MST 264,  296 
Ligne12''' 12'''
Cal. 264 (c) David/Mirius Cal. 264 early barrel bridge (c) David/Mirius Cal. 264 later barrel bridge and shock resist

Remarks: This appears to be the first calibre for which Roamer experimented with shock-resist. This movement (and others) were also later available with incaloc. The three finger bridge on the MST 264 movement is real, unlike the later 352 and 364 calibres. Being the only 12''' Roamer calibres, the 264 and 296 share few parts with others, clickspring and click aside. The 296 is a later version of the calibre with only a single train bridge which is much cheaper to manufacture compared to the separate fingers, each of which needs a screw and a location pin. The movement itself is very well finished and reinforces MSTs dedication continual improvement. It seems likely this movement would have replaced the 13''' MST 175. It also seems likely that this movement would have been replaced by the 11.5''' MST 364. The date range given below is based on this reasoning.
 
Production period: 1927 - 1938

Jewels: 15
Beat: 18000
Winding: manual
Manufacturer: MST
Hand sizes:
Hour:150
Minute: 80
Second: 19
  
Stem tap size: 120

Variant:
MST 264 12''' (26.70mm) sub second, three finger train bridge
MST 296 12''' (26.70mm) sub second, single train bridge

Common parts/Interchange
Multiple balance staffs possible:
MST part number:7447,  interchanges with MST: 264, 296
MST part number:7448 (inca),  interchanges with MST: 264, 296
MST part number:7449 (SR),  interchanges with MST: 264, 296
Mainspring:
MST part number:1235 interchanges with MST: 264, 296
Strength: 1.200
Height: 1.75
Length: 300
Watches in my collection with the MST264:

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