Think about all of the mods you personally built - if you’re new to Seiko mods, think about all the mods you’ve seen on social media. How many of those do you think are powered by a quartz movement? The answer would be, too few to notice, if there was any at all. The vast majority of Seiko mods utilize traditional automatic or mechanical calibers as the base. Quartz powered watches get often overlooked, despite their unique viability and favorable attributes for ambitious modding projects.

Quartz movements, with their timed vibrations powered by battery and integrated circuit, revolutionized watchmaking in the 1970s and 80s (and how it almost brought down the Swiss watchmaking industry). The technology enabled precise timekeeping and accessibility for the masses. However in recent years, enthusiasm has returned to manual and automatic movements driven by mainsprings and winding rotors. Still, quartz offers some clear opportunities for the practical yet adventurous Seiko modder.

What are Quartz Movements?

Source: The Seiko Guy


Quartz refers to the crystallized silicon material that vibrates at a precise frequency when introduced to an electrical charge. By integrating a tiny quartz crystal into an analog watch, the vibrations can drive the motor and gears to move the hands. This results in impressive accuracy of within 15 seconds per month, a far cry compared to potentially 15 seconds per day with even high-end mechanical movements.

Quartz powered watches offer some clear advantages for a daily watch:

Accuracy - The precision of quartz means the watches are extremely accurate, to within mere seconds per month. This is perfect for those wanting reliability in timekeeping without constant adjustment that mechanical watches require.

Affordability - Not needing to manufacture complex mechanisms with hundreds of moving parts means quartz watches can be produced at much lower costs. Seiko quartz movements are accessible and cheap to purchase.

Reliability - With simpler construction and fewer components, quartz movements tend to have a longer lifespan without expensive servicing needed down the road. They are also less impacted by shocks and vibration.

However, quartz does come with some drawbacks that enthusiasts are not so keen about:


Source: Uhrmacherwerkzeuge

Perceived ‘lack of soul’ - The opinion that worrying only about accuracy and not the craftsmanship of watchmaking makes quartz movements boring. There's satisfaction in automatic and mechanical processes that mimic human heartbeat or interaction. Just think of the debate around electric and gas cars and you’ll know what we mean.

Environmental impact - Batteries have to be replaced, posing greater long-term waste as well as opening up the watch during battery replacement if water resistance is expected. Some eco-conscious watch fans see this as negative, unlike with purely mechanical movements that are easier to recycle or upcycle.

Less tinkering - Quartz just works, taking away some ability to disassemble movements and service/oil components over years of ownership. The simplicity leaves little for hobbyists to adjust and experiment with. This can be a plus for non-experienced modders who may be too intimidated to fiddle with the movement, but a point of contention for the more curious modder.

Unique Attributes for Modding

Source: Adventures in Amateur Watch Fettling


Beyond abundant supply, quartz offers other advantages for Seiko modders that automatic and mechanical movements can’t match.

One major incentive is quartz enables additional complications like chronographs, alarms, and calendars that are either impossible, extremely rare, or costly to find in automatics. Why hunt down a rare 6138 movement when a 7T32 chrono is easily available?

Accuracy and lower maintenance needs also provide faster and lower risk experimentation with wild mods. Fears of ruining an intricate mechanical movement or needing constant corrections are gone with quartz. Mods can also focus purely on cosmetic changes without adjusting pins, gears, and servicing internals.

And the free space underneath from eliminating a winding rotor or mainspring provides new frontiers previously unavailable to automatic Seikos. High domed crystals, exhibition casebacks with engravings, and thicker inner bezels become options.

Quartz Movements for Seiko Mods

Source: Mizeni


While Swiss and Japanese watch companies were battling quartz versus mechanical movements in the mainstream watch market, Seiko was a leader in both. This has left an abundance of affordable quartz calibers that can be viable for watch modding. One movement in particular that seems usable for mods is the Seiko 7N43, sharing a lot of characteristics with the NH35 with a few upgrades. 

The 7N43 is a versatile and common quartz movement used by Seiko across many of its watch lines, but most famously in the aviation-themed Flightmaster watch. This battery-powered caliber features the standard three hands to display hours, minutes, and seconds. It also has windows at the 3 o’clock position to display both the current day and date.



In watchmaking terms, the 7N43 is referred to as an 11 1/2 ligne movement. This simply refers to its size - with case dimensions measuring roughly 21.9mm x 23.5mm and just at 2.9mm thin. That’s almost half the size of your standard NH35, and a full millimeter thinner than the Miyota 9015 - a feat that you just can’t so easily do unless you have a quartz caliber.

This movement is available for as low as $15, doesn’t that sound like an interesting experimental project? However, since the Seiko modding community is evidently more enamored with mechanical offerings, there are no compatible parts for the Seiko 7N43 yet, at least none that we know of. Modding with this calibre may require extra steps at this time, such as 3D printing a few holders and spacers for it to be compatible with available cases.

Wrap Up

While quartz watch movements may not garner the same attention as complicated mechanical engines among purists, they offer creative opportunities not found in automatics. The complexity of chronographs, calendars, alarms, and other complications widen possibilities for customization. Not needing to service finicky internals also simplifies experimentation. And additional space under the dial expands the canvas for the modder’s imagination.

The hallmark of any modding culture is invention, not tradition. Quartz movements, with accuracy that now runs circles around even high-end Swiss watches, enable reliable base calibers for one-of-a-kind designs. Any assumptions that battery-powered means soulless or boring simply do not account for the unique potential enabled by the unique characteristics of a mechanical caliber. 

That said, if you’re yet to fully explore the potentials of the beloved Seiko NH platform, you’re in the right place! namokiMODS offers literally over 1000 cross-compatible parts for infinite possible part combinations, so you can create a personalized 1 of 1 watch. From Titanium diving cases to Olive green field watches, down to the caseback and crystal gaskets, we have everything that you will need for a complete watch. Be sure to check out our store for your premium watch build.

Happy modding!

February 03, 2024 — Jeremiah A


Jay said:

I would like to use some quartz movements in NH35 cases but the spacers are the challenging part.

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