Jaeger-LeCoultre Caliber 845 – Technical Overview from Document 1148_JLC

The Jaeger-LeCoultre Caliber 845 is a manual-winding mechanical movement produced in the 1970s, developed as part of JLC’s family of slim, reliable calibers for elegant dress watches. Document 1148_JLC provides a comprehensive technical overview including component layouts, servicing details, and lubrication guidelines. The caliber is notable for its small seconds complication, offering a classic and refined dial design.

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: ~23.3 mm

• Height: ~3.9 mm

This compact size and relatively low profile make the Caliber 845 ideal for slim watches that balance traditional aesthetics with precise mechanical performance.

Movement Architecture and Features

According to document 1148_JLC, the Caliber 845’s key features include:

• Small seconds display positioned at 6 o’clock, driven by the fourth wheel and pinion

• Manual winding barrel with efficient gear train ensuring steady power delivery

• Shock-protected balance wheel, equipped with a fine index regulator for accurate rate adjustment

• Simplified motion works optimized for small seconds function and slim movement height

The movement’s bridge layout is designed for ease of servicing, with clearly defined components and minimal overlap.

Servicing Notes

• Lubrication: Apply fine oils sparingly to the escape wheel, pallet fork, and balance pivots; light grease on barrel arbor and winding gears

• Regulation: Target amplitude is 250°–280° (dial-up), with beat error under 0.7 ms

• Small seconds: Ensure the fourth wheel pinion and sub-seconds wheel are properly seated to prevent hand stutter or slipping

• Mainspring inspection: Check for fatigue or deformation, which can affect power reserve and amplitude

Applications

The Caliber 845 was typically employed in:

• Jaeger-LeCoultre dress watches from the 1970s with classic styling

• Models emphasizing traditional dial layouts, often featuring applied indices and dauphine hands

• Cases crafted in stainless steel or precious metals, generally between 34–36 mm in diameter

• Watches targeting buyers who appreciate the elegance of small seconds over central seconds for a vintage look

Conclusion

The Jaeger-LeCoultre Caliber 845, as detailed in document 1148_JLC, is a refined, serviceable manual-winding movement that combines precision, traditional aesthetics, and a slim form factor. Its small seconds complication and robust construction make it a desirable caliber for vintage watch collectors and professional watchmakers working on JLC’s classic timepieces. The movement embodies the brand’s dedication to mechanical excellence within elegant design constraints.