What it is
The Vacheron 1142 is Vacheron Constantin's haute-horlogerie chronograph caliber, derived from the famous Lemania 2310 architecture designed by Albert Piguet at Lemania in 1942. The 2310 became one of the most-celebrated chronograph designs in 20th-century watchmaking, badged as the Omega Cal. 321 in the Speedmaster (including the Apollo 11 Moonwatch), as the Patek Philippe CH 27 in countless Calatrava chronographs, and as the Vacheron 1141 / 1142 in haute-horlogerie Vacheron chronographs from the 1990s through the 2010s. The 1142 is the Vacheron-finished version: the same Lemania architecture, but rebuilt and refinished to Geneva Seal standard.
The Lemania 2310 lineage
The 2310 is one of the most important chronograph designs of the 20th century. Albert Piguet designed it at Lemania in 1942 — column-wheel switching, lateral clutch, 27 mm diameter, hand-wound, 2.5 Hz beat. Lemania supplied it as a base movement to anyone willing to buy: Omega badged it as Cal. 321 (1942-1968 Speedmasters, all the NASA-qualified Moonwatches); Patek badged it as CH 27 (Calatrava chronographs since the 1940s, including the famous ref. 130 and 1463); Vacheron began using it after acquiring the modernisation rights in the 1990s. Each brand finishes it to its own standard: Patek to Patek Seal, Vacheron to Geneva Seal, Omega to its industrial-tier finish. Mechanically all three are the same architecture; the difference is the bridges, anglage, and the brand's own modifications.
What Vacheron added
The 1142 is not a literal copy of the Lemania 2310 — Vacheron rebuilt it. Geneva Seal finishing: every functional surface anglaged and polished, Côtes de Genève on the bridges, perlage on the base plate, polished countersinks at every screw hole. Modern materials: updated mainspring alloy, modern lubricants. Vacheron-specific bridges with the Maltese-cross signature engraved on the chronograph bridge. 1141 is a sister variant in some references. The 1142 typically runs in larger Vacheron chronograph cases with display casebacks where the finishing is the visual centerpiece.
Where it appears
Vacheron Historiques Cornes de Vache 1955: the modern revival of the 1955 ref. 6087 chronograph, in steel, pink gold, and platinum. The Cornes de Vache is the canonical modern 1142-equipped Vacheron and one of the more-collected Vacheron chronographs of the 2010s-2020s. Vacheron Patrimony Traditionnelle Chronograph: dressy chronograph in pink and white gold. Vacheron Malte Chronograph (older references): tonneau-case Malte chronos. Various Quai de l'Île and limited-edition references: 1142 variants. By 2020 Vacheron had introduced its newer in-house chronograph caliber, the Cal. 5300 (with vertical clutch), but the 1142 remains in selected Cornes de Vache and high-finishing references.
How it compares
Versus Omega Cal. 321: same architecture, different finishing tier. Omega 321 is industrial-finish (rhodium-plated, simple Côtes de Genève); Vacheron 1142 is Geneva-Seal-finish (anglaged bridges, polished countersinks, Maltese-cross engraving). Versus Patek CH 27: similar finishing tier, both Geneva-Seal-class. Patek's CH 27 family was eventually replaced by the CH 29-535 PS in 2009; Vacheron stayed on the 1142 architecture longer, then moved to in-house Cal. 5300. Versus the modern Lange L951.1 Datograph: the Vacheron 1142 is the older architecture but with the haute-horlogerie pedigree of the Lemania 2310 lineage; the Lange L951.1 is the modern German equivalent, similarly finished but mechanically newer.
Service notes
Service for a 1142-equipped Vacheron runs USD 2,500-3,500 at Vacheron service (Geneva or authorised partners), with a 2-year warranty. Recommended interval: 5-7 years (chronograph mechanisms benefit from regular lubrication). Independent service is rare: parts are restricted, and the Geneva Seal certification is invalidated by non-authorised work. Vacheron service also re-engraves the Maltese cross on the chronograph bridge if it's been disturbed during disassembly. Turnaround is typically 4-8 weeks at the Geneva manufacture.