A much better plan is to make the chops of 2 pieces of brass, and rivet them together with 4 rivets; the bottom edges should be slightly rounded off to prevent any chance of the spring breaking at that point, as it sometimes does if the edges are left sharp.
With regard to the strength of the spring, very few are met with that are too thin; but many err in the opposite direction, and are very much too thick. It is not always advisable to substitute a much thinner spring - especially should there be but little room for the pendulum to vibrate in, as sometimes the arc is so much increased as to cause the pendulum to strike the sides of the case, rendering it necessary to substitute a lighter weight or a weaker spring. The slit In the top of the pendulum is usually cut with a thin saw, and then closed with the hammer; but there is no certainty of keeping it straight this way, and it takes but little more time to file a true slot and fit a slip of brass to fill it up to the proper size, thus keeping the spring true with the rod.
For making new holes in the plates of clocks, many workmen use a punch which is more fit for a blacksmith, and hammer the plates about to close the holes which are worn. Instead of bruising the plates with such an instrument, why not go the right way to work, thus: cut off a piece of hollow brass wire (after it has been filed true and slightly tapering), open the hole so that the wire can be driven tightly in; if you cut it off the proper length so that it just goes through the plate, it is very little trouble to reknit in, and when the job is done, and properly chamfered, it looks neat, and is in every respect better than a hole which has been knocked out of the round, and often out of depths. With this little matter, the first trouble is the best, for even if the knocking or punching job does answer for a time, it soon gets worn again. This method is preferable for English, French, and American clocks. One way of putting teeth into wheels is to make a hole through the plate of the wheel immediately below the point from which the tooth has been broken. Let its diameter be a little greater than the width of a tooth. Next, with your tooth-saw, cut down where the tooth should stand till you come into the hole.
You then dress out, with a head upon it, a piece of brass wire, till it fits nicely into the cut of the saw, with its head in the hole. With a fine graver you then cut a crease into the wheel plate above and below, on either side of the newly fitted wire; after which, with your hammer, you cautiously spread the face of the wire until it fills the creases, and is securely clinched or riveted into the wheel. This makes a strong job, and one that dresses up to look as well as any other.
The collet in front of the hands is a little thing, but it is seldom right; one that will hold the hands firm, and allow them to be moved small portions of space with ease and certainty. Before making a collet, first straighten the minute spring, and put it on its place on the centre pinion. Put the minute wheel on its place on the top of it, and then the minute hand on its place; now see the space there is from the surface of the hand to the pin hole in the centre pinion. Make the collet so high that it will just cover the hole, and then cut a slit in the collet just as deep as the hole is wide. Make the slit to correspond with the hole in every way, and in such a manner that when the pin is put in it will fit without shake. A collet made in this manner will last as long as the clock, and when the minute spring is set up the hands will always be firm, and at the same time move easily, and not affect the motion of the clock when they are set backward or forward. The square on the pipe of the minute wheel sometimes projects through the minute hand, and the collet presses on it in place of the hand.
When this is the case it should foe filed down, because the minute hand cannot be held firm unless the collet be very much hollowed at the back, which it is not always advisable to do.
The suspension of the pendulum, the pendulum spring, and the action of the crutch, or back fork, on the pendulum, are all of the most vital importance. The spring should be perfectly straight', and should fit into the slit of the cock without shake, and the slit should be perfectly straight, and at right angles to the dial of the clock. The back fork should fit easily and without shake, and the acting part stand at right angles to the frames. The pendulum bob should swing exactly in a plane with the frames and the dial. After a clock has been put in its case, before putting on the head, it is well to get up high enough and look down to see that all these parts work as has been described. Before taking the movement out of the case, it is advisable to see whether you can find out the immediate cause of stopping. The points to which to direct attention are: The hands, to see if they are in any way bound; the catgut lines, to which the weights are attached; the striking parts, to see if there is any mishap connected with them; and the pendulum, to see if it is free. If all these things are correct, and the clock appears dirty, conclude it wants cleaning, or that it needs some repairs which will necessitate its coming to pieces.
Having satisfied yourself on these points, proceed to take off the 2 weights and the pendulum, and remove the movement to your work-board to undergo the requisite examination, cleaning, and repairs. Placing it, dial downwards, on the board, commence by unscrewing the screws by which the movement is fixed to the seat-board, and remove it. The bell-stud screw is now unturned, and the bell, bell-stud, and screw are placed on the board; then the bridge or "cock" screws and the pallets are taken out, and the cock is screwed back in its place. The cock is replaced, so that you may turn the movement over without fear of scratching the back plate, and it is left on till the last thing before the actual cleaning commences. The clock is now turned over face upwards, the small pin that secures the hands is removed with the pliers, and the collet or washer and hands are taken off. Pull out the pins that hold the dial, and remove it.
The movement consists of 2 distinct sets of "trains" of wheels, set within 2 brass plates, which are kept the proper distance apart by turned pillars. These are riveted to the back plate by one end, while the other ends pass through holes in the corners of the top plate, and are there secured by pins. One train of wheels and pinions constitutes the "going" part of the machine, and the other, with the various appurtenances connected with it, the "striking" mechanism.
The going train comprises the first or great-wheel and barrel, upon which the line runs; the centre wheel and pinion; third wheel and pinion, and the escape wheel and pinion. The striking train comprises the striking great-wheel and barrel; pin wheel and pinion; gathering pallet, pinion, and wheel; warning wheel and pinion; and the fly and its pinion. The names of the other parts of the clock are the pallets and crutch; cock; pendulum; bell-stud and bell; motion-work, embracing the cannon pinion, minute wheel, hour wheel, and snail; the hammer and hammer spring; lifter; detent rack; rack spring; rack hook, and gathering pallet.
The parts of a wheel are the teeth, the rim, the crossings, and the collet, or piece of brass on which the wheel is riveted. The parts of a pinion are the leaves or teeth, the arbor or axle, and the pivots which ran in the holes.
Having obtained a good general idea of the mechanism, proceed to take the clock to pieces. Remove the motion-work, and the various parts connected with the striking, which are under the dial; pull out the pins which hold the top plate on, take it off, and remove the wheels. Take off the hammer, tail spring, and the cock, and the clock will be ready for cleaning.