To take the movement to pieces, begin by detaching the hands with a pair of nippers (if it is carefully done, the hands will not be marked), then draw out the pins which hold the dial, and remove it. These pins are sometimes very troublesome to get out with the nippers or pliers, and are often best removed by pressing the edge of a knife into them close to the dial feet, and using the blade as a lever. The mainspring must now be "let down." Unscrew the click screw a little, place a fitting watch-key upon the barrel-arbor square, relieve the ratchet, and gradually let the spring down. Beginners should always make it a rule to let down the mainspring at the commencement, and if the watch has maintaining power, as most lever watches have, also to relieve the detent, for it is a very bad plan to let the train "run" down, and if by any chance the top plate is removed with the spring wound up, the effect would be probably most disastrous. The motion work, including the cannon pinion, being removed and the spring let down, proceed to unturn the cock screw, and take off the cock. The cock is the piece that receives the top pivot of the verge, staff, or cylinder. See that none of the screws overturn; it is important that all screws should be perfect in this respect.
Withdraw the pin that secures the balance spring to the stud, turn round the balance until the spring is free of the stud, and remove the balance. In some watches, the curb pins will be found bent over to prevent the balance spring from escaping from between, or more than one coil getting in. In such cases, the balance spring must be freed from the curb pins as well as the stud before attempting to remove the balance. Proceed to take off the name-plate and regulator slide, push out the pillar pins, and remove the top plate, when the wheels may be removed from their positions, and the watch will then be "taken to pieces."
Clean the various parts before proceeding with the examination. Before beginning to brush, the oil and dirt must be wiped off the plates with a small piece of clean chamois leather. The wheels and pinions must be well brushed, and the leaves of the pinions thoroughly cleaned with a pointed piece of pegwood. A small piece of elder pith will be best adapted for cleaning the pivots.
When the dirt and oil are removed from every piece, and the pivot holes in the plates have been "pegged out" until the pegwood comes out quite clean, the movement is ready for further examination. See that the pillars are all tight in the frame, likewise the studs that secure the "brass-edge" to the frame when the dial is not pinned on direct. If either of the pillars is loose, pin on the top plate with 4 examining pins; then rest the end of the pillar to be tightened upon a fling block, and carefully rivet the pillar till it is quite firm. In a similar manner, the brass-edge pillars or studs may be tightened, removing the dial and pinning on the brass-edge to the pillar plate. If either of the pin holes is brokenout, or the end of the pillar is broken off, it may be repaired in 2 ways. File off the broken end of the pillar till a little lower than the surface of the top plate, make a centre mark, and drill a deep hole with the largest drill it will safely bear; then solder in a piece of brass wire to form a new pillar end, in which the pin hole may be drilled.
The other way is to use a smaller drill, and fit a screw in.
Proceed to try if all the wheels are tight on their pinions. Hold the pinion firmly between the smooth jaws of an old pair of pliers (or preferably a brass or copper lined pair), and see that the wheel has no movement either backwards an forwards, or up and down. If a wheel is found to be loose, it must be secured at once. Place the arbor in one of the holes of a pinion stake, so that the pinion head rests firmly upon it, and, with a half-round punch and hammer, carefully rivet the pinion until the wheel is tight and runs true in flt.
Such wheels as are mounted upon brass collets, like the contrate wheel in the verge movement, and the escape wheel in the lever, require to be treated rather differently. The collet must rest firmly upon the jaws of a "pair of clams," the clams being held in the vice; then the brass rivet is slightly burred over. In the case of a lever escape-wheel, great care must be exercised, or the wheel will be found out of flat, and it will not admit of being made true by the ordinary method of "bumping." The best method of making it secure is to carefully fix the pinion arbor in the clams, and then use the sharp point of a needle as a punch, making 2 or 3 burrs on the rivet of the collet. By this means, the wheel is rarely thrown out of flat. Ordinary flat wheels are riveted as nearly true in flat as possible, and then, if necessary, "bumped" - that is, the wheel is set up between the ends of a pair of callipers, and by means of a little strip of brass - called a "toucher" - the crossings are found, which require bending to make the wheel run flat. It is then laid across the end of a bum ping-up stake, and the necessary crossings are gently tapped with the hammer until the wheel runs true.
The wheels must further be examined to see if any of the crossings are broken, or any of the teeth broken off or bent. If either of the crossings is broken, there is no good remedy but a new wheel; although sometimes, when the watch is an inferior article or old the crossing may be neatly soldered.
In a good watch, such a thing should not be countenanced. If a tooth is bent, it may frequently be raised to its proper position by the blade of a penknife, and sometimes by means of the tweezers.
To replace a broken tooth, a new tooth can be put in; it is never advisable to put in more than one tooth at the same part of the wheel. A wheel having 3 or 4 teeth broken off consecutively should be discarded as quite unfit for service, and replaced by a new one. If any of the pivots shows signs of wear, is rusty, or in any way rough or uneven, it roust be carefully burnished till quite smooth and straight, and the ends properly rounded up. When all these points are attended to, put the centre wheel in its place in the frame, • pin on the top plate with the examining pins, and see if the centre wheel runs flt with the pillar plate, or, in other words, that the pinion is upright. If it is not upright, rest the edge of the pillar plate on the workboard, and hold a small filing block upon the edge of the top plate in such a position that a few smart taps with the hammer will put the frame in its proper position. This being done, the depths, end-shakes, and pivot holes claim attention. First, try the great-wheel depth with the centre pinion, observing particularly at the same time that the fusee stands quite upright in the frame, for if it leans at all towards the barrel, most likely the chain will not run on properly, but slip up the fusee.