TIMEKEEPING ISSUES
A note about timekeeping with the stock pendulum that is designed to be used with a given clock: Shorten this pendulum and the clock will run faster. Lengthen this pendulum and the clock will run slower. In other words turn the adjusting nut to your left to make the pendulum longer so the clock will run slower. Turn the adjusting nut to the right to make the pendulum shorter so the clock will run faster. One full turn. (Make sure the pendulum actually moves when you do the adjusting; sometimes the part inside the pendulum bob is loose and slips when you try to make an adjustment.) Make note of the time. Check the clock in 2 days. Make the adjustment again of one full turn. Make note of th time Check the clock in 2 days. Keep this up until you have done two things: Acquired a record of how many turns it takes to make a specific change in timekeeping ; and have the clock keeping time. A useful formula for calculating timekeeping data is: L = Li*(1±E/R)². L is correct length, Li is incorrect length, E is error in hours, and R is length of test run in hours.
Now this interesting question. What do you compare the clock to ? You would be surprised what I have found customers comparing their clocks to for timekeeping adjustments. The TV (the TV is the best one I have heard), a digital clock,( a digital clock without a number for seconds will drive you nuts if you want to get more than plus or minus 1 minute accuracy), the clock on the town hall, my cuckoo clock, the computer clock, the clock in my car, the list goes on. My point here is be sure you are using an accurate comparison, and only ONE clock for comparison, or you will be spinning your wheels – – literally! The big mistake most people make is assuming that all clocks in the realm of TV, government, business, and technology, are somehow all set to exactly the same time, so they compare to a different clock every time they make an adjustment. If you are a clock repair technician, this is obvious to you, but to the average person it may not be so obvious.