The quarter strike
fly arbor has mounted to it a standard French design for it's warning and locking detent
pin configuration. The warning detent pin was broken off (1). This was curious since this
pin is normally never under any appreciable stress. The locking pin, while unlikely, could
conceivably be broken from too much force at stopping the fly arbor. What made this repair
interesting was the pin had to have a square profile. The clearances for this pin to
correctly slip past it's mating pin on the quarter strike locking lever was critical. The
material was music wire (2) - a very hard material, so grinding (3) was necessary to shape
the square profile. Also a slight taper was given to the work so it would properly mate
into the original taper hole. A cutting wheel (4) was needed to part the work. The piece
was set and tapped into place as was done originally (5 & 6). The over length was then
ground to size (7) and the part is finished (8) and matched to it's twin on the hour
strike side (9). After initial trials it was discovered why the warning pin had broken
off. The quarter strike lever was a bit misshapen. So when the warning sequence was
finished it allowed the pin to just slip under the lever pin (which is more robust) and
catch there instead of continuing past to begin the quarter striking sequence. As the
lifting cam continued to raise the strike lever the more robust lever pin exerted pressure
on the finer warning pin, breaking it off. It was fortuitous that I scoped out this
sequence of events instead of letting the clock run or the new pin would have been
promptly broken off again! These observations and subtle adjustments were needed in many
places on the movement. Failure of prior repairers to fully appreciate this resulted in
the patchwork of shims and extra remontoire weight.
Other miscellaneous repairs and adjustments included straightening bent spokes on the
remontoire locking wheel (1). Replacement of all hammer pull wires with new straight brass
(2). The old wires were of differing materials and badly bent up in many places, many if
not most were already replaced at some point in the past.
Many of the screw heads had mangled slots from being over-driven with inappropriately
sized screwdrivers. These were 'dressed'. A process where the slot edges are smoothed and
straightened. The the screw head is then polished and lacquered.