10 1/2”’ | Hand Wind | Swiss Lever | Direct Sweeping Seconds |

Remarks:

• Rocking bar winding
• Click on the dial side
• Movement exists in different variants:
  • Setting lever pin or screw
  • Massive bridges or pillar construction
• Movement family:
  • Osco 65: no date
  • Osco 66: no date, differences to 65 not known
  • Osco 66D: date

• Listing ID: 13699
• Manufacturer / Brand: Osco
• Caliber: 66
• Size in French Lignes: 10 1/2'''
• Size range mm largest diameter: 22 - 31 mm
• Shape: Round
• Winding: Manual (Crown)
• Hands Setting: Crown
• Seconds Hand: Sweeping seconds (central seconds)
• Escapement: Lever (Swiss, English, Glashütte)
• Date, Day, Month...: None
• Jewels: 19
• Setting Lever Screw/Pin Position: Left
• Balance Position: Bottom (120 - 240°)
• Shock Protection: Protax
• Beats per hour: 18,000
• Balance Type: Nickel
• Power Reserve: Approx. 40 hours
• Production Period: Unknown, Probably around 1957
• Country: Germany
• Identification: Marked with OS 66 under the balance. Listed in the Flume K1 catalog in the part from 1957.
• Contributor ©: Uhrforum.de member buchenhain
• External Link: https://uhrforum.de/threads/identifizierte-uhrwerke-die-weder-bei-ranfft-lorenz-noch-im-watch-wiki-zu-finden-sind.86322/page-72#post-10100631