A rather rarely used ladies’ caliber is the Ronda 9138, which was later available under the brand name “Harley”.
The 9138 is on top of the Ronda movements in terms of features and quality. It has got a true swiss palett anchor escapement, an Incabloc-secured balance, beating with 21600 A/h and 25 jewels altogether. The rotor winds unidirectionally; on manual winding, the mechanism is not released, so that the last wheel spins very fast. Only the rotor is detached from the gear now.
The date mechanism advances slowly within the last 90 minutes of a day, but can be quickset on the second position of the crown.
This movement is not yet listed on the Flume K3 from 1972, but appears on the list of all Ronda movements from 1976, so that it’s release year can be estimated quite well. It might have been producted till the eigthies based on the fact, that the “Harley” name appeared just then and might be mostly well known because of the micro rotor caliber 2538.
|Number of jewels:||25|
Nickel anular balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Hairspring key|
|Winding mechanism:||yoke winding system|