Tools · pendulum clocks

Why has my clock stopped?

A step-by-step troubleshooter for grandfather (longcase), bracket, wall and mantel clocks with a pendulum. Choose what the clock is doing and work through the checks in order — the simplest and commonest causes come first, and the checks that need a clockmaker are marked.

What is the clock doing?

It stops after a few minutesUsually set-up: beat, level, pendulum.It runs, then stops after hours or daysSomething touching, a weight, or a tired movement.It will not start at allPower, pendulum or hands.It does not chime or strikeSettings and the chime weight first.It strikes the wrong hourThe hour hand has slipped.It chimes at the wrong minuteThe minute hand is not where the chime thinks it is.It runs fast or slowRegulate with the rating nut, in small steps.It ticks unevenly (tick… tock)Out of beat — see the beat checker.

Check in this order

It stops after a few minutes

Is it in beat?
The commonest reason a clock stops after it has been moved, dusted or wound. The escapement must release equally far either side of the pendulum's centre; if not, the tick and tock are uneven and the swing dies away.
- Listen with your eyes closed: tick and tock should be evenly spaced. Use the beat checker on this page to measure it.
- Many modern movements set their own beat: swing the pendulum well past its normal arc to one side and let go; the crutch slips on its friction clutch and settles.
- Otherwise stop the pendulum and gently bend the crutch (the arm that drives the pendulum) a few millimetres to one side, or turn the beat-adjusting screw if it has one. Restart and measure again: if the beat got more even, carry on in that direction; if worse, go the other way.
Measure the beat with your taps ↓
Is the case standing level and firm?
A case that leans or rocks moves the escapement's centre away from the pendulum's natural rest point — the same fault as being out of beat — and a rocking case absorbs the pendulum's energy.
- Look from the side and the front: the pendulum rod should hang parallel to the case back. Put thin wedges under the feet until it does.
- A longcase clock on carpet or a wooden floor can rock as people walk past; many are screwed to the wall through the backboard for this reason.
- Once level, check the beat again — levelling often changes it.
Is the pendulum hung correctly?
After a move the pendulum is often re-hung so that it misses the crutch, or with its thin suspension spring kinked or broken. It may then swing for a while from your push and stop.
- With a torch, check that the pendulum rod passes through the crutch's slot or loop and that the top hook sits squarely on the suspension post.
- Look at the suspension spring (a short, thin strip of steel at the top): it should be straight and flat. A bent or cracked spring needs replacing — an inexpensive part a clockmaker can fit.
- Make sure the pendulum is the one that belongs to the clock; a wrong pendulum will not keep time even when it runs.
Is anything touching?
The pendulum and the hands have very little power. A pendulum brushing a weight, a cable or the case back, or a minute hand catching the hour hand or the glass, is enough to stop the clock — often at the same time each day.
- Watch the pendulum bob pass the weights: when a weight is level with the bob they should not touch. If they do, turn the weight or move the case slightly away from the wall.
- Note when it stops. Stopping at the same time of day suggests the hands: the minute hand passing over the hour hand, or touching the glass or the dial.
- Hands should sit parallel to the dial with a small gap between them. A bent hand can be eased straight by hand, but do not force the hour hand, which is a friction fit.

Beat checker

Is my clock in beat?

Stand close to the clock and tap the button (or press the space bar while it is selected) exactly on every tick and every tock, for at least 13 taps. The checker compares the gaps after each tick with the gaps after each tock. Taps are timed on this device only; nothing is recorded.

0 taps — 13 more needed

The result appears here after 13 taps. A pause of more than four seconds starts a new reading.

The parts you will be looking at

Open the trunk door of a longcase clock, or the back door of a bracket clock, and you will see most of these. Handle the pendulum by its rod, not the bob, and lift it off before moving the clock.

Part	What it does
Pendulum	The swinging rod and bob that sets the rate. Its length decides the beat: about 99.4 cm for one beat a second.
Crutch	The arm behind the movement that gives the pendulum a small push each swing; bending it sets the beat.
Suspension spring	The thin steel strip the pendulum hangs from. Easily kinked when a clock is moved.
Rating nut	The nut under the bob. Raise the bob to gain, lower it to lose.
Weights	Drive the trains of a weight-driven clock: time, strike and (on three-weight clocks) chime.
Silence lever	Turns the chime or strike on and off; on some clocks it also selects the tune.

Before you move a clock

Unhook the pendulum and the weights (note which weight came from which side), and wedge or tie the cables so they cannot jump their pulleys. After the move, level the case before re-hanging the pendulum, then set the beat. Most "broken" clocks after a house move are simply out of beat.

Questions people ask

Why does my grandfather clock keep stopping?

Most often because it is out of beat (the tick and tock are not evenly spaced) or the case is not level, especially after it has been moved. Next most common: the pendulum touching a weight, the hands touching each other or the glass, a weight not wound or in the wrong place, and finally a dirty or worn movement that needs servicing.

How do I put a pendulum clock in beat?

Listen for an even tick-tock. If it limps, level the case first; then either swing the pendulum wide to one side (many modern movements adjust themselves this way) or gently bend the crutch a little to one side and listen again, continuing in whichever direction makes the beat more even.

Why won't my grandfather clock chime?

Check the chime/silent lever first, then that the chime weight (usually the heaviest, on the right of a three-weight clock) is wound. Some modern movements silence themselves at night. If the chime stopped while the hands were being moved, wait for the next quarter or move the minute hand gently forward to it.

Which weight goes where on a grandfather clock?

On most modern three-weight movements, seen from the front: left for the hour strike, centre for the time, right for the chime, and the right-hand one is normally the heaviest. Weights are often marked underneath. Older two-weight clocks have one weight for the time and one for the strike.

Why does my clock strike the wrong hour?

Usually the hour hand has slipped. Count the strikes, then turn the hour hand on its own to that hour; it is a friction fit. Older clocks with a count wheel may need the strike released a few times until it agrees with the hand.

Can I turn the hands backwards?

On many modern movements, yes; on older chiming clocks it can jam the chime. Moving the minute hand forward only, pausing at each quarter for the chime, is safe on every clock. To put a clock back, stop the pendulum instead.

How often should a grandfather clock be serviced?

Many clockmakers suggest a full clean and oiling roughly every five to ten years, sooner in a dusty or centrally heated room. Signs it is overdue: it stops when the weights are low, runs only when pushed, or strikes slowly.