Component record · Case
Case Back
VerifiedThe rear cover of the watch case, closing off the movement from behind.
What it does
Seals and protects the movement from the rear, and is commonly the location for hallmarks, engravings, presentation inscriptions and (on water-resistant watches) a gasket seal.
How it works
Case backs may be hinged (opening on a pivot, common in earlier pocket watches), screw-fitted (threading directly onto the case body, common on both antique and modern watches), or snap-fitted (pressed on and retained by friction, common on many mass-produced modern watches).
On water-resistant watches, a gasket seated in a groove between the case back and case body compresses when the back is screwed or pressed home, excluding moisture to the watch's rated depth.
Interior surfaces of case backs frequently carry hallmarks, serial numbers, import marks, and sometimes owner's presentation engravings, all of which are valuable to dating and provenance research.
Evolution
From hinged backs (sometimes multiple, as in 'pair-cased' watches with an outer protective case) to screw and snap-fit backs, with sealed screw-down backs becoming standard for water-resistant sports watches in the 20th century.
Known variations
- Hinged case back
- Screw-down case back
- Snap-fit case back
- Exhibition (glazed) case back showing the movement
Identification for collectors
- Hallmarks, import marks and serial numbers stamped inside the case back are key attribution evidence
- An exhibition case back with a glass or crystal window allows movement inspection without opening the case
Common failure modes
- Perished gasket reducing water resistance
- Stripped or cross-threaded screw fitting
- Worn hinge on hinged backs
Photographs
Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.
Sources & references
- de Carle, D., Watch and Clock Encyclopedia
Where sources disagree, the disagreement is stated rather than resolved silently.