PENDULUM CLOCK GUIDANCE

Always remove the pendulum before moving a clock. If this is not practicable you should tilt the clock forward to allow the pendulum to rest against the body of the movement. Some clocks have a special clamp to secure the pendulum. If this is a feature of your clock, do remember to use it. Suspension. Pendulum and Escapement repairs are usually rather expensive.

When winding the types of clock which are "sandwiched" into the case - many French and American ormolu, slate, marble clocks are like this - it is important to prevent the whole movement turning in the case. Even very small alterations will put the clock out of beat and it will not run properly. Indeed, so important is this that whenever a clock is moved to a new position - or moved carelessly or accidentally - it is necessary often to re-set the beat.

During the workshop service the clockmaker will have made all the necessary adjustments whilst your clock is standing or hanging in a stable, vertical, level aspect and it is necessary for these conditions to be repeated in your home. There is no practical alternative that does not require the attention of the horologist.

The main factors which affect the operation of a pendulum clock and its timekeeping are:

Position - Temperature - Vibration

If your pendulum clock is giving trouble there are some things you can do yourself to try to correct matters. However, you must be aware that some parts of even very large clocks are quite delicate. Repair can be difficult even for the skilled craftsman and replacement parts which have to be made are expensive.

Your clocks always react badly to vibration, draughts, cats, children and vigorous dusting. A mantle type clock should be placed on a solid level shelf or on a heavy piece of furniture. Wall clocks should be hung from secure fixings. Packing should be used if the wall is uneven. Stabilisers are often a good idea and are obtainable from your horologist.

Long case clocks were designed to stand on solid floors. Generally that’s all they had in 1750! Fitted carpet and carpet gripper make your clock unstable. The case should be secured to the wall vertical in every aspect. Most longcase clock cases have convenient holes

made by previous owners.

Listen carefully to your clock:

A clock which is out of ‘beat' will stop eventually. Furthermore the condition can give rise to uneven wear on

the escapement assembly. When 'in beat' the pendulum moves an equal amount either side of it’s centre resting point. The SOUNDS of alternate ticks will differ, but it is TIME with which we are concerned, not sound If the distance [times] each side of the centre point are not equal, proceed as follows: [with extreme care as suspension springs and escapement teeth are fragile)

1. Make sure your clock is secure and level side to side and front to back

2. Stop the pendulum and allow it to come to its rest position.

3. Hold gently but firmly and move the pendulum to the right and to the left until ticks are heard

4. Observe the relative distances from the centre point.

5. GENTLY!!! bend the pendulum CRUTCH in the 'shorter-to-tick' direction.

6. Swing the pendulum and observe the result. Remember, SOUND is unimportant

7. Repeat the above until the INTERVALS between ticks are regular.

Most pendulum clocks will respond to this treatment but the 'out of beat' condition may not be the primary problem - you may need to call your clockmaker after all.

At the bottom of the pendulum. under the Bob is the Rating Nut. Turning this nut raises or lowers the Bob, making the effective length of the pendulum either longer or shorter.

Do not alter the pendulum more than once in every 12 hours or thereabouts. Make small adjustments each time, keeping a note of the changes and the resulting effect. Control your experiments against the National Time Signal.

Be aware that the power output of even a brand new spring is not constant as it unwinds. If your clock is running slow. it may be necessary only to wind it up rather than adjust the length of the pendulum.

There are many variations on the escapement. This is the arrangement whereby one tooth of the Escape Wheel, and ONLY one tooth at a time, is allowed to pass or 'escape' through the Pallets. This is the bit that makes the clock 'tick'. It is impossible to cover in these notes all the variations of escapement. Some pendulum systems have friction joints, others have a screw adjuster. Some require preliminary attention to the escapement. Your horologist will be pleased to explain how your clock works. Many French and some German and American movements have a small square-ended steel protrusion above the '12' which is a fine adjustment for effective pendulum length. The square end is suited to a Brocot Key or an old fashioned pocket watch key. Usually, turning to the right will make the clock run faster and to the left. slower.