PTS Resources Caliber F-8171

The PTS Resources caliber F-8171 is a regulateur style automatic movement with a pointer style 24 hour indicator and a disc style day/night indicator.

This movement has been produced since at least 2007. At that time, PTS Resources was categorizing this caliber as “Imitate Tourbillon” because of its open balance wheel (aka open heart or open escapement) feature.

24 Hour Indicator:

The 24 hour indicator works as a 12 hour hand , which is why in Stauer’s example, they use a double sided hand – a short side pointing at an inner row of numbers from 0:00 (12:00 AM) to 12:00 (12:00 PM), which is where the longer hand starts counting from 12:00 to 24:00 military time.

Other watches with this caliber may just have a regular hand with a 12 hour dial.

F-8171 VS F-8172:

Apparently there is also a calibre F-8172 (F8172). It is unconfirmed, but it is likely that the F-8171 has a silver tone balance bridge and the F-8172 has a gold balance bridge. If you know more about this, please comment below…

Similar Calibers:

There are a similar calibers F-8051 (F8051) and F-8052 (F8052), with the main difference being that instead of separated (regulator style) hours and minutes, the hours and minutes are both located between the center of the dial and 12:00 (or where the minutes hand is on the F-8171). The difference between F-8051 and F-8052 is likely the same as above – silver vs gold balance bridge.

Additional Resources:

• Official user manual from Stauer (pdf)