CK2915-2
Speedmaster Pre-Professional Broad Arrow CK2915 — CK2915-2
Second series, essentially identical to the -1: Base 1000 metal bezel, broad arrow hands, “fat” oval O and bevel-engraved caseback. Archive-dated examples 1958–January 1959, movement numbers 15.50M and 15.99M.
One Phillips essay estimates 3,000–4,000 made. Observed movement numbers cluster around 15.49M, 15.5M, 15.99M and 16.64M.
Identifying details
- Broad arrow hands
Wide arrow-shaped hour and minute hands of the first Speedmaster.
- Steel tachymetre bezel
Metal bezel with engraved or etched scale and no insert.
Variants of CK2915
Reference overview →| Variant | Production |
|---|---|
| CK2915-1 | 1957–1958 |
| CK2915-2Current | 1958–1959 |
| CK2915-3 | 1959 |
| CK2915-3 · CK2915-3, Broad Arrow Hands | Undated |
Case & movement
- Reference
- CK2915
- Production
- 1958–1959
- Case material
- Stainless steel
- Case diameter
- 38.5 mm
- Crown
- 7 mm
- Crown guards
- None
- Movement
- Manual winding
- Caliber
- Omega 321
Dial, bezel & hands
Movement
Omega 321
Hand-wound column-wheel chronograph of Lemania origin (Lemania 27 CHRO C12 / 2310 family), used by Omega from 1946 to 1968 and in every Speedmaster up to the 145.012. Early examples have a symmetrical clutch bridge; later ones an asymmetrical bridge.
Manual winding · Introduced 1946 · 18,000 vph · 17 jewels · Ø 27 mm