NH35 or NH36? Choosing Your Seiko Movement Kit

Building a custom watch is an exciting journey that combines craftsmanship with personal style. One of the most critical decisions in this process is choosing the watch movement NH35 or NH36, the engine that powers your timepiece. Seiko's NH35 and NH36 movements are two popular choices among watch enthusiasts.

Both offer reliability and solid performance at an accessible price point. Understanding the Seiko NH35 vs NH36 comparison will help you select the ideal movement for your next project.

Understanding Seiko Movement Kits

Seiko has earned a stellar reputation in the watchmaking world for producing high-quality and dependable movements. The NH35 and NH36 are part of their respective NH series, known for robust construction and accurate timekeeping. These automatic movements are favorites among both professional watchmakers and hobbyists due to their balance of quality and affordability.

The NH35 is the unbranded equivalent of Seiko's own 4R35 caliber, and the NH36 corresponds to the 4R36. Seiko's subsidiary TMI (Time Module Inc.) manufactures the NH versions for third-party brands and independent builders. Seiko Instruments (SII) produces the branded 4R variants for Seiko-branded watches. The internal mechanics are identical, so NH movements deliver the same proven engineering at a lower cost. 

Comparing the NH35 and NH36 Watch Movements

While the NH35 and NH36 share many similarities, key differences between them might influence your choice.

Common Features

Both movements come with:

• Automatic and Manual Winding: They can self-wind through wrist motion and also be manually wound via the crown.
• Hacking Second Hand: Allows stopping the second hand when setting the time, enabling precise adjustments.
• 24 Jewels: Use of jewels reduces friction within the movement, enhancing accuracy and longevity.
• Frequency of 21,600 VPH: Operating at 21,600 vibrations per hour ensures a smooth sweep of the seconds hand.
• Power Reserve: Approximately 41 hours of power when fully wound.

Key Differences: Day & Date Complication

The most significant difference between NH35 and NH36 comes down to one complication: the day display. 

Day and Date Complication

The NH35 features a date-only display, typically at the 3 o'clock position. The NH36 offers both day and date displays, adding a second complication to your watch. Choosing the NH35 means a simpler dial layout with fewer windows. Opting for the NH36 provides the convenience of viewing both the day and date at a glance.

Worth noting: the NH36's dual complications (date and day-date) make it the more complex movement to work with. Most watchmaking educators recommend starting with simpler movements before tackling the NH36.

The NH36's day wheel typically defaults to English, but the wheel itself is interchangeable. Alternative day wheels in Japanese, Arabic, and other languages are available separately, giving builders an extra layer of customization.

One critical maintenance detail for the NH36: never adjust the day or date when the watch reads between 9 p.m. and 3 a.m. During those hours, the calendar gears are actively engaged. Forcing a change in that window can damage the day-date mechanism. Set the time to 6:30 before making any calendar adjustments to stay safely outside the danger zone.

Design and Dial Considerations

Your movement choice directly impacts the dial and overall design of your watch.

• For NH35: Select a dial with a single date window aligned correctly with the movement's date wheel.

• For NH36: Choose a dial that accommodates both day and date windows, ensuring they align perfectly with the movement.

Consider your aesthetic preferences. If a minimalist design appeals to you, the NH35's simpler dial might be ideal. If you appreciate additional complications and a more detailed dial, the NH36 offers that sophistication.

One practical factor to weigh: most aftermarket dials are cut for the NH35's date-only aperture. The NH35 offers a noticeably wider selection of compatible dials compared to the NH36, which requires a day-date cutout that fewer manufacturers produce. Builders who want maximum dial variety may find the NH35 a more flexible starting point.

Case Compatibility

Both movements share similar dimensions:

• Diameter: Approximately 27.4 mm
• Height: Around 5.32 mm

This similarity means they can fit into the same watch cases. However, if opting for the NH36, double-check that the case provides enough space for the additional day wheel.

Performance and Reliability

Renowned for their reliability, both the NH35 and NH36 power numerous watches, including models in Seiko's own Seiko 5 series. Their robust construction and ease of maintenance make them excellent choices for custom watch projects.

