Seiko 4R35 / NH35 Parts

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Seiko 4R35 / NH35 Parts

The 4R35 and NH35 are automatic movements produced by Seiko Instruments Inc. (SII) and are nearly identical in functionality and design. The main differences lie in branding, calibration, and target audiences. Here's a detailed breakdown:

Similarities

  1. Mechanical Features:

    • Both are automatic movements with manual winding and hacking (second-hand stops when setting the time).
    • Identical technical specifications:
      • Beats per hour (BPH): 21,600 (6 ticks per second).
      • Power reserve: Approximately 41 hours.
      • Number of jewels: 24.
    • Both feature a date complication.
    • Share the same robust and reliable architecture.

  2. Design and Durability:

    • Both movements are built for long-term reliability and are widely used in affordable to mid-range watches.

  3. Functionality:

    • Both allow easy adjustment of the date via the crown.
    • Compatible with a wide range of watch cases.

Differences

Aspect 4R35 NH35
Branding Exclusively used in Seiko watches, branded "Seiko". Unbranded or marked "SII", designed for external manufacturers.
Purpose Reserved for Seiko’s in-house watch collections. Distributed to microbrands and independent watchmakers.
Calibration Calibrated by Seiko, often with tighter tolerances for their watches. Typically unregulated; calibration is handled by the manufacturer or watchmaker.
Availability Only available within Seiko watches; not sold separately. Widely available through aftermarket suppliers.
Rotor Decoration Branded "Seiko" with decorative finishes for certain models. Usually unbranded or marked "SII"; can be customized by brands.
Price Bundled with Seiko watches; not available for standalone purchase. Generally more affordable and sold as standalone movements.

Use Cases

  • 4R35:

    • Found in Seiko watches such as the Seiko 5 Sports series and other entry-level Seiko models.
    • Ideal for maintaining brand authenticity in Seiko watches.

  • NH35:

    • Widely used by microbrands, independent watchmakers, and hobbyists for custom watch designs.
    • A popular choice for aftermarket modifications due to its affordability and availability.

Which One Should You Choose?

  • Choose the 4R35 if:
    • You are buying or repairing an authentic Seiko watch and need an original replacement part.
  • Choose the NH35 if:
    • You are building or customizing a watch.
    • You are part of a microbrand looking for a reliable and versatile movement.

Conclusion

The 4R35 and NH35 are mechanically identical but cater to different audiences. The 4R35 is exclusive to Seiko watches, ensuring tighter calibration and brand authenticity, while the NH35 is widely available for independent watchmakers, offering versatility and affordability.