UK Specialist in the Service and Restoration of Marine Chronometers
MAKING JEWELS FROM SAFFIRE ROD
MAKING AND REPLACEMENT OF IMPULSE AND LOCKING STONES
THE TYPSY KEY
Every chronometer should have a tipsy key. These keys work by an internal ratchet
which allows the instrument to be wound only in the correct direction which in most
cases is anti-clockwise.
The importance of this cannot be stressed enough as to apply force to the fusee in
the wrong direction can result in broken teeth on the maintaining ratchet, damaged
fusee clicks and ratchet teeth and worst of all damage to the detent and escapement.
The fusee key is designed to ratchet or slip if pressure is applied in the wrong
direction thus protecting the instrument.
I often see the results of using the 'wrong' key. I can make tipsy keys of period/maker
design to fit the chronometer and box.