Marine Chronometer Winding Keys

Here are some examples of keys we have had made in the past.

This was a very small ratchet winding key for a marine chrononometer by Berthoud Freres.
 

Berthoud key

Side view of Berthoud key

A key copied from an original Earnshaw pocket chronometer, cased up as a marine chronometer c1820

A typical English chronometer key

This ratchet winding key was for an early marine chronometer by Parkinson & Frodsham. The original key is shown on the left and the new key is shown on the right.