It is not uncommon for a clock mechanism to be separated from its original case. Wooden cases deteriorate due to moisture, heat, glue failure, abuse and accident. Metal cases rust, oxidize, break or fall apart due to joint failure. Stone cases fall apart due to adhesive failure and accident.
As a result of these situations many orphan clock mechanisms are found.
Replica cases can be made consistent with the period of the mechanism.
1. English lantern style mechanism / hooded wall clock, c.1740
2. Sylvester 400-day clock mechanism, c.1915
3. English long-case mechanism, c.1760