Commence by screwing on the hammer spring and the cock. The cock is put on in order to allow the pivots to go through the holes until the shoulders rest on the plates, as the wheels do not fall about so much then as they otherwise would, and also to prevent the back plate being scratched by the workboard. Place the lower part of the plate towards you, and put the wheels, etc, in their proper places in the following order: - Centre wheel, third wheel, two great wheels, hammer, pin wheel, escape wheel, gathering-pallet wheel, warning wheel, and last, the fly. Take care to have the catgut lines running the proper side of the legs or pillars. If there is an arbor for a " strike or silent " arrangement, put it in now. When these parts are in their proper positions, carefully put on the top plate, and, pressing it moderately tight, guide the pivots into their respective holes, starting from the lower part of the frame. It is sometimes a great assistance to put the point of an examining pin into the holes of the lower pillars, when the top plate is on sufficiently far, as you have only then to attend to the top part.
For the clock to look well when finished, there must be no finger marks upon any part; to avoid which, hold the plates, etc, with a clean duster when putting together, and keep it as bright as possible. When each pivot is in its place, and the top plate is resting fairly on the shoulders of the pillars, pin up with the examining pins, and test the correctness of the relative positions of the wheels. -
There cannot, very well, be any mistake with the "going" train, but it is advisable just to press round the great wheel a turn or so, and see that all runs freely. The wheels of the striking train, however, require to be placed in certain arbitrary positions in regard to each other, except the great wheel and fly, which are exempt. The first position to be tested is that existing between the pin wheel and the gathering-pallet pinion. In order to do this, put on temporarily the rack, rack spring, hook, and gathering pallet. Let the rack hook hold the rack gathered up, with the exception of one tooth, and move round the pin wheel very slowly until the hammer tail just drops off; at that instant the tail of the gathering pallet should have about 1/4 in. from the pin in the rack which stops the striking. If there is an excess of this, or if the hammer tail is resting on a pin, the top plate must be slightly raised, and the pin wheel moved a tooth farther on in the pinion until it is as near this condition as possible. The reason for making the striking chain cease running, as soon as can safely be done after the hammer falls, is that there may be as much run as possible before it has to raise the hammer and overcome the tension of the hammer spring.
Under -no circumstances leave the hammer tail "on the rise" - that is, resting on one of the pins of the pin wheel - when finished striking.
Having adjusted this, see that the run" of the warning wheel is right. Put on the lifter, and gradually raise it till the rack hook liberates the train, and "warns." The distance the warning pin should run is half a turn, so that immediately before it " warns " it should be exactly opposite the piece on the detent, against which it is stopped, until the lifter falls and the clock strikes. See that the warning pin catches fairly on the stop-piece of the detent; if it does not, it is because the rack hook is raised either too soon or too late by the detent: alter as may be necessary. When the train is quite correct, remove the rack, etc, and pin up the plates finally with good-shaped pins.
It matters little what care may be bestowed upon repairing and cleaning if the clock is badly pinned up, for no certainty of performance can be expected in such a case. Therefore make a proper shaped pin, not too thorny nor too straight, but gradually tapering, round and smooth, and well fitting the hole it is intended to occupy; then drive it in tight, and cut off at an equal length each side of the hole. The front plate will now be ready for oiling.
To make an "oiler," file up a piece of iron wire something like an examining pin, but about 4 in. long, and then flatten out the end like a drill. A very good oil for house clocks is olive oil. Pour some into some small vessel, and with the point of the oiler proceed to oil the pivots of the front plate by putting a little into each sink. A very little is sufficient, or it will flow over, and run down the plates, giving a very bad appearance. Slightly oil the studs upon which the rack and other parts work. The cannon-pinion spring may now be put on the centre arbor, and the cannon pinion and minute wheel in their places. They must work together in such a manner that the lifter falls exactly when the minute hand is upright; put the minute hand on the square of the cannon pinion, and see that it does so, or move the cannon pinion a few teeth in the minute wheel until right. The remainder of the dial work may now be put on, and the only items to observe are that the hour wheel works into the minute-wheel pinion, so that the hour hand is in its proper position when the clock strikes, and that the proportions and fall of the rack are correct.
These are very important matters, and must be left exactly right, or the clock will be continually striking wrong.
Few clock repairers understand the proportion which should exist between the rack and rack tail. Fig. 217 will probably make the matter quite plain. To test the rack in its place, allow it to fall until the tail rests on the lowest step of the snail; the rack hook should then hold the rack, so that there are 12 teeth to be gathered up; then try it on the highest step - it should now exactly fit in the first rack tooth, leaving only that one to be gathered up. Supposing the clock strikes 13 when on the lowest step and 2 when on the highest, it shows that the end of the rack tail is a little too far off from the snail, and must accordingly be set a little closer. If, however, it strikes the right number when on the lowest step, and 2 when on the highest, then the proportion between the rack and rack tail is wrong; the rack tail travel being too great for the rack. To make the matter plain, suppose that we have to make a new rack tail, which is often necessary in badly used clocks. Measure first with a pair of spring dividers the proper distance that the rack teeth fall for 12 to be struck by the clock, and mark that distance on a piece of paper, as shown 6 to a; then take the distance from the points of the rack teeth to the centre of the stud, upon which the rack works, and mark that as shown 6 to c; then from a draw a straight line to c.
Take the total distance the rack tail has to fall - viz. from the top step of the snail to the lowest, and from where the 2 lines, a c and 6 c, are that distance apart, to the point, c, is the length required for the new rack tail. In the diagram, the distance from the highest to the lowest step of the snail is supposed to be from e to d, therefore the length of the rack tail would be from d to c. When all is set right, pin on the dial, and put on the hands. There should be sufficient tension in the spring for the hands to move tolerably tight, or they will stop when the minute wheel has to raise the lifter. It is always best to use a steel pin to hold the hands on.
The clock is now turned over, and the pallets are put in. It is necessary to put a very little oil on the pallets where they touch the escape-wheel teeth, the pins of pin wheel, acting portions of the hammer spring, and crutch. See that the hammer acts properly on the bell; screw on the seat-board, and oil the pulleys.
Finally, put up the clock in the case. Fix the case as firm as circumstances will admit, then see that the seat-board has a good bearing, that the dial is upright and does not lean either backward or forward, and that the crutch is free of the back of the case. Hang on the weights, and wind them up carefully, observing that the lines run properly on the barrels. It sometimes happens that the line is longer than sufficient to fill the barrel, and, instead of forming a second layer across the barrel, rises perpendicularly, until it interferes with the clickwork. The best way to rectify this error is to put a piece of wire across the hole in the seat-board in such a manner as to throw it off as desired. Put on the pendulum, and set the clock "in beat." The meaning of "in beat" is, that the escape takes place at equal distances each side of the pendulum's centre of gravity. When the pendulum is at rest, it should require to be moved as much to the right before you hear the "tick" as it does to the left, and vice versa. When "in beat" it sounds regular, and nearly equal, the differences of drop making it slightly uneven.
The general rule for setting in beat is this: - If the right-hand beat of the pendulum comes too quick, the bottom of the crutch requires bending to the right; if the left-hand beat comes too quick, then the crutch must be bent towards the left. The clock may now be considered finished. Regulation is effected by raising the pendulum bob to make the clock go faster, and lowering it to make it go slower.