When Smiths entered the civilian watch market in 1947 they introduced their calibre 12.15 This was a sub seconds 15 jewel movement. The jeweller J.W. Benson had a special 12.16 version that featured 1 additional jewel. The final version (27.SC) with centre seconds was used in British army issued W10 watches up unto the early 1970’s. That version was fully shock protected, featured hacking lever and had 17 Jewels.
Smiths Calibre: 12.15-27.SC
- Made approximately: 1947-1970
- Made in United Kingdom
- Power reserve 41h
- 15-17 Jewels
- 18000 B/A
- Lift angle 52°
- DM 26.6mm
- H 4.4mm-5.55mm(ZS)
Surface finish on the 12.25 consists of gilt plating with no surface decoration. All the screws are polished. The bridges have chamfered edges. Ratchet and crown wheels are well made, but lack any fine finish.
Surface finish on top side of the plate and bridges: 6
Surface finish on screws: 7 Points
Surface finish on crown and ratchet wheel: 5 Points
Movement Jeweling: 6-7* points
The movement was a standard design for 1947
Movement design innovation (for 1947): 6 points
The Smiths base plate has no decoration, but has a decent finish. Winding mechanism is very solid. Gear train has a nice finish on wheels and pivots.
Base plate finish: 6 Points
Setting and winding mechanism: 7 Points
Gear-train finish: 8 Points
Movement durability: 7 Points
First model did not have shock protection. Later versions had shock protection and the final version also had an adjustable stud carrier.
2-4* Bonus points
Hacking lever.
2* Bonus points
The Smith calibre 12.15 in good condition are usually good timekeepers. Accuracy: 8 points
Power reserve is fair: 7 points
Smiths calibre: 12.15-27SC summary:
Surface finish on bridges and top side of base plate: 6
Surface finish screws: 7
Surface finish on ratchet and ratchet wheel: 5
Movement Jeweling: 6*7
Movement innovative design for ca 1947: 6
Base plate finish: 6
Setting and winding mechanism: 7
Gear-train finish: 8
Movement durability: 7
Total bonus points: 2-6*
Accuracy: 8
Power reserve: 7
Grand total: 73-80*
*Bonus points.
Weakness: barrel arbour surface in barrel bridge gets worn. A sign of this is when you see wear marks of the ratchet wheel in the barrel bridge surface. Re bushing of barrel bridge solves the problem.