Long Case Maintenance

Setting Up Long Case Clocks

There are two main types of longcase clocks, 8 day and 30 hour. The simplest way to tell is that 8 day clocks have winding holes through the dial and two weights hung on lines. 30 hour clocks have no winding holes and only one weight hung on rope or chain. For both types start by placing the trunk of the case in the position it is going to occupy.

Do not use any packing under the clock at this stage but get somebody else to hold the case throughout the setting up to prevent accidents. With 8 day clocks the movement is usually attached to a board, unravel the lines and place the movement board on top of the trunk side uprights and get your assistant to hold it. With 30 hour clocks the base board is 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 uprights.

Now with the movement still being supported, hang on the pendulum. Look at the drawing, then pass the pendulum up through the trunk door, up the back slot of the board, up through the crutch slot and pass the suspension spring into the slot of the back cock and seat the brass block down into the notch. Now that the pendulum is on, there is less likelihood of the movement falling forward.

The next stage is to slide on the hood. Manoeuvre the board backwards or forwards, from side to side, from underneath until the dial lines up perfectly in the hood aperture. Remove the hood again. With 8 day clocks, untangle the lines carefully and deal with one side at a time. The lines should be fully out and not tangled up around the wheels. Hold the line about one foot down from the board and pull it taut.

Place the winding key on the square and wind very slowly, about 6 turns, whilst keeping the line taut and watching it feed onto the barrel grooves. Without releasing the tension on the line follow it down to the bottom to ensure there are no loops or kinks, turn over the pulley and place the line in the groove. Then hang on the weight making sure the tension on the line is not released until the weight is in place. Repeat with the other weight. With 30 hour clocks, check that the rope or chain is correctly seated on the sprocket within the movement. Untangle the rest of the rope or chain following down to the bottom. Turn the pulley up the correct way and hang on the weight. At this point no packing has been used and your assistance is still supporting the clock. Packing should be of firm material that will not compress under the weight. First attend to the back to front movement of the case. Push back the case until the pendulum bob is still clear of the back and the weights are clear of the front door. The gap at the back of the clock needs support if the case is to be firm.

The ideal thing is a cork from a bottle cut down to the right height to suit the gap and glued to the back of the case. The front of the case can then be tightly packed against this cork to stabilise it. The case can of course be screwed to the wall to safeguard it. Now pack the side to side level until it is upright. For this it is sometimes better to go by eye, especially if you have a wall edge or window frame nearby as these are often not perfectly vertical. Now the case is secure, the pendulum can be swung to check if the clock is in beat. Listen to the "tick", this must be even in order that the clock continues to function. If the beat is uneven, the crutch arm has to be bent. To determine which way to bend it you must first decide which way the pendulum is swinging on the longest gap between ticks. If the longest gap is when the pendulum is swinging towards the right, the crutch arm must be bent towards the left (viewing from the front). If the longest gap is when the pendulum is swinging towards the left, the crutch arm must be bent towards the right. Trial and error will soon have it correct.

The suspension block should be in the centre of the crutch fork, adjusted by bending the crutch arm backwards or forwards. The hood can now be replaced and the clock wound and set to time. WINDING. 8 day clocks are wound once a week, usually with a cranked key in a clockwise direction of 14 turns. It is advisable to open the trunk door and watch the weights going up so that you can see how far you have wound. 30 Hour clocks are wound each day by opening the trunk door and pulling on the rope or chain, usually the back right hand side until the weight reaches the top of the case.

Hand Setting on Long Case Clocks

For most longcase clocks where only the hour is sounded, move the minute hand ONLY in a forwards direction pausing at each hour to allow the clock to complete its strike. For minor adjustments in a backwards direction, only move the minute hand between the figures 45 - 1. To move the hand back past the 60 may well damage the movement. For quarter chiming clocks, the clock must be allowed to sound each quarter. For minor adjustments in a backwards direction, only move the minute hand between the figures 7 - 1, 22 - 16, 37 - 31 or 52 - 46 minutes.

Strike Correction on Long Case Clocks

Most 8 day clocks are rack striking and so the sequence should not differ from the time. However in early clocks of 8 day or month duration the locking plate system was sometimes used which may become out of sequence at some point. To correct these, 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. This lever quite often has a projection sticking out from its arbor which is easy to see and get to. For 30 hour clocks most are locking plate striking and will probably need correcting fairly frequently if allowed to run down. The locking plate should be easily found. Use the same method of correction as described above with 8 day clocks.

Date Setting on Long Case Clocks

Three types of date are in common use. The centre date hand, the hand on a subsidiary dial or the date showing through an aperture. Centre date hands can be moved backwards or forwards manually, except when the clock itself is trying to turn the date over a period of a few hours at night, if the clock is set in the correct 12 hour sequence. Hands on subsidiary dials sometimes change every 24 hours or quite often every 12 hours of half a division. The hand can be moved manually but if any resistance is felt at all it should be left to another time as the clock may be trying to turn itself. Two types of aperture dates are used. 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. The easiest way is to gently push round the dial through the aperture in the direction of the figures, counting up until the correct date is reached. Those dates showing a single figure in a square aperture are turned by revolving the date ring from the back of the dial after removing the hood. They can be moved backwards or forwards except when clock is driving the date itself.

Regulation of Long Case Clocks

The only way of regulating for most longcase clocks is by the pendulum itself. The nut at the bottom of the bob is screwed up to the right (clockwise) to make it go fast and left (anti clockwise) to go slow. It is advisable to hold the bob whilst doing this to prevent the rod being twisted and damaging the suspension spring. It is fairly common that the thread or nut is very worn and slips down, so watch for this happening and if this is so, get the pendulum repaired by a qualified horologist to prevent it happening again.  Longcase clocks have many different variations including musical automata and lunarwork etc. For lunar dials showing in the arch the disc can be revolved manually from the back with hood removed. The lunar date has no connection with the actual date. A lunar month consists of 29 1/2 days beginning from the no moon position. For other types, contact the shop the clock was purchased from or a qualified horologist such as Jeff Rosson from City Clocks.

City Clocks Maintenance

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

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