The 10 1/2 ligne, unmarked and not having a caliber number, Würthner movement (in the literature, it is known as “Würthner 10 1/2”) is a simple constructed pin lever movement, which is made in a similar construction as compareable movements of Baumgartner or Brac. The only essential difference is, that the Würthner movement has got one additional transmission gear.
The plates are probably made of nickel silver and carry a pin lever movement in pillar construction according to Roskopf watches with an indirectly driven minute hand on the dial side and a large mainspring barrel.
The small ring balance is not shock protected and runs in two steel bearings. The only one jewel used is in the ellipse of the balance.
On the dial side, as a little surprise, you find a yoke winding system, which is again a very simple, but efficient construction.
This movement, which is made in the late 1950ies, is pretty rare, probably because of too many similar and cheap(er) pin lever movements of other german and swiss manufacturers.
The movement was reworked over the time, the younger version was also noted as “OC Cal. R 1”, but differs at least in size from the other movement, which I know as OC Cal. R 1. Nevertheless, it seems, like they are from the same family.
|Number of jewels:||0/1|
Nickel anular balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Long regulator arm / hairspring key|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||1 hole(s)|
|Functions:||hour, minute, decentral second|
Flume: 1957 39|