clock & barometer repairs
 
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setting up your clock

There's a lot here because it covers different types of clock. Please read through everything first and then return to this page to study the parts in sequence when you're ready to set it up. To make it easier to navigate, you can jump straight to the section you want by clicking on one of these headings:

 

 

You'd probably do well to bookmark this page so that you can return to it again later but if you've bought your clock from me, I usually include a hard copy of some instructions specific to each clock when I pack it.


 

LOCATION: Before fitting the pendulum, decide where to display it.

Carriage clocks are like mechanical watches in that they have a balance wheel (platform) escapement and so will run in any position, even lying on the back seat of a car (they were designed for travelling so they can tolerate movement). Any clock with a balance wheel is easily identifiable as, unlike the rest below, they have no pendulum. All these clocks are easy to site but avoid window ledges - if the sun doesn't harm any woodwork first, one day you might find it has been stolen. Also avoid side tables which get knocked and any low position on a level with wagging tails and young inquisitive fingers.

Mantel clocks with a pendulum on the other hand like rigidity, especially 400-day clocks. And they don't like vibration. So avoid any unstable surface like the television, a table on a carpeted floor or any furniture standing on loose or springy floorboards. A shelf, mantlepiece, bracket or heavy unit on a concrete floor are infinitely better. They should be level but if the place is slightly out of true, the clock may be adapted to suit, as explained below. If you are thinking of setting up a 400-day clock in the foothills of the Himalayas, don't bother! Get a carriage clock instead. The frequent earth tremors in this region are enough to disturb the delicate balance of a 400-day movement and it will repeatedly stop. I expect California is much the same.

Longcase clocks (or Grandfathers) should be positioned on a level floor, preferably without a carpet underneath, and wedged to ensure stability. Once set up, they should be screwed to the wall, particularly if standing on a carpet or where there is any likelihood of movement caused by loose-fitting or creaking floorboards. If they are left free-standing the tendency is for them to stop, usually when the weights and the pendulum are of equal length and oscillate in harmony with each other (often day four for an eight day movement).

Wall clocks require a brick or blockwork wall, not the one with a door or window in it as constant opening and closing will send vibrations through the clock. For the same reason stud partition timber walls are not suitable. It must be level and perfectly vertical or the pendulum may come into contact with the weights or backboard. And don't hang it over a radiator or fireplace where it will be subjected to intense heat and rapid temperature variations. Also avoid any position where it is liable to be knocked as someone passes by. Hang it from a secure screw, preferably a domehead rather than a countersunk as there is less risk of it sliding off. Ensure it is big enough to support the weight and small enough to fit the hole in the back of the clock. Never use a nail. Ensure that the screw is driven almost fully home to hold the clock close to the wall. Don't try offering the clock up and then screwing it in place; instead, hang it like a painting.

 

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FITTING THE PENDULUM: Never move a clock with the pendulum attached.

Fitting the pendulum after placing the clock in position is essential to avert the risk of physical damage to the case or glass as the pendulum slams into it while in motion. Moving it with the pendulum attached also places unecessary strain on the delicate steel suspension from which it hangs and risks expensive damage to the escapement. Further, it could easily knock the clock 'out of beat' - see below.

Hanging the pendulum is simple but do make sure that the top seats correctly on the bottom lugs of the brass-tipped steel suspension and that the rod properly engages with the crutch. The crutch is the vertical arm at the back of the clock with a fork or loop at the bottom which engages with the pendulum. Driven by the clock, it delivers the impulse that powers the swing of the pendulum. 400-day clocks are an exception to this design - a fork fitted near to the top of the suspension engages with an anchor pin instead

Once the pendulum is attached, it is well worth a very gentle two-fingered tug downwards to make certain that the suspension is straight. Finally, ensure that the pendulum can swing freely and that the bob is straight.

