Operational Guides
Grandfather Clocks
Summary:
Grandfather clocks—also known as longcase or tall-case clocks—are floor-standing timepieces built around long pendulums and weight-driven movements. Their height allows for slow, stable pendulum swings, giving them excellent timekeeping when properly set up and maintained. Identifying features include a tall wooden case, a long pendulum, one to three hanging weights, and often a multi-chime system.
Key Identifiers:
Tall Wooden Case
Grandfather clocks typically stand 6–8 feet tall. The case includes:
Hood/Boninet: Removable upper section housing the dial and movement.
Trunk: The center section where the pendulum and weights operate.
Base: Lower section adding stability and weight.
Long Pendulum
A metal or wood-bodied pendulum swings within the trunk.
Lyre pendulums have decorative rods and bobs.
Plain pendulums use a simple rod and disk bob.
Pendulum length directly controls timekeeping.
Hanging Weights
Grandfather clocks use two or three weights depending on the movement:
Left weight: Runs the strike train.
Center weight: Runs the timekeeping train.
Right weight: Runs the chime train (if present).
Mechanical Dial Features
Common dial elements include:
Moon dial or rotating lunar disc
Chime selector (Westminster, Whittington, St. Michael, or silent)
Strike/silent control
Second hand on some movements
Operational Guide:
Placement & Leveling
Proper leveling ensures accurate timekeeping and reliable striking.
Place the clock against a firm wall.
Level side-to-side and front-to-back using shims as needed.
Confirm that the pendulum swings evenly without rubbing.
Step 1:
Installing the Pendulum
Hang the pendulum onto the suspension leader or crutch post.
Make sure it hangs freely and is not twisted.
Step 2:
Hanging the Weights
Weights must be hung in the correct positions:
Follow the L–C–R markings on the chains or cables when present.
Confirm chains/cables seat properly on their pulleys or sprockets.
Gently raise weights to avoid jump-off or slack.
Step 3:
Starting the Clock
Give the pendulum a gentle push to one side and release.
Listen for an even tick-tock rhythm.
If uneven, adjust by slightly bending the pendulum crutch in the back to shift the pendulum left or right until the beat becomes balanced. Modern movements typically have an auto-beat verge.
Step 4:
Setting the Time
Move the minute hand only, and move it forward, pausing at each quarter-hour to let the chimes or strike complete.
Never force the hands backward unless the manufacturer specifically allows it.
Step 5:
Chime & Strike Operation
Most clocks play melodies on the quarter hours and strike the hour count on the hour.
Use the chime selector to choose the melody or silence.
The clock may require one full hour cycle to fully synchronize if it was stopped.
Step 6:
Regulating the Speed
Adjust timekeeping using the pendulum bob:
Lower the bob to slow the clock.
Raise the bob to speed it up.
Make changes in small increments (1–2 turns) and allow 24 hours to observe results.
Step 7:
Winding
Weight-driven grandfather clocks wind by:
Pulling down chains (chain-driven), or
Cranking the winding arbor with a key (cable-driven).
Wind each train until the weight nears the top, without forcing.
Step 8:
Routine Maintenance
Light dusting of the case and dial
Ensure chains/cables are free of twists
Have the movement professionally cleaned and oiled every 5–10 years
Avoid moving the clock with weights or pendulum attached