How to Set Up a Longcase/Grandfather Clock

How to Set Up a Longcase/Grandfather Clock

Ensure the case is level and standing firm. If the upper case is standing away from the wall, due to a skirting board maybe, it is advisable to find a suitable piece of wood to bridge the gap.

With 8 day clocks the movement is usually attached to a seat board, place the movement board on top of the case trunk cheeks and support the movement until the pendulum is in place as this will stop the movement toppling. 30 hour clocks seat boards are often separate and so the rope or chain and pulley will have to be passed through the centre slot and then put up onto the trunk.

Hang the pendulum, as shown in the sketch opposite, by putting the pendulum up through the trunk door and through the seat board, then through the crutch loop and locate the suspension feather into the slot on the back cock and seat the top block down into the notch.

Sliding on the hood, adjust the seat board from underneath until the dial lines up perfectly in the hood frame. Remove the hood again and, if screws are present, secure the seat board to the case. When the case is absolutely level allowing the pendulum to swing freely, it is recommended that the case is fixed to the wall through the hole in the back of the case.

In an 8 day clock be sure that the weight suspension lines are untangled and hold the line about one foot down from the board. Pulling it tight and maintaining tension place the winding key on the square and wind very slowly watching it feed onto the barrel grooves in the movement until the bottom of the loop and the pulley are towards the upper end of the door opening.

Without releasing the tension on the line to ensure there are no loops or kinks, turn over the pulley and place the line in the groove. Hang the weight on the hook. Repeat the same procedure with the other weight. In the case of a 30 hour clock; check that the rope or chain is correctly seated on the sprocket within the movement, turn the pulley up the correct way and hang the weight.

In Beat

Set the pendulum swinging and listen to the tick. If the tick is uneven then you will need to adjust the crutch (a) to set it ‘In Beat’ – a steady, even tick. If the tick is uneven the clock will usually stop. To adjust hold the pendulum bob in a central position move the bob to the right and then back to the left. If the longest gap to the tick is when the bob is swinging to the right then the crutch needs to be bent to the left and if the longest gap is when the bob is swinging to the left then the crutch needs to be bent to the right. Make small adjustments until you achieve an even tick. Make sure that the lower suspension block (f) is in a central position within the crutch loop (b). Bending the crutch arm (a) either forward or backwards to rectify.

Set the Hands

Move the minute hand only in a forwards direction stopping at each striking point to allow the full sequence to occur. Stop when the desired time is reached.

Check the Strike

Most 8 day clocks are rack striking where the sequence should not differ from the time. In some early clocks of 8 day or month duration the locking plate system was sometimes used.

Occasionally these may get out of sequence and a correction will be necessary: First remove the hood and look at the left hand side of the movement. On the very back plate or in front or behind the largest wheel, attached to the barrel, there will be a wheel without teeth but with notches cut into its circumference at uneven intervals. Resting on this locking plate circumference will be a lever, which must be raised and released to activate the strike. Continue to release the strike until the number struck coincides with the time.

For 30 hour clocks most are locking plate striking and will probably need correcting fairly frequently if allowed to run down. Finding the locking plate, use the same method of correction as described above.

Date Setting

There are three common types of date indication: centre date hand, a hand on a subsidiary dial or the date showing through an aperture.

If the date is in the correct 12 hour sequence then the centre date hands can be moved backwards or forwards manually during the day – at night for a few hours the clock will be trying to advance the date and if resistance is felt do not force the movement.

Subsidiary dials occasionally change every 24 hours although more commonly 12 hours when they are advanced half way. The hand can be moved manually but again, if any resistance is felt at all it should be left to another time as the clock may be trying to turn itself.

There are two common types of aperture date displays, a segmented wheel and a single figure. For those showing in a segmental aperture, the wheel usually turns through half a division every 12 hours and so at certain times it may not be moveable. Gently push the dial through the aperture in the direction of the figures, counting up until the correct date is reached.

For those showing a single figure through a square aperture; remove the hood and turn by revolving the date ring from the back. They can be moved backwards or forwards except when clock is driving the date itself.


If the clock is running fast or slow it will need regulating. Most longcase clocks can only be regulated via the pendulum – moving the bob up to increase the speed and lowering to decrease.

There is a nut at the bottom of the bob to adjust it’s position. It is advisable to hold the bob whilst adjusting to prevent the rod twisting and damaging the suspension feather. Start by moving it a turn or two in the appropriate direction and leaving it to run for a few days before deciding whether to further adjust. Repeat until the clock runs accurately.


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