Wall clocks can be slightly different. In a spring-driven 'Vienna' the pendulum hangs from a brass extension of the suspension. You'll see it hanging just below the movement at the back. In a weight-driven Vienna, the pendulum and suspension hang from the case itself, not from the movement. So you will have to fit the pendulum onto the suspension first. When you then fit the movement, be sure that the arm of the crutch engages in the cutout in the pendulum. Again, a very light tug downwards will help avoid any misalignment and, if the Vienna is a striker, check there is no snagging of the coil gong. Also, do check carefully that the bob swings squarely and that there is a gap between it and the backboard; if the clock is not exactly vertical there is a risk that the rear of the pendulum will brush it and any contact will eventually stop the pendulum.

 

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WINDING: Don't be afraid to wind the clock fully.

Contary to popular belief it is extremely hard to over-wind a spring-driven clock and you'd have to be pretty determined to try. The likelihood is that you'd bend or break the key before you break the spring.

Invariably, I let down the springs completely before shipping for reasons of safety so when you first wind the clock, it will take more turns of the key than usual to run for a week. The number of turns can vary from one type of clock to another; American clocks take more turns that French and German ones. If the clock won't run for its due period, you're probably not winding it up fully. So simply wind it until you feel the spring come to a definite stop.

It is important that it be fully wound once a week (or every day in the case of a 30 hour movement) because of the timekeeping issues mentioned below. So get into the habit of winding it the same day each week. Weight-driven clocks are different; they exert a consistent force (which is one reason that they are often more accurate day by day). Wind the weights up to the point just before the hooks are about to come into contact with the movement. They should hang freely and vertically.

If the clock strikes and chimes, don't forget to wind up those trains, too. But please don't bother trying to set the time yet. There's more to be done first.

 

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CHECK IT'S IN BEAT: Listen carefully to it tick/tock.

In beat is the term given to a clock when the intervals between the 'ticks' and the 'tocks' are equally spaced.  A clock is termed 'out of beat' if, when placed on a straight and level surface,

  • the tick/tock is uneven
  • it won't go at all or
  • it will go but only if the clock is raised on one side.

Gently set the pendulum swinging.  After a minute or two, when it has settled down, check the sound of the ticking. You should hear a consistent: .... tick .... tock .... tick .... tock .... tick .... tock .... tick .... tock. Think: metronone, or dripping tap!

If it sounds like it's 'galloping' ( ....... tick-tock ....... tick-tock ....... tick-tock ....... tick-tock .......), it's out of beat. A clock that is out of beat is likely to stop because the pendulum is not receiving the optimum impusles to keep it swinging. If it's badly out of beat it will stop within a few minutes. If it's only slightly out of beat it could run for days but will eventually stop earlier than it should. But don't worry, it's not terminal and can be cured:

Carriage clocks and other clocks fitted with a balance wheel and hairspring are too complex for the inexperienced so leave them alone and get professional help. Trust me, if you fiddle with them and don't know what you're doing, it'll all end in tears and a bigger repair bill.

For mantle clocks with a pendulum, a temporary cure may be to place something under one side of the clock, such as a coin, and listen again to see if it's any better. If it's worse, place the coin under the other side instead and listen again. Add two or three coins if you need to untill the tick sounds even.

But for a permanent cure, you will need to adjust the crutch as follows (you cannot do this with a 400-day clock and there are other, simpler, ways to deal with French mantle clocks and most wall clocks - see more below for these types):

Putting in beat by adjusting the crutch

The aim is to adjust the angle of the crutch without disturbing the position of the escapement to which it is attached (the steel bit at the top that stops the brass escape wheel turning). Most wall clocks and many French clocks can be put in beat easily if they are not too far out. For the rest, a combination of good hearing, a quiet room and perseverance is required to adjust the crutch.

You won't need any tools but before you begin, you need to determine which side you need to move the crutch. First, stop the clock by holding the pendulum in the central position. Then carefully move it first to the right, until it ticks. (If it doesn't tick, move it to the left, instead). Then do the same on the opposite side. Determine which side requires the least degree of movement from the vertical position.  It is in this direction that the crutch needs to be eased. You can repeat the process as often as you need to until you are sure.

