I dont get out much. By chioce. So new years eve for me is spending time hanging around the house with my sons with nothing particular to do. But there was a clock on the jigg. Its been annoying me. The thing would not activate on its first quarter chime but perfectly on the other three inducing the auto top of the hour reset system working.
Why let something like that run into the new year. Tools out. Diagnostics head on. Method devised and to it!.
I stripped the clock face down and had a look at the components for signs of exagerated wear. If theres a problem wear logically has to be the cause so if you find the wear you can trace the fault. there was no wear but it did become apparent that the cam lift height on each of the quarters was a step higher by a small amount. This is not normal. Its not necessary. The purpose of having one lifting cam much larger off the canon pinion is so that within 1 hour 45 minutes a clock will find its top of the hour chime sequence automatically. Its not a feature you find on grandfather clocks but this clock is a longcase from around 1930 and the invention of the auto reset came about popularly in early and mid 20th century mantle clocks.
This clocks employed the same principle of auto reset but improved upon it. Each lifting pin off the canon pinion was one step further away from the centre meaning that the lift on each quarter increased. Put simply the lift cam for the first quarter will not lift high enough to activate the second. The same aplies to the relationship between the 3rd and 4th meaning the clock will reset to the correct chime sequence in a maximum of 45 minutes which doubles the performance of the feature. Its actually less necessary to employ this feature on weight driven clocks because chimes going out of sequence is usually a mantle clock problem caused by one spring running down more quickly than another to its force equilibrium point with gear friction . In this instance the clock keeps going but the chime spring no longer have the power to drive the hammers. Its is therefore a very nice touch to go to a full quarter chiming longcase and improve upon the fundamental contemporary design.
Once this was understood the fix was applied and finished up about 20 minutes ago. The clock is running with a strong pendulum arc and I can just tell its good to go and finished.
Here it is. Its a really nice example of what it is and a great clock. The case has an simple conservative body with a beautifully arched top. Great lines generally. If I remember Ill post a picture of it installed. Its just chimed quarter to, so time to go but I just want to say…
Thanks everyone. Its been fun this year, lots of new things have happened and Ive met a lot of really nice interesting people with decent taste and an appreciation of historical engineering.
Quick addendum. It struck exactly, to the second, on midnight. This is and excellent omen. Probably. Or its and excellent clock or both.