Calibrating a Mechanical Clock

Calibrate your mechanical clock to make it tell time correctly.

A mechanical clock utilizes a mechanical mechanism in order to keep time. The mainspring in a mechanical watch has to be wound from time to time in order to keep the watch calibrated and telling the correct time. Many modern watches aren’t mechanical, but instead are electronic; older watches and clocks, like grandfather clocks, are usually mechanical. Mechanical clocks may also be referred to as “wind-up clocks,” because of the spring and mechanism inside the clock.

Instructions

1. Move the minute hand clockwise to set the clock to the correct time. Make sure not to move the hour hand, which could damage the clock internally.

2. Watch the clock over one week’s time to see if it’s running too slowly or too fast. Keep an eye on the time in comparison to time that is known for sure to be accurate, like a cell phone or the weather channel on TV. If the clock is running too slow or too fast, turn the adjustment nut on the clock to the left to slow it down or turn it to the right to speed it up.

3. Wind the clock. Repeat this every week, on the same day of the week and at approximately the same time. Some mechanical clocks require a clock key in order to wind them.

4. Adjust the clock’s moon dial if the clock has one. The moon dial will keep track of the different phases of the moon. Adjust the moon dial by first finding out the date of the last full moon and then moving the picture of the full moon to that date.

Tips & Warnings

• Before calibrating your mechanical clock, make sure that you have the correct time. Check your phone or computer, which often has the time set by a cable or wireless company, making the time the most accurate.

• Check to see if the clock has an automatic chime. If so, make sure that’s it’s set to either “Manual” or “Off” before setting the clock. Leaving the chimer turned on could cause damage when the clock’s time is being moved forward.

• When a clock key is inserted, the motion to turn it should be smooth. If you find that it’s difficult to turn it or it feels like it’s getting stuck on something, don’t force it, which could damage the interior of the clock. It’s best to call a professional, who can come and take apart the clock to see what’s wrong internally.

References

• Chronocentric: General Wristwatch Troubleshooter
• Time Zone: Mechanical Watch FAQ V1.0
• Horology Zone: How to Adjust the Accuracy of a Mechanical Watch