Escapement Testing - 6 Ticks
Another reviewer has notices that there is a 6-tick pattern:
Tick 1 (Phase =0.0): A bit faster
Tick 2 (Phase =0.2): Right on time
Tick 3 (Phase =0.4): Faster
Tick 4 (Phase =0.6): Right on time
Tick 5 (Phase =0.8): Sometimes on time, but sometime slow
Tick 6 (Phase =1.0): Always slow
(Repeats)
This is notable because it is the period of time it takes to advance one tooth in the first-to-second arbor gear mesh. I’ve compiled a list of tick periods to keep an eye on, since the period of the irregularly often indicates the source of it.
I’ve developed an algorithm for identifying the frequencies of variation, which I can run the audio recording through to generate a spectrogram (see below). The 6 tick (and 12, 18, etc. harmonics) are very plainly visible. This is fairly damning evidence that the 10T-75T gear mesh is the culprit, so I’ll steer the investigation there next!
More information on NAWCC Forum post on this subject:
