Jaeger-LeCoultre Caliber 864: Overview from Technical Document 1153_JLC

The Jaeger-LeCoultre Caliber 864 is a manual-winding mechanical movement engineered for small, ultra-thin timepieces, often designed for women’s wristwatches. Based on the detailed breakdown found in technical document 1153_JLC, this caliber continues Jaeger-LeCoultre’s tradition of combining mechanical finesse with miniature dimensions, offering precise timekeeping in an extremely compact format.

Technical Specifications

• Type: Manual-winding

• Functions: Hours and minutes (two-hand display)

• Jewels: Typically 17

• Frequency: 21,600 vibrations per hour (3 Hz)

• Power Reserve: Approximately 36–40 hours

• Diameter: ~15.3 mm

• Height: ~2.9 mm

These specifications are very close to the preceding Caliber 862, yet the 864 reflects slight evolutions in construction and parts design for improved serviceability and performance.

Movement Architecture and Features

The Caliber 864 is a time-only movement designed with simplicity and elegance in mind. Despite its reduced size, it maintains essential horological elements:

• No seconds hand, enabling a thinner architecture and clean dial aesthetics

• Small barrel with tightly wound mainspring, designed for compact energy delivery

• High-beat escapement relative to size, offering stable amplitude across the power reserve

• Minimalist gear train layout, enabling efficient torque transmission from barrel to hands

Document 1153_JLC presents detailed schematics of the baseplate and gear positions, making it especially helpful for disassembly and reassembly.

Visual Design and Finishing

Though compact and built for functionality, Caliber 864 still benefits from Jaeger-LeCoultre’s traditional finishing standards:

• Circular graining on the baseplate

• Fine brushing or light striping on bridges

• Polished screw heads and beveled edges, even at this scale

The movement is designed not for display through a caseback, but for lasting performance within refined, slim cases.

Applications in Watch Models

Caliber 864 has been used in:

• High-jewelry watches, particularly for women, where elegance and minimal dimensions are key

• Ultra-slim dress watches, where movement height had to remain under 3 mm

• Watches from the 1970s to 1990s, often branded under both Jaeger-LeCoultre and LeCoultre (for the U.S. market)

These watches typically feature gold, white gold, or platinum cases with minimalist two-hand dials and fine detailing.

Highlights from Technical Document 1153_JLC

Document 1153_JLC includes:

• Exploded diagrams showing all components, part numbers, and placement order

• Lubrication charts, specifying oil types and application points

• Keyless works and winding system details, including setting lever, yoke, and sliding pinion positions

• Balance and shock protection system layout, showing correct positioning for reassembly and adjustment

This documentation is especially important given the miniaturization—small misalignments can affect overall functionality.

Servicing Considerations

Because of its small scale, Caliber 864 demands careful handling during maintenance:

• Use of precision tools and high-magnification optics is essential

• Lubrication must be minimal and exact, particularly in the escapement and gear train

• Calendar-free architecture simplifies service, but great care is needed around delicate winding and setting parts

• Shock protection springs can be easily displaced due to their size, requiring skill to reinstall properly

Parts availability can be limited due to the age and specialized nature of the movement, often requiring sourcing from donor watches.

Conclusion

The Jaeger-LeCoultre Caliber 864, as outlined in technical document 1153_JLC, represents the brand’s ability to engineer mechanical excellence on a miniature scale. Designed for elegant, time-only watches, this caliber emphasizes discretion, slimness, and precision. It remains a fine example of JLC’s commitment to blending beauty and performance, particularly in the realm of ladies’ haute horlogerie.