Union Glashutte Caliber UNG-56.S1

The Union Glashütte caliber UNG-56-S1 is a handwound mechanical watch movement with a small seconds subdial and a power reserve indicator.

Text on the movement:

60 STUNDEN GANGRESERVE (60 hours power reserve) / SILIZIUM (silicon) with Si emblem /  ZWANZIG (20) RUBINE (20 jewels) / MADE IN GERMANY

Silicon Balance Spring:

The UNG-56.S1 is equipped with a silicon hairspring (aka balance spring) for magnetic resistance. Here is how the brand describes the use of this material in their watches:

“UNION GLASHÜTTE uses Silicon, a chemical element of the family of metalloids, in the manufacture of balance springs. By use of Silicon, our watches are insensitive to magnetic fields, temperature fluctuations and shocks. They are very stable in shape and resistant to oxidation. The silicon spiral guarantees higher power stability in our mechanical movements – so your watch runs precisely anytime, anywhere. You can recognize the use of the silicon spiral in your UNION GLASHÜTTE watch by the Si-poster that our watchmakers set and align by hand.” –Source

VIA ETA?

You may see this movement described as being produced in partnership with ETA, however, it’s important to acknowledge that both Union Glashutte and ETA are owned by the SWATCH Group conglomerate of watch brands. The details are unclear, such as: were the parts made in Switzerland at ETA, then assembled in Germany at Union Glashutte? What we do know is what can be seen from the stock photos of the movement, that the anti-shock device is a Nivachron, exclusively found on watches produced by the Swatch Group.

Quick FAQs:

Can you overwind the mainspring?
No. Union Glashutte states that you cannot overwind the UNG-56.S1 – or, as they say: “It is not possible to overtension the mainspring.”

When shouldn’t you change the date?
According to the official instruction manual, never set the date between the hours of 8:00 PM and 2:00 AM, as this is the period of time when the date changing mechanism is engaged – doing so could damage the movement.

What are the recommended service intervals?
While Union Glashutte does not specify a recommended time-frame for servicing your UNG-56.S1 powered timepieces, they do recommend having an AD inspect your watch every 3-4 years. From there, they more likely to get you to agree to a servicing while face-to-face with a sales professional, rather than through written text deep in an instruction manual (this isn’t to say you shouldn’t get your watch serviced in that case, but more of a commentary on the different approach being used to engage the customer on this topic).

Additional Resources:

• Official instruction manual (pdf)