Seiko NH35A Movement: Full Specifications and Performance Review

The Seiko NH35A is a 24-jewel automatic mechanical movement produced by Seiko Instruments (SII/TMI) - the unbranded equivalent of Seiko's own caliber 4R35. Its core specs: 27.4mm diameter, 5.32mm height, 21,600 vph beat rate, 41-hour power reserve, and an accuracy rating of -20 to +40 seconds per day. It supports both automatic winding via a bi-directional Magic Lever rotor and manual crown winding, plus hacking seconds - the seconds hand stops when the crown is pulled out, enabling precise time-setting.

For a watch movement kit, these specs translate directly to build decisions. The 5.32mm height sets a minimum case depth requirement; the date wheel position (3 o'clock on the NH35A) dictates your dial cutout placement; and the 27.4mm diameter must clear your case movement seat. The NH35A ships in two rotor variants - Japan-marked and Malaysia-marked, with TMI-marked rotors now the most common - though internal performance is identical across variants.

In practical performance terms, the NH35A consistently delivers within its rated tolerance when fully wound and worn daily. Its Diashock protection provides adequate shock resistance for everyday wear including active use. The main tradeoff versus higher-beat movements like the Miyota 9015 is sweep smoothness (21,600 vph produces a slightly choppier seconds hand motion), but for a movement kit at this price point, reliability and part availability are the stronger considerations.

Which Movement Should You Choose?

Your decision between the NH35 and NH36 depends on personal preferences and the features you value in a watch.

Choose the NH35 if you:

• Prefer a minimalist aesthetic with a clean, uncluttered dial.
• Want a slightly simpler assembly process for your watch build.
• Value essential features without additional complications.

Choose the NH36 if you:

• Desire the added functionality of a day display alongside the date.
• Enjoy a more complex dial design with extra features.
• Aim to create a watch that stands out with its detailed complications.

The NH36's additional features offer increased convenience and sophistication, making it a popular choice among watch enthusiasts.

As a standalone movement, the NH35 typically costs $10 to $15 less than the NH36. The savings are modest on a single build, but they add up for builders planning multiple projects or experimenting with different configurations.

Ready to start your project with the NH36? Check out the Seiko NH36 Movement Kit at Rotate Watches.

 

 

Integrating the Movement into Your Watch Build

When building your watch, ensuring all components are compatible with your chosen movement is essential.

Dial Selection

• NH35: Choose a dial with a date window positioned correctly to align with the movement.
• NH36: Select a dial that accommodates both day and date windows, ensuring proper alignment.

Proper alignment is crucial for both the functionality and appearance of your watch.

Hands Compatibility

Select hands that fit the movement's pinion sizes:

• Hour Hand Opening: 1.5 mm
• Minute Hand Opening: 1.0 mm
• Second Hand Opening: 0.2 mm

Using the correct hand sizes ensures seamless operation and optimal performance.

Case Selection

Verify that your watch case suits the movement's dimensions and complications. While the NH35 and NH36 share similar sizes, confirm that the case accommodates the NH36's additional day wheel if necessary.

Find compatible components at Rotate Watches for quality parts and accessories.

Other NH Series Movements Worth Knowing

Not every build needs a date or day-date display. Seiko's NH family includes the NH38 and NH39 for builders who want a clean, no-date dial without any calendar window. The NH70 and NH71 serve a similar role but feature a skeletonized design, making the movement visible through the dial. All of these share the same case footprint as the NH35 and NH36, so they accept the same cases and hands. Builders planning a dress watch or minimalist field watch should consider these alternatives alongside the NH35 and NH36.

Examples of Watches Using NH35 and NH36 Movements

Understanding where these movements are used can help inform your decision.

• NH35: Frequently found in microbrand watches and custom builds due to its reliability and simplicity. Brands appreciate its classic design and ease of use.
• NH36: Powers many of Seiko's own watches, such as the Seiko 5 Sports series, admired for its day-date functionality. It's favored among enthusiasts who value added features without sacrificing reliability.

