What Makes Grandfather Clocks Move?

A very important contribution to the time-keeping process was the Grandfather clock, invented by William Clement in 1680. Its popularity grew after American songwriter Henry Clay Work wrote the song “My Grandfather’s clock”, unknowingly giving the invention its name. But how does a grandfather clock work?

A Grandfather clock can operate due to the pendulum that is present within it. The pendulum is a vertical rod with a weight at the end of it. The pendulum moves in a back and forth motion and is attached to a gear that directs the pendulum and keeps it swinging.

Grandfather clocks are pendulum clocks, yes, but not all pendulum clocks are Grandfather clocks. Grandfather clocks do not run on electricity but are mechanical and need to be wound up from time to time. Let’s take a deeper look into how the Grandfather clock operates.

Grandfather clock

How Do Pendulums Work?

The mechanics that power the Grandfather clock can be a little confusing, but it’s an interesting process regardless. The pendulum in the clock is attached to a weight that falls and rises as that pendulum swings back and forth. That weight acts as a source of potential energy and is connected to a gear that converts that potential energy to kinetic energy.

As the pendulum swings, two forces (friction and air resistance) steal a little energy from the pendulum, slowing it down a little. Despite this, the pendulum doesn’t stop, thanks to that gear that directs its movement. It takes the same amount of time for a pendulum to complete a swing every time, which is known as isochronism.

It sounds like a lot of physics, but isochronism is the reason Grandfather clocks are efficient timekeeping pieces.

A typical Grandfather clock has five main parts necessary for its operation:

  •  A weight that acts as a source of potential energy (a power source of sorts)
  •  A gear that is attached to the weight, transforming potential energy from said weight
  •  An escapement that acts as a locking mechanism that regulates how fast the weight falls
  •  The pendulum, the time-keeping mechanism
  • A traditional clock face called a dial

Types of Grandfather Clocks

The parts that regulate the mechanical bits and run the operations of the clock are called a movement. A movement controls parts like the minute hand, the hour hand, the chime melody of the clock, and general time-keeping as well. There are three types of Grandfather clocks based on the kind of movement that powers the operations.

Chain-driven Grandfather Clocks

These clocks have a chain that holds the weight in the right position. There are three chains with three weights at the end and each has its specific purpose. One controls the melody of the chime, while the other powers the pendulum, and one powers the strike.

Remember that Grandfather clocks need to be wound up every once in a while? Well, chain-driven clocks need to be wound up once a week. To power the clock, the weight in the clock drops down and needs to be taken back up again. Winding it up requires pulling the chains so the weights can come up again.

Chain-driven clocks are inexpensive to produce so they are typically found in cheaper grandfather clocks.

Cable-driven Grandfather Clocks

Just as the name implies, these Grandfather clocks use cables instead of chains to keep the weights in position. Similar to chain-driven clocks, these possess three cables with three weights. One handles the hour strike, the other powers the melody of the chime, and the last powers the pendulum.

Cable-driven clocks aren’t exempt from being wound up. They need to be wound up by the end of the week as well but instead of pulling on the cables, they have a key for the purpose.

Quartz battery-operated Grandfather clocks

This type of clock is convenient in the sense that it doesn’t need to be set up or wound up. Quartz crystals are used to produce an electronic oscillator that powers the clock. It is a newer way of powering Grandfather clocks and you can go a year without needing to change the battery within this clock. 

How Often do Grandfather Clocks Need to be Wound Up?

We’ve established that a Grandfather clock has parts that you need to wound up. If they are not wound up, they can stop working. Grandfather clocks can either be one-day clocks or eight-day clocks.

One Day Clocks

One-day clocks need to be wound up every day. They have one single weight and it is responsible for driving the timekeeping and strike of the clock. These clocks are cheaper than their counterparts so they are great for people who are looking for cheap clocks.

Eight Day Clocks

These need to be wound up every week. These use two weights instead of one weight like the one-day clocks. One drives the pendulum and the other one regulates the strike.

Eight-day clocks have a strike that sounds like a bell and they have a pair of keyholes on either side of the dial. These keyholes are what enable the clock to be winded up.

What do I do if my Grandfather Clock Stops Working?

Grandfather clocks are thought to be fragile because they are valuable antics but this is a misconception. Grandfather clocks are, in fact, quite durable. Sometimes though, the clock can be bumped accidentally, or perhaps it was moved from its usual position and it stopped working. Here are a few things to look out for if your clock stops functioning;

  • Look at the dial and ensure the hands aren’t touching each other or hanging into any part of the dial.
  • Check if the pendulum is swinging freely and is not obstructed by the weights of the clock.
  • Listen to the ticking sound the clock is making. There has to be an even amount of time between each tick and tock. if it is uneven, then the clock is offbeat and will need correcting.

If you have done any of this and the clock still isn’t functioning properly, then a professional might need to be called in.

How much is my Grandfather clock worth?

Many Grandfather clocks display unique features and craftsmanship which can raise their value. Grandfather clocks can be valued according to how often they need to be wound up.

Clocks that only need to be wound up once a week (Eight-day clocks) are sought after more than their one-day counterparts due to how less frequently they need winding. An Eight-day clock can fetch between $800 to $1200 or more if the wood it was made with is mahogany or oak. One-day clocks go for lower and can fetch between $600 to $800.


Grandfather clocks have fallen out of favor in terms of use. Most people prefer to use electric clocks nowadays. Despite this, Grandfather clocks are still being made and can still be appreciated for their beautiful craftsmanship and their nostalgic value.

Grandfather clocks are considered to be valuable antiques so they need to be cared for properly. A Grandfather clock that has been taken care of properly can last years, generations even. If your Grandfather clock is in good condition, its value is raised. There are many intricate parts to a Grandfather clock so it is important to be extremely careful if you need to move your clock around.

That being said, perhaps Grandfather clocks might make a comeback and be useful for things other than their aesthetics. It would be a shame to let such an accurate, consistent timekeeping piece be forgotten.

Check out our article on where Grandfather Clocks originated for more information.

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