Seiko Tmi Caliber Vh60 Vh60a Vh60b

Seiko Instruments (SII/TMI) Caliber VH60

Seiko Tmi Caliber Vh60 Vh60a Vh60b

ManufacturerSeiko Instruments Inc. / SII / Hattori / TMI
Caliber NumberVH60, VH60A, VH60B
TypeQuartz
Lignes
10.5”’
Diameter
23.70mm
Casing Diameter
23.3mm
Height3.45mm thick
Jewels
2
Frequency32,768 Hz
Accuracy Rating
See below…
Battery Cell Number371 (SR920SW)
Battery Life
~2 years
Quartz TypeTuning fork type quartz crystal
Driving System
Step motor
Stem351177 (tap 10)
Hand Sizes1.20mm / .70mm / .17mm / .20mm
FunctionsCentral hours; central minutes; central seconds; 24 hour subdial at 6:00
Other Features
True no-date
Hacking Seconds?
Yes
Country of ManufactureJapan
Known Models (Too many to list. Add your watch in the comments below…)

The Seiko Instruments (SII) caliber VH60 (VH60A, VH60B) is sweep-seconds quartz movement with a 24 hour indicator at 6:00.

This caliber is part of the VH (or VH6) family of quartz movements that Seiko refers to as their Sweep Second Quartz Series.

Because of the sweeping seconds hand that looks similar to functionality of a mechanical watch, the watch community often bundles this movement into the mechaquartz style of movements.

VH60 VS VH31:

The VH31 is a 3-hander no-date, and is used as the base for the VH series. The VH60 being discussed here adds a 24 hour subdial at 6:00.

24 Hour Subdial:

The 24 hour subdial at 6:00 is essentially a pointer style day/night indicator. It can also be used to decipher military time. The 24 hour time is not an independent time or GMT. It cannot be independently set.

To set the 24 hour time, it follows the path of the main hour hand above, but in 24 hour time (sometimes referred to as military time).

  1. Simply pull the crown out one click to time setting mode and advance the hands to the correct time.
  2. Rotate the hands around the dial one or two laps depending on if the current time is AM or PM.
  3. Press the crown back in.

When was the VH60 introduced?

The VH series was introduced in 2015, although updated official technical documentation for the VH60B was found dated September 2, 2022.

Sweeping Seconds:

As a mecaquartz type of movement, the second hand on the VH60 has a rather smooth sweeping motion, unlike most quartz watches that impulse with a ticking motion. The seconds on a VH60 sweep at 4 beats per second (2Hz) which is slower than a typical automatic (for example the NH35A beats 6 times per second), but much smoother than a regular 1 beat per second quartz.

How TMI describes it:

“Centre second hand moves 4 times per second, resembles mechanical movements.”

Torque:

According to TMI, the torque of a standard quartz movement’s central seconds hand is about 0.07uN-m, whereas the torque of a VH series is approximately 0.30uN-m (about a 400% increase in torque). These stats are based on comparisons with their own “common” quartz calibers (the caliber PC21J for example).

Accuracy Rating:

Seiko/Time Module Inc. states that the expected accuracy of this calibre is +/- 15 seconds per month at normal operating temperatures of -5C to + 50C (23F – 122F). There is no way to regulate or adjust this movement.

Battery Replacement:

The VH60 battery life is about 2 years. The cell number for replacement is 371 (SR920SW).


To change the battery, use your tool to gently hold the retaining tab to the side, allowing the battery to pop up.

Sii Caliber Vh31 Battery Replacement

Stem Removal:

The official instructions aren’t the easiest to follow, but you can find them below for reference. There is a small triangle shaped lever with an circular indentation. You will gently press that while extracting the stem. As for which position the crown should be in for removal, Seiko makes that part easy: the lever is most visible in the position that is ideal for stem extraction, the lever hides when in the incorrect position.

In other words, it is only in clear view when the crown is in the correct position, so there is no need to worry about which position to put the crown in when pressing the detent button/tab. Using your tweezers or a toothpick, gently push down the tab/lever while pulling out the stem.

Seiko Vh31a Stem Extraction Instructions

VH60 Replacement Prices:

At the time of this post, replacement prices for this movement were not found online. Access to this movement may be limited to wholesale account orders or parts watches.

TMI/SII/Hattori:

You might find this caliber VH60 listed as being produced by SII aka TMI (Time Module Inc) aka Seiko Instruments Inc. Some are signed SII and others are signed TMI. Learn more about the different names here.

Video of the seconds hand:

Here is a short dial side video to show the smooth sweeping seconds on the VH31. This should give you an idea of how smoothly the VH60 would sweep. At a quick glance you’d think it was an auto with a stuttering seconds hand!

VH60 Tech Sheets (pdf):

Additional Resources:

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