Their widespread use ensures that spare parts and aftermarket components are readily available, benefiting custom watch builders.

Essential Tools for Your Watch Build

Assembling a watch requires precision and the right tools. Before you begin, make sure to:

• Gather required tools like watchmaker's screwdrivers, tweezers, and a watch case press from your Rotate Watch Making kit.
• Wear gloves to prevent oils and dirt from transferring to the movement or dial.
• Use a dust blower and Rodico putty to keep components clean during assembly.

Having the proper tools ensures a smoother assembly process and a professional result.

Consider movement kits from Rotate Watches, which may include essential tools to simplify your build.

Conclusion

Choosing between the NH35 and NH36 movement kits is a significant step in your watch-building journey. Both offer reliability and precision, but the NH36 provides additional functionality with its day-date display, offering convenience and a more sophisticated aesthetic. Its versatility and widespread use make it an excellent choice for both novice and experienced watchmakers.

Building your own watch is more than assembling parts; it's about creating a timepiece that reflects your style and personality. With the NH36 movement kit and some dedication, you can craft a watch that's truly unique.

Ready to create your custom timepiece? Start with the Seiko NH36 Movement Kit from Rotate Watches.

FAQs

Q. Is the NH36 movement reliable?

Yes, the NH36 is highly reliable and widely used in the watch industry for its durability and accuracy.

Q. Does the NH36 support hacking and manual winding?

Absolutely, the NH36 features hacking seconds and allows for manual winding.

Q. Is Seiko NH35 a good movement?

Short Answer: Yes, the Seiko NH35 is widely regarded as a reliable, durable, and affordable automatic movement.

The NH35 movement is a popular choice among watch enthusiasts and watchmakers due to its robust construction and precise timekeeping. It is highly reliable, offers features like hacking seconds and manual winding, and is commonly used in both custom builds and microbrand watches.

Its affordability makes it accessible for both hobbyists and professionals looking to build a quality timepiece without breaking the bank.

Q. What is the price of Seiko NH35A movement?

Short Answer: The Seiko NH35A movement generally costs between $20 and $50, depending on the seller.

The Seiko NH35A is a highly affordable movement often used in budget-friendly automatic watches. Prices can vary based on the retailer and whether it is purchased as part of a movement kit.

It offers great value considering its reliability and ease of use, making it a favorite for watch enthusiasts who want a cost-effective option for custom watch builds.

Q. Can I use any dial with the NH36 movement?

You'll need a dial designed specifically for both day and date windows to align properly with the NH36.

Q. Where can I find compatible components for the NH36 movement?

Compatible dials, hands, and cases are available at Rotate Watches.

Q. What tools are essential for assembling my watch with the NH36 movement?

Gather required tools like watchmaker's screwdrivers, tweezers, gloves, and a watch case press to ensure a smooth assembly process.

Q. Is the NH35 the same as the Seiko 4R35?

Yes, the NH35 is the unbranded version of Seiko's 4R35 caliber. TMI (Time Module Inc.), a Seiko subsidiary, manufactures the NH35 for third-party brands and modders. SII (Seiko Instruments) produces the 4R35 for Seiko-branded watches. The internal mechanics, accuracy rating, and power reserve are identical across both versions.

Q. Does the NH36 have a date setting danger zone?

Yes. Never adjust the day or date when the NH36 reads between 9 p.m. and 3 a.m. The calendar gears are engaged during those hours, and forcing a change can damage the mechanism. Set the time to 6:30 before making any day or date adjustments to stay safely outside the danger zone.

Q. Can I change the day wheel language on the NH36?

Yes. The NH36 day wheel typically ships in English, but the wheel is removable and interchangeable. Replacement day wheels in Japanese, Arabic, Spanish, and other languages are available from aftermarket suppliers. Swapping the wheel requires basic movement disassembly skills and a steady hand.

Begin your watch-building adventure today with the Seiko NH36 Movement Kit and quality components from Rotate Watches.