MST 417 
Ligne12'''

Remarks: A completely original alarm calibre, features 2 barrels - main and alarm, both wound from the same crown. Similar in design to the Vulcain Cricket in that it uses a crown wheel rocker to switch between barrels depending on direction crown is wound. Roamer took out patents relating to the design of the special sounding back. This is the first version of the Alarm calibre, and is rarer than the modified MST 427 that replaced it.
 
Production period: 1952-1955

Jewels: 17
Beat: 18000
Winding: manual
Manufacturer: MST
Hand sizes:
Hour:150
Minute: 90
Second: 19
4th hand: 220
  
Stem tap size: N/A

Variant:
MST 417 12''' (27mm) Alarm

Common parts/Interchange
Balance Staff:
MST part number:7480,  interchanges with MST: 427
Multiple mainsprings possible:
MST part number:1270 (Main) interchanges with MST: 427
Strength: 0.1100
Height: 130
Length: 345
MST part number:1271 (Alarm) interchanges with MST: Nil
Strength: 0.825
Height: 200
Length: 320
Associated Patents:
CH295436Alarm hammer mechanism
Deposited 1951, granted 1953
Watches in my collection with the MST417:

All text and images are either © Kris Bubendorfer 2011-15 or © Roamer Watch Company.