400 Day / Anniversary Clock Maintenance

The 400 day or Anniversary clock is a precision instrument capable of very accurate timekeeping - if properly adjusted and looked after. Almost all other spring wound clocks require small adjustments to the hands each time they are wound up, which is usually every day or every week. Your 400 day clock will rum for a whole year with one winding and it should be anticipated that small adjustments to the hands will be required on occasions, though hopefully not too often!

The Pendulum

You will receive the clock with the pendulum locked to the frame or removed from its suspension attachment. It should remain locked or unattached until you are ready to set the clock in its permanent place. On older clocks with detachable pendulums, the hook at the top of the pendulum should be attached to the brass block at the bottom of the suspension wire. The hook normally goes over the pins projecting from the sides of the block. If a cover for the suspension wire is fitted it may have to be raised to gain access to the block. The bottom block may be loosely attached to the movement plate to prevent damage in transit. More modern clocks usually have a lever to lock the pendulum to the frame. Gently move the lever to release. The suspension wire that attaches the pendulum to the movement is not much thicker than a human hair and is easily damaged or broken. Take great care when attaching the pendulum, and adjusting the timekeeping. Moving the clock without locking or removing the pendulum can cause expensive damage. Never spin the pendulum round to 'wind' the clock or see the effect - it will make the suspension wire useless.

Starting the Clock

Once the pendulum is attached and free to rotate, gently push it round for about one complete turn from the stationary position and let go. It will rotate backwards and forwards faster than normal but eventually settle down to about ½ to ¾ of a turn in each direction. Rotating the pendulum more than a complete turn may have the effect of permanently twisting the wire into a corkscrew shape and making it ineffective.

Levelling the Clock

Anniversary clocks are designed to work best when placed on a stable, level surface that does not suffer any jarring or vibration. A shelf attached to a wall would be better than a table. A knock may stop the clock. If the clock has them, rotate the levelling screws up or down until the pendulum is centred.

Timing Adjustments

It is quite likely that the timekeeping will need adjustment after the clock is set up. Minor knocks during transit and the packaging will almost certainly have affected the position of the weights on the pendulum. Timekeeping is carried out on these clocks by moving the balls or pendulum weights in or out. As weights are moved outwards, the clock will slow down. As the weights are moved inwards, the clock will speed up. On clocks with balls there will be a serrated adjusting disk just above the balls. This will usually be marked with 'F - S' or 'A - R' (or just a '+' or '-'), standing for 'faster - slower' or 'advance - retard'. Moving the disc in the direction of the 'F' or 'A' or '+' will make the clock run faster and the opposite in the other direction. On clocks with a disc pendulum, the weights will be similarly marked. They can be adjusted using a key on the end of the rod that connects them. Turning the key in one direction moves both weights in or out simultaneously. Do not adjust the pendulum more than once a day to give the timekeeping a chance to settle down. As accurate timekeeping is approached very small adjustments will be required. It is better to start with the clock running too fast. In this way al the loose parts of the pendulum are seated and there is no slack. The clock may slow down as the mainspring unwinds and for this reason it is a good idea to wind the clock every 3 or 4 months rather than wait until the end of the year. It is also best not to fully wind the mainspring so that the key becomes solid. Leave a click or two so that the spring is not completely locked.

Setting the Time

Set the clock to the correct time by using the minute hand only, when the pendulum is at an extreme in its swing, or is locked. Do not touch the hour hand.

City Clocks Maintenance

At City Clocks we will be happy to advise you on your clock maintenance.

Contact City Clocks here or call us on 0800 78 345 87.

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