Many movements have a simple friction joint, which allows the crutch to be adjusted on its shaft (arbor) without bending. To adjust these, move the crutch in the desired direction to the limit of its free travel and then apply slight pressure. If the movement is fitted with a friction joint the crutch will turn slightly on the arbor. It only needs to move the tiniest fraction; you can always adjust it again after you have retested the pendulum swing. If the swing of the crutch is restricted (say, by pins protruding from the back-plate), the escapement will have to be held at the top with one hand while the crutch is repositioned. If the crutch starts to flex, let go at once.

Where no friction joint is fitted, the crutch arm may need to be bent; this may sound a little drastic but it is the recognised (and only) method and very common on longcase clocks. But be gentle, and never put any firm pressure on a crutch against the escapement as this may snap the pivot or cause other serious damage. Instead, bend the crutch against the resistance of the other hand or between fingers of the same hand. Only make a very small adjustment before re-testing. As it is not possible to measure the alterations you are making, it is largely a matter of trial and error and several attempts may be necessary.

Wall clocks may be given final adjustment simply by moving the bottom of the case very slightly to one side or the other until they can be heard to be in beat. A small misalignment should not be apparent from across the room but if it hangs out of true vertical by more than that, then you'll need to adjust the crutch as above. Some fine movements (weight-driven Vienna regulators, for example) have adjustable crutches, allowing for very precise alterations. You'll need to stop the pendulum each time, to turn the knurled screw with your fingers until you get it in beat.

Antique French clocks will often have metal straps holding the movement in the case. By slackening the two screws on the back door and rotating the whole movement from the front bezel one or two degrees to the left or right, it may be possible to put it in beat. But if this puts the dial visibly out of true vertical, you'll have to adjust the crutch as above. Don't forget to re-tighten the screws to prevent the clock from rotating when being wound.

400-day clocks have an unjustified reputation for being temperamental. But as they unwind nearly fifty times slower than a French mantel clock, there are much more sensitive to error so be particularly careful. If the clock is supplied by me you can be reassured that it is already set up properly. If it was not supplied by me, and you really want to try it yourself, there are plenty of useful websites explaining the process but here's my approach. Stand with your head over the top of the clock an watch the escape wheel click one tooth as the pendulum nears the end of its rotation in one direction. As soon as the tooth is released, measure (in your mind) the 'overswing' of the rotating pendulum - how much further it continues to rotate. Then watch the pendulum rotate the other way and compare the overswing when the next tooth is released (8 seconds later). It is important that the overswing at both sides is the same or else the clock will probably stop after a few minutes. If it is not, there are various methods of adjustment but the commonest is a screw at the top which needs to be turned the tiniest amount in the direction of the least overswing. It sounds worse than it is but should only be attempted if the clock does not run at all, as then you cannot make it much worse!

 

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REGULATING: For accurate timekeeping.

The quality of the movement will have a major influence on a clock's ability to keep good time. But construction material, temperature, the earth's rotation, height above sea-level and even the day of the week can also affect its performance. The longer the pendulum, the slower the clock will tick so high temperatures in Summer can slow a clock down through the effects of expansion on simple steel pendulum rods. Wooden and bi-metallic rods and mercury-filled pendulums compensate for this. The gyroscopic effects of the earth's rotation can also affect the truth of the swing of the pendulum. And if wound at weekends, most spring-driven 8-day clocks (fusees excepted) will run faster on Mondays than on Friday because the mainspring delivers more power when fully wound. Weight-driven clocks are not susceptible to that problem. 400-day clocks have a reputation for poor time-keeping but again it is unjustified. It's just that most clock hands are only reset whilst the owner is rewinding the clock: ten seconds a day means an adjustment of just one minute at each rewind for a French 8-day clock, which sounds very good. But this could mean half an hour or more at each rewind for a 400-day clock. Furthermore, temperature has little effect on a 400-day clock because of the development of modern alloys (Ni-Span C) that compensate by stiffening more as the temperature rises.

No matter how well a clock movement has been overhauled, some final adjustment is almost always necessary. But before making any adjustments, give the clock time to settle down - a fortnight at the very least.

