Osco 300

 
Osco 300

Osco 300

Description

The 10 12 ligne Osco 300 is part of the large movement series, which Osco launched in the 1060ies.

The caliber 300 uses an indirectly driven center second, which is beared under an own and well executed cock.

base plate

base plate

Unlike the simpler models of the caliber family, all important bearings contain rubies. Nevertheless, the construction principle - a pillar construction with a rocking bar winding system - is used here, too.

gear train

gear train

Due to the pillar construction, the gear train builds pretty high. It consists of the mainspring barrel, which drives the center minute wheel, followed by third wheel, seconds wheel and steel escape wheel, whose bearing has got even a cap jewel on the movement side.

The axle of the third wheel is prolonged, on its end on top of the upper gear train bridge, there’s the transmission wheel, which drives the center second. Its gear is beared under an own cock, which is secured by two screws - pretty costly.

A friction spring adds a little tension and avoids fluttering of the second hand.

side view of the gear train

side view of the gear train

The slim anular balance beats slowly with 18000 A/h. She is beared in two KIF Trior shock protections. The effective length of its hairspring can only be adjusted with the hairspring key only. This was usual in the price range of these watches.

Osco 300: Dial side

Osco 300: Dial side

Since the Osco 300 uses a rocking bar winding system, the ratchet is located on the dial side and here it has got a very well executed true pawl.

In general, the dial side makes a pleasantly tidy and clean impression, which is not necessarily a matter of course for a pillar factory.

Technical data

Manufacturer:Osco
Caliber:300
Number of jewels:17
Escapement:Pallet lever
Balance types: Nickel anular balance
Shock protection(s): KIF Trior
Balance bearing / direction hairspring:Clockwise
Moveable stud:no/yes
Adjust mechanism:Hairspring key
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel, center minute wheel, mainspring barrel
Construction type:pillar construction
Winding mechanism:rocking bar winding system
Setting lever spring:1 hole(s)
Features:SCI
Functions:hour, minute, second
A/h:18000
Size:10 1/2''' (measured: 23,3mm)
Literature: Flume: K3 34
Inventory number:19024

Usage gallery

Häfele Hanomag gents watch (case broken)

Häfele Hanomag gents watch (case broken)

This movement and watch was donated by Lars Schröder. Thank you very much for your support of the movement archive!