How to Regulate the Minute Hand on a Grandfather Clock

A grandfather clock that's run by weights can keep very accurate time, but you need to adjust it first. The speed of the pendulum regulates the movement, so by sliding the weight of the pendulum up or down, you can regulate the clock to run faster or slower.

Difficulty: Easy

Instructions

1. Before regulating the cock, check that the hands aren't rubbing against the face or glass case, or against each other when they cross. If a hand is rubbing, bend it very gently until it's no longer touching whatever it's rubbing against. Also make sure the clock is level. That's usually not a problem for a grandfather clock that sits on the floor, but a pendulum clock that hangs on the wall may need to be adjusted by placing a carpenter's level along the side and front of the case, and moving the clock until it's level. A clock may still keep good time, but the pendulum will swing more evenly when it's level, and if it's too far out of level leaning forward or back, the pendulum may drag.

2. Now you can regulate the hands to run slower or faster by adjusting the weight or bob of the pendulum. That's the metal piece at the bottom of the pendulum, which is usually a disk a couple inches in diameter. It may have a screw or nut to adjust it up and down the rod.
   
   If the clock is running slow, move the pendulum weight up the rod a short distance. If it's running fast, move the weight down. Don't worry about the exact amount you move it, for now. This is a process that's easier to do by trial and error!

3. Start the pendulum swinging again, set the hands, and compare the grandfather clock to an accurate clock in an hour. If it's still too fast or slow, adjust the pendulum weight again, to slow it down or speed it up.

4. Repeat until the clock is running on time for an hour. If you want to set it more closely, check it again in a day, and make even smaller adjustments. A well oiled and regulated grandfather clock can keep time surprisingly accurately.