Jaeger-LeCoultre Caliber 846 – Technical Overview from Document 1150_JLC

The Jaeger-LeCoultre Caliber 846 is a manual-winding mechanical movement from the 1970s, closely related to the Caliber 846-1. Document 1150_JLC provides an in-depth technical description, including detailed exploded views, component specifications, and servicing guidelines. This caliber is noted for its compact dimensions, reliability, and the elegant small seconds complication.

Technical Specifications

• Type: Manual-winding

• Functions: Hours, minutes, small seconds at 6 o’clock

• Jewels: 17

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

• Power Reserve: Approximately 40 hours

• Diameter: Approximately 23.3 mm

• Height: Approximately 3.9 mm

The movement’s slim profile allows for integration into thin watch cases while maintaining high precision and durability.

Movement Features

The document details the following key characteristics of Caliber 846:

• Small seconds display driven by the fourth wheel pinion, positioned at 6 o’clock for classic dial symmetry

• Robust gear train and barrel assembly designed for smooth power delivery

• Shock protection system on the balance wheel, including fine adjustment via index regulator

• Efficient manual winding mechanism with reliable crown action for both winding and setting

Servicing Guidelines

• Lubrication: Critical lubrication points include escape wheel pivots, balance staff, and gear train pivots, using high-quality synthetic oils; light grease is applied to barrel arbors and winding gears

• Regulation: Aim for a stable amplitude of 260°–280° (dial-up) and minimize beat error to below 0.7 ms

• Small seconds mechanism: Ensure proper engagement and minimal backlash between fourth wheel and small seconds pinion to prevent hand jitter

• Mainspring inspection: Check for fatigue and replace if necessary to maintain consistent power delivery

Applications

Caliber 846 was used predominantly in:

• Elegant Jaeger-LeCoultre manual-wind dress watches of the 1970s

• Models featuring classic design cues, including small seconds dials and minimalist hour markers

• Cases made from stainless steel or precious metals, generally ranging from 34 to 36 mm in diameter

• Timepieces targeting buyers appreciating mechanical simplicity paired with refined aesthetics

Conclusion

The Jaeger-LeCoultre Caliber 846, as presented in document 1150_JLC, exemplifies JLC’s craftsmanship in producing reliable, compact manual movements with traditional complications like small seconds. Its balance of slimness, precision, and ease of servicing makes it a favored choice among collectors and watchmakers specializing in vintage mechanical wristwatches. The movement stands as a testament to JLC’s commitment to enduring mechanical excellence.