Precision Horology
Precision Horology


The clock really consists of two movements, one which operates the pendulum and one which operates the dial work. In a normal clock, both of these functions are all contained in one “movement” The movement operating the pendulum can be seen in the photographs at the top right and left. The pendulum is supported by a trunnion through which the pendulum rod extends. The trunnion is supported by a pair of cross spring suspensions (C-Flex). Rods, extending from the trunnion and perpendicular to the pendulum rod (see the picture below left) have small hardened steel pallets attached.Small sapphire weights  


All of return springs used in the movement are C-Flex bearings so that adjustment should never be needed.

are dropped alternately on these pallets to keep the pendulum in motion.  

The movement operating the motion work (hands) indicates mean time – hours, minutes and seconds – as well as sidereal time – hours, minutes and seconds. The 8 pinions and 16 gears gears are all driven from one ‘scape wheel which is impulsed by a specially designed form of solenoid. The solenoid receives an impulse once a second from the pendulum movement.

The dial is solid silver which has been chemically etched to form the chapter rings and numerals which have been filled with black enamel. All of the pivots run in miniature ball bearings to minimize friction.

The trunnion supporting the pendulums showing the two impulse arms with small circular hardened steel pallets.  This is the original version using knife edges which was subsequently changed  to x springs

(ABOVE)The dial movement showing both gear trains for mean and sidereal time. The impulsing solenoid is on the back plate and cannot be seen .

(BELOW) The hammer impulse mechanism.

When I designed the movement I used a program  called Delta Cad to lay it out.

Silver dial with large seconds bits . The  dial is quite perfect but the photo doesn’t show it