Seiko 4R36 / NH36 Parts

 
Seiko 5 Sports SRPA49K1 Watch Parts 4R36 - 05M0 Dial, Bezel, Hands & Bracelet - Watch Plaza

Seiko 4R36 / NH36 Parts

The 4R36 and the NH36 movements are nearly identical in terms of functionality and specifications, as they are both produced by Seiko Instruments Inc. (SII). The main differences between them lie in branding, calibration, and intended use. Here’s a detailed breakdown:


Similarities

  1. Mechanical Features:

    • Both are automatic movements with manual winding and hacking (second-hand stop when setting the time).
    • They share identical specifications:
      • Beats per hour (BPH): 21,600 (6 ticks per second).
      • Power reserve: Approximately 41 hours.
      • Number of jewels: 24.
    • Both feature day and date complications.
  2. Design and Reliability:

    • Both movements are robust, reliable, and designed for durability, making them ideal for entry-level to mid-tier watches.
    • They use the same gear train and internal components.
  3. Functionality:

    • Day and date complications are adjusted by pulling the crown to the first position.
    • The hacking feature allows for precise time-setting.

Differences

Aspect 4R36 NH36
Branding Exclusively used in Seiko watches, often branded with "Seiko". Unbranded or marked with "SII", designed for third-party manufacturers.
Purpose Designed solely for Seiko’s in-house watches. Sold to external manufacturers and microbrands for use in a wide range of watches.
Calibration Pre-calibrated by Seiko for their watches, possibly with tighter tolerances. Usually not pre-calibrated; manufacturers are responsible for regulation.
Availability Not sold separately; only available in Seiko watches. Widely available through aftermarket suppliers.
Rotor Decoration Branded "Seiko" and sometimes decorated for higher-end models. Typically unbranded or marked with "SII". Custom rotors may be added by third-party brands.
Price Included in the cost of Seiko watches; not available standalone. Generally cheaper and available for purchase individually.

Use Cases

  • 4R36: Found in Seiko models like the Seiko 5 Sports and Seiko Prospex series. It is exclusive to Seiko watches and cannot be purchased separately for aftermarket use.
  • NH36: Popular among microbrands and aftermarket watchmakers due to its availability and affordability. It is widely used in custom or independent watch designs.

Which One Should You Choose?

  • Choose the 4R36 if:
    • You’re looking for a Seiko watch or need an authentic Seiko replacement for one of their models.
  • Choose the NH36 if:
    • You’re building or repairing a watch as part of an aftermarket project.
    • You’re working with microbrands or need a reliable movement for a custom design.

Conclusion

The 4R36 and NH36 movements are mechanically identical but serve different markets. The 4R36 is reserved for Seiko’s in-house watches and features their branding, while the NH36 is sold unbranded to external manufacturers, making it a versatile choice for independent watchmakers.