Jaeger-LeCoultre Caliber 620 – Technical Overview from Document 1130_JLC

The Jaeger-LeCoultre Caliber 620 is a classic manual-winding mechanical movement celebrated for its precision, durability, and traditional craftsmanship. Document 1130_JLC delivers a detailed technical exposition covering the caliber’s architecture, specifications, and maintenance requirements.

Technical Specifications

• Type: Manual-winding

• Functions: Hours, minutes, small seconds

• Jewels: 17

• Frequency: 18,000 vibrations per hour (2.5 Hz)

• Power Reserve: Approximately 40 hours

• Diameter: Approximately 27.0 mm

• Height: Approximately 3.5 mm

This caliber’s slim dimensions make it ideal for refined dress watches with a classic aesthetic.

Movement Architecture and Features

Based on document 1130_JLC, key features of Caliber 620 include:

• Small seconds subdial at 6 o’clock, powered by the fourth wheel

• Robust two-bridge construction offering stability and ease of service

• Efficient gear train and mainspring barrel designed for smooth power transmission

• Shock protection on the balance staff to enhance impact resistance

• Manual winding and setting mechanisms providing reliable and user-friendly operation

Servicing Notes

• Lubrication: Precise application of synthetic oils at escape wheel pivots, pallet fork jewels, and balance staff; light grease on barrel arbor and winding gears

• Regulation: Aim for amplitude between 250° and 280° and beat error below 0.7 ms for optimal accuracy

• Small seconds function: Ensure proper mesh and seating of the fourth wheel pinion and seconds hand to avoid stutter or excessive play

• Keyless works: Inspect regularly for wear to maintain smooth crown winding and setting action

Applications

Caliber 620 was used primarily in:

• Jaeger-LeCoultre dress watches from the mid-20th century

• Models featuring elegant small seconds displays and slim profiles

• Timepieces made in stainless steel or precious metals, typically sized between 34 and 36 mm

Conclusion

The Jaeger-LeCoultre Caliber 620, as detailed in document 1130_JLC, stands as a fine example of traditional Swiss manual-winding movement engineering. Its reliable construction, precise timekeeping, and refined design continue to make it a favored caliber among vintage collectors and professional watchmakers. It represents the enduring quality and mechanical excellence that characterize Jaeger-LeCoultre’s legacy.