After that, a clock can be regulated by fractionally raising or lowering of the bob weight on the bottom of the pendulum. Raising it will shorten the swing and so make the clock run faster. Lowering it has the opposite effect. Most pendulums have a rating nut under (or in ) the bob and adjustments should be small and infrequent. Because of the way the power reduces as the spring unwinds, there is no point in making adjustments every day or the adjustments you make on Monday to slow the clock down will have to be unmade on Friday to speed it up again. An eight-day movement might well run for 12 or 14 days before it finally stops but timekeeping after a week tends to fall off drastically so there is no point at all in adjusting the pendulum on a clock after eight days. Ideally, you're looking for a compromise across the whole week.

On French clocks with a Brocot suspension, it is possible to alter the swing of the pendulum with a small watch key by turning the arbor that is just visible in a tiny hole above the Twelve on the dial. Turning it clockwise direction shortens the effective length of the pendulum, thus making the clock run faster.

Again, 400-day clocks are different. Those with four balls (sometimes three) have a knurled nut in the centre of the top of the pendulum usually marked with arrows and S and F (for Slower and Faster) stamped on it. Follow the arrows but generally you will rotate the nut anti-clockwise to make it run faster and clockwise to slow it. Earlier models have flat discs that need a small square-end key to draw the two small weights inwards towards the middle (to make it run faster) or outwards towards the edge of the disk (to make it run slower). Only the tiniest adjustment is required - just a few degrees. If it gains or loses half an hour a day, you probably have the wrong suspension fitted so see the person you bought it from (it won't be me).

 

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SYNCHRONISING THE STRIKE: Never wind the hands backwards.

When a clock winds down (as it will before shipping), the strike train may stop before the going train and the strike therefore gets out of sync. i.e. it strikes the wrong hour or the half hour on the hour. Transit movement by road can have the same effect as an almost completely run down spring can still turn a strike wheel when it's placed on its side.

To correct this, you can slowly move the minute hand FORWARD with one finger (for a carriage clock you can do from the back with the other end of the winding key). As you approach the 6 or 12 slow down to allow the strike train to engage. You will hear a 'warning' just before it is due to go (a short whirring sound that quickly stops). As the minute hand crosses the 12 there will be a click and the strike will activate. If you hear only one, continue moving the minute hand forwards and repeat until you hear more than one. If the minute hand is on the 6 when this happens keep turning it while the strike is running until the hand is just past the 12. Then turn it round to the 6 again and the half strike wil run (1 strike of the gong). Finally, move the minute hand just past the 12 and count the number of strikes. Then move the hour hand to correspond with the number of strikes. It is only a friction fit on the arbor so it will turn quite easily.

If you miss, try again until you succeed.

Spring-driven Vienna regulators are easier to synchronise: look just for a lever with a hole in it; you'll usually find it between the 1 and the 2 behind the dial but is can be located on the opposite side (behind the 10 and 11). Pressing it will advance the strike by half an hour at a time. Every time you press it the strike will advance by another half-hour so you can repeat the process, allowing it to strike each time, until it is correct. There is a similar lever on weight-driven Viennas, too, but it acts like a repeat - repeating the last hour - and will not advance the strike train.

One manufacturer of 400-day clocks (Kaiser) recommends never turning the hands forwards to set the time: they say it risks damaging the small wheels under the dial (the 'motion work'). Kaiser recommends that you only turn the hands backwards. I can understand the science behind this but I've not heard of any other clockmaker suggesting it so be warned. The fact is that in a clock that does not strike or chime ('a timepiece'), you can probably wind it backwards without causing damage but it's better to get into the habit of winding clocks forward so that you don't make a mistake. When you need to turn the clock back an hour (to BST) in the Autumn, if it has a pendulum try just stopping it for an hour and then restarting it again.

 

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SYNCHRONISING THE CHIME: For three-train clocks only.

A three-train clock (one with three key holes) will sound the four quarters on chimes (usually Whittington or, more commonly, Westminster (Big Ben). Transit can lead to these getting out of sync too. But fortunately they are self-correcting, providing you wait two hours while they go through the full cycle.

If the clock is not chiming or striking at all, leave it to run for two hours and on the second hour the chimes should start to work.

 

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