement movement with blue PVD frosted surface.

As a result, MB&F assures us that the long arbor has no effect on the movement’s precision and power reserve. Carefully calculating the longer balance arbor’s higher mass (which could reduce the amount of energy ultimately transmitted to the oscillator) MB&F has installed two barrels in parallel, which allows up to 72 hours of optimal timekeeping. This confidence is displayed directly on the front of the watch in the form of a white lacquer power reserve dial.

Superlative finish

The technical work within this Legacy Machine is dressed, and enhanced, with a high horology finishing you’d expect from MB&F.

From the front, the Legacy Machine SE presents an evolved version of MB&F’s multi-dial LM series. Here, the new triple-dial design shows the time at 12 o’clock, the aforementioned power reserve indication at 4 o’clock and the date at 8 o’clock. The date can be quickly and easily adjusted thanks to a push-button on the side of the case, next to the date dial. The watch’s prominent arched balance bridge is polished and rounded, much like it was on the LM Perpetual Calendar, but here it holds sway above a spare, specially frosted surface that serves as the dial.

MB&F LM Split Escapement

MB&F has revived the frosted finish in a typically imaginative fashion. Generally associated with the early pocket watches that served as inspiration for the entire Legacy Machines concept, the hand-wrought frosting technique here is similar to the process MB&F used to decorate the LM 101 ‘Frost’ editions. Each plate is worked by hand with a wire brush to evenly distribute the indentations –the texture – that we identify as ‘frost.’ Then, each surface is treated with a colored PVD.

MB&F LM Split-Escapement with blue frosted finish

Rhodium-plated back view of the blue frosted LM Split-Escapement. Note the impulse jewel, anchor and escape wheel.

Not content to devise just one treatment color, MB&F offers four, each combining a set of dial and movement hues explained thusly:

- Blue frosted finish paired with rhodium-plated movement for the most classically elegant version;

- Ruthenium frosting with similarly darkened movement evoking new-millennial functionality and putting the focus on the white lacquer dials;

The MB&F LM Split Escapement movement, yellow gold PVD treatment.

- Red gold frosting and movement conveying warmth and accessibility, its subtle roseate sheen emphasizing the intense hue of the blued hands;

- Yellow-gold frosting and movement finish: the strongest aesthetic affinity with the era inspiring the Legacy Machine collection, an era that defined the precepts of modern watchmaking.

The micro-textured frosted dials on these watches are outstanding, particularly as used here as such a prominent sea of pure texture beautifully framing both the balance and the white lacquer dials. A collector who missed adding one of the earlier MB&F Legacy Machines to his or her wrist would do well to take a close look at this inaugural white gold LM Split Escapement.

Price: $79,000.

Technical Specifications: MB&F Legacy Machine Split Escapement

Four white gold launch editions limited to 18 pieces each, with a frosted dial plate in blue, ruthenium, red gold or yellow gold.


Developed for MB&F by Stephen McDonnell.
Split escapement with the balance wheel suspended above the dial and the anchor under the movement, 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 19th-century style; bevelled internal angles highlighting handcraft; polished bevels; Geneva waves; hand-made frost and engravings.

Power reserve: 72 hours
Balance frequency: 2.5Hz / 18,000bph
Number of components: 314
Number of jewels: 35

Functions & indications
Hours, minutes, date and power-reserve indicators.
Push-button next to the date dial for quick adjustment of the date.

Material: launch editions in white gold
Dimensions: 44mm x 17.5mm
Number of components: 49
Water resistance: 30 meters

Sapphire crystals
Sapphire crystals on top and display back treated with anti-reflective coating on both faces.

Strap & buckle

Black or brown hand-stitched alligator strap with white-gold folding buckle.

The MB&F LM Split Escapement movement with red gold frosted surface and movement plate

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