The B18 is a 21,600 bph, 3/4 plate hand winding movement, with hacking and hand-winding, from Beijing Watch Factory. It is originally based on the Miyota 8200 series, with the automatic winding deleted, and a good number of other changes. The original version used a mainspring barrel retention mechanism inherited from the auto-winding mechanism.
The initial version SB18 was replaced by an improved version B18-6 with the following main changes:
- The seconds (fourth) wheel moved from 4/5 o'clock to 6 0'clock position, allowing direct drive of the seconds hand, avoiding the "jumping seconds" effect.
- The winding mechanism is replaced by a classic he classic hand-winding barrel retention mechanism, improving the reliability and feel of the hand winding.
- Support for date function.
In addition to many minor changes, the B18-6 can be regarded as a design of its own.
Some specifications of the B18-6:
- Number of jewels: 18
- Diameter: 26mm
- Thickness: 4.01mm
- Power reserve: 42 hours
- Precision: -10～+25 seconds
- Number of parts: 158
- Features: Gold plated chatons; single swan neck fine regulator
The skeleton version is B18-6L.
- Official website: http://en.beijingwatch.com/item/50
- B18-6 Improvements: https://forums.watchuseek.com/f72/beijing-watches-evolution-sb-18-into-b18-6-important-changes-movement-4571775.html