NH36 vs NH35A: Is the Upgrade Worth It?

Selecting the perfect movement for your mechanical watch project might seem daunting, especially when comparing similar options like the NH36 and NH35A from Seiko. Many watchmakers wonder if the slight price increase for the NH36 justifies the upgrade from the NH35A.

After extensively working with both movements across dozens of custom watch builds, I've gathered practical insights that can help you make an informed decision for your next timepiece.

Understanding the Basics of Seiko NH35A and NH36 Movements

Seiko's NH35A and NH36 movements belong to their renowned NH "Basic Mechanical Series" - though don't let the "basic" label fool you. Both movements deliver remarkable reliability and performance at accessible price points that have made them favorites among watchmakers worldwide.

Manufactured in Japan by Seiko Instruments Inc. (SII), these movements have earned stellar reputations among watch enthusiasts for their exceptional durability and consistent performance over years of daily wear.

Key Similarities Between NH35A and NH36

Looking at what these movements share helps understand why both remain popular choices:

Your watch will wind itself through natural wrist movements thanks to the automatic winding system built into both calibers
Manual winding capability gives you the freedom to wind the watch by hand whenever needed, ensuring power even during periods of inactivity
When setting the time, the hacking second hand feature stops the seconds hand completely, allowing for synchronization to the exact second
Each movement incorporates 24 jewels strategically placed to minimize friction between moving components, significantly extending lifespan and accuracy
Both operate at a precise frequency of 21,600 vibrations per hour (or 6 beats per second), creating that distinctive smooth sweeping motion watch enthusiasts love
When fully wound, the power reserve stretches to approximately 41 hours, keeping your watch running nearly two full days without wearing or winding
Physical dimensions remain identical at 27.4mm diameter and 5.32mm height, making them interchangeable in most watch cases without modification

The Defining Difference Between Seiko's NH35A and NH36 (Day-Date vs Date-Only Function)

The NH35A movement displays only the date, typically positioned at the 3 o'clock mark on the watch dial. Many watch designers prefer this cleaner look for minimalist or sport-focused timepieces.

The NH36 movement offers both day and date displays, showing you not just the current date but also the day of the week at a glance. This additional functionality transforms the watch into a more complete timekeeping instrument for everyday practical use.

Practical Considerations for Your Watch Build

When deciding between these movements for your custom watch project, several factors deserve consideration:

Dial Compatibility and Aesthetics

Your movement choice directly determines which dials will work with your build:

For an NH35A build, you'll need dials designed with a single date window that precisely aligns with the movement's date wheel position
For an NH36 build, your dial must accommodate both day and date windows, ensuring proper alignment with both wheels in the movement

Many watchmakers find the NH36's dual-window design adds a sophisticated, more premium look to their timepieces. The additional day display transforms the watch from a simple time-teller into a more comprehensive daily companion that provides complete date information without checking your phone.

Case Selection Considerations

While both movements share identical dimensions, their implementation differs slightly:

The identical 27.4mm diameter and 5.32mm height allow either movement to fit into the same watch cases
When building with the NH36, verify your chosen case provides adequate clearance for the additional day wheel mechanism and crown positions

Modification Potential and Creativity

Both movements offer excellent platforms for modification and personalization:

The NH35A works beautifully for cleaner, more minimalist builds where simplicity takes center stage
The NH36 provides greater creative possibilities with its additional functionality, allowing for more sophisticated dial designs and complications

Value and Investment Perspective

While the NH36 typically costs slightly more than the NH35A, the price difference remains minimal considering the added functionality:

The typical price difference ranges from $5-10, representing excellent value for the additional day function
The NH36 often commands slightly higher resale value in the secondary market for custom watches

Real-World Performance: Setting Expectations

In terms of accuracy and reliability, field testing shows virtually identical performance:

Both movements offer factory accuracy ratings of -20/+40 seconds per day, though real-world performance often exceeds these conservative specifications
Reliability remains consistent across both movements, with robust construction promoting long service life
With basic care, both movements will serve reliably for many years without requiring professional servicing

The decision ultimately hinges on whether the added day display function and more sophisticated aesthetic justifies the modest increase in cost - for most watchmakers, the NH36 represents the better value proposition.

Popular Applications and Practical Benefits

Watch enthusiasts commonly use these movements for several applications:

Many Seiko SKX owners upgrade from the original 7S26 movement to either the NH35A or NH36
The NH36 upgrade proves particularly valuable as it maintains the day-date functionality of the original SKX while adding hacking and hand-winding capabilities
Custom watch builders often choose the NH36 for its versatility across various watch styles, from dive watches to dress pieces

Looking to experience the NH36 movement firsthand? Our Seiko NH36 Movement Kit provides everything you need to assemble and understand this excellent caliber yourself!

Making Your Decision & Why the NH36 Often Wins

When deciding between the NH35A and NH36, consider these practical factors:

The NH36 provides both day and date information at a glance, eliminating the need to check your phone or calendar for the day of the week
The dual-display design of the NH36 adds visual interest and technical sophistication to your watch dial
The modest price difference makes the NH36 an excellent value proposition for the additional functionality
Both movements deliver identical performance metrics including accuracy, reliability, and power reserve

For a complete watchmaking experience featuring the superior NH36 movement, our Cabot Watchmaking Kit includes everything needed to build a professional-grade timepiece with this versatile caliber at its heart.

Conclusion

After comparing the NH35A and NH36 movements across multiple criteria, the NH36 emerges as the more compelling option for most watchmakers despite the slight price premium. The additional day-date functionality, more sophisticated appearance, and identical reliability metrics make it the preferred choice for custom watch projects.

Want to experience multiple movement types to compare? Our Mega Movement Kit Bundle includes the NH36 plus two other popular movements, allowing you to master various mechanical calibers while developing your watchmaking skills!

Regardless of which movement you select, both the NH35A and NH36 provide excellent foundations for custom watch projects, delivering reliable performance and the distinct satisfaction that comes from wearing a mechanical timepiece powered by a respected Seiko movement.

FAQ

Q. What makes the NH36 superior to the NH35A movement?

The NH36 offers both day and date displays compared to the NH35A's date-only function, while maintaining identical accuracy, power reserve, and reliability. This additional functionality justifies its slightly higher price and provides more complete time information at a glance.

Q. Will an NH36 movement fit in a case designed for NH35A?

Yes, both movements share identical dimensions (27.4mm diameter and 5.32mm height), making them perfectly interchangeable in most watch cases without any modification needed.

Q. Is the NH36 worth the additional cost compared to the NH35A?

Absolutely. The modest $5-10 price difference delivers the additional day display function, creating a more complete timekeeping experience and more sophisticated dial appearance that most watch enthusiasts consider well worth the investment.

Q. Which watch designs benefit most from the NH36 movement?

The NH36 excels in everyday wear watches where the day-date function proves most practical. It's particularly valued in dive watches, field watches, and professional-style timepieces where complete time information enhances functionality.

Q. How does the Cabot Watchmaking Kit showcase the NH36's advantages?

The Cabot Kit pairs the NH36 movement with premium components that highlight its day-date functionality through a carefully designed dial layout, creating a balanced, sophisticated timepiece that maximizes the movement's capabilities while remaining approachable for first-time watchmakers.