I have a Schmid-Schlenker mantle clock from the early 1980’s that I’m attempting to regulate. I wonder what is the correct beat time for this movement. There are markings stamped 2/25 on one of the plates -does this indicate the beat time in some way?
The bpm may only be determined by disassembling the clock and doing the math according to the number of teeth/leaves in the train. Otherwise, you'll just have to play with the rating nut on the pendulum until you hit the sweet spot. The 2/25 markings do not seem to refer to beats per minute, but I could be wrong about that.
In another clock of mine, a French clock, markings on the plate refer to pendulum length and one can determine beat time from that. I thought the 2/25 marking might infer some similar meaning. It’s there for a reason.
The second picture shows the clock in partial disassembly. That’s the reason parts are missing.
I agree, but exactly what that number means may remain a mystery ... it could be a date, or model code?
Note, in the time it takes you to figure out what the rate is, you can easily rate it in the traditional manner.
Also, when and if you do get a good number, it takes a certain amount of time to bring the clock to the approximate rate. You will still need to fine tune it (week to week) usually over a few weeks using the traditional method.
I'm a slow typer, I could have rated at least two clocks (real time spent) in less time than it took me to type these two replies! Not kidding. Willie X