MST 422

Description

In the mid 20th century MST (Roamer) launched many high quality movements. One of the is the 8 3/4 ligne caliber MST 422, a movement for ladies' watches with decentral seconds indication.

It bases on the caliber MST 367, but already uses a moveable hairspring stud.

Of course, all important bearings contain rubies. Without cap jewels, the movement only uses 15 jewels, even when the dial of the archived example interestingly adverties 17 jewels.

The rubies on the gear train bridge have a chaton-like edging.

The gear train uses the classical construction with mainspring barrel, center minute wheel, third wheel, decentral seconds wheel at position 6 o’clock and finally the escape wheel.

A monometallic screw balance is used, which slowly beats with 18000 A/h. Its precise frequency can be adjusted at the hairspring key only.

The modern execution of the movement can be seen on the moveable hairspring stud and the Incabloc shock protection for the balance wheel.

On the dial side, you see the yoke winding system, and at position 6 o’clock, there’s a large bearing jewel for the decentral seconds indication.

As common for the time, this movement is slanted on its outer rim, too, to save a little height.

Technical data

Usage gallery