Skip to content
The Encyclopedia of Horology

Component record · Case

Movement Clamp

Partially verified

A screwed clamp holding a movement in its case.

What it does

Retains the movement securely without stressing the plates.

How it works

Two or more clamps bear on the plate edge; over-tightening distorts the plate and affects timekeeping.

Evolution

Replaced case screws in many twentieth-century designs.

Known variations

  • Clamp fixing
  • Case screw fixing

Identification for collectors

  • Clamp marks on a plate edge show past fitting and sometimes a change of case.

Common failure modes

  • Bent clamps
  • Stripped clamp screws

Diagram

bezelcrystalback and cuvetteband, bow and pendant
Schematic: case construction. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. de Carle, D., Practical Watch Repairing
  2. de Carle, D., Watch and Clock Encyclopedia
  3. Daniels, G., Watchmaking

Where sources disagree, the disagreement is stated rather than resolved silently.