Roy C Harris FBHI
Home History Buying Service Profile Archive Contact Links

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.

MAKING ESCAPEMENTS