The pivot can now be turned down to size, polished, burnished, and the end rounded up. There are several tools sold for centring arbors for drilling, but there is no more accurate way than that described; as, if the hole should get out of truth in drilling, subsequent returning of the centre on the pivot end after it is inserted, corrects this. Should the pallet-wheel front pivot require repairing, a centre will have to be cut with the graver in the end of the square (as usually it is finished off almost flat at the end); then a male centre can be used, and the pivot turned and polished in the usual manner. This pivot is nearly always the first to show signs of wear, owing to the great strain on its locking, particularly in weight clocks.
In many old clocks, particularly in long-case striking clocks, the rack and gathering pallet are frequently found in very bad condition; the pallet perhaps fitting the square very badly, thus making its depth with the rack very uncertain. To make a new pallet is anything but a difficult matter; yet one seldom sees one properly made by the clock jobber. Frequently pallets are made of brass, a most unsuitable material for this purpose for English clocks, where the pallet not only has to gather up the rack, but also to stop the train at the conclusion of the striking. If the rack depth is planted as deep as it ought to be, there is not room for a very stout boss to the pallet, and nothing softer than steel should be used for this purpose in good work. In the absence of a proper forging, a pallet may be made from a square bar of steel.
Thick enough to give the requisite length of boss. Mark the length of the tail of the pallet, and file it down to almost the required thickness; file also the opposite face of the bar smooth and flat. Mark the position of the hole, and drill it at right angles to the face; the diameter of the hole will be the same as the small end of the square on the pallet pinion - measuring across the fiats, of course. Start the corners of the square in the position you require them with a good square file; then take a piece of broken square file of rather a coarse cut, and of the same taper as the square on the pinion; oil it, and drive it in with a few light blows of a hammer, turn the pallet over and knock it out again, turning it a quarter round each time you withdraw it. In a few minutes you can thus form a good square straight hole, and fit it accurately to pinion-square, put it on an arbor, and turn the ends square and to length, see that the tail is at right angles to the hole, also file the boss to form and shape the lip. This is usually made straight and the back sloped off; consequently it scrapes the rack teeth with 1s extreme end only, and wears quickly.
As the pallet is in reality a pinion with only one leaf, its durability is increased by curving the face similar to a pinion leaf cut in half. The end of the tail of the pallet should be rounded and finished off smoothly at right angles to its face, its length such that it is well free of the pin in the rack when gathering the last tooth but one, and rests fairly on the pin when the rack is up.
If the tail of the pallet were left quite straight, and the end filed off square, there would be danger of the rack being held up by the pallet, particularly when the pin in the rack is planted lower down than it should be, its proper position being rather above the top of the teeth. The tail of the pallet is therefore curved to just throw the rack off.
If any of the rack teeth are damaged at the points, it may be necessary to slightly top all the teeth and file them up again; only the backs, or curved sides of the teeth, should b. filed, finally taking the burr off with the oilstone slip. In order to make the depth correct again, the lack arm is carefully hammered a little, to stretch it; great care must be taken to keep the teeth truly in circle, also to see that they are well five of the boss of gathering pallet - not only when it is in position resting on the rack pin, but also when it has moved into the position that it would be in when the clock has warned. If the boss of the pallet is not perfectly concentric, it may be just foul of the rack teeth in this position, although 'free when tried with the pallet resting on the stop pin. Sometimes this fault occurs in clocks that have been recently repaired, and, unless you suspect it, it is rather liable to escape detection, as workman divide the run differently Apparently, some consider this a matter of no importance, as you sometimes meet with clocks in which the hammer begins to lift as the clock warns, and a lot, of useless run after the hammer has fallen.
This is just the reverse of what should be the case, as the more run you get before the hammer begins to lift, the less probability there will be of the clock failing to strike when the oil gets thick.
A frequent source of trouble in some old clocks is the spring tail to the rack; it is intended to allow the hands to set forward without allowing the clock to strike. If the spring is weak and the rack spring strong, it sometimes gives a little and allows the rack to fall lower than it should, consequently a wrong hour is struck; an excess of end-shake to the hour wheel will also cause this fault, if the snail is mounted on the hour-wheel pipe. This is of course easily corrected by a thicker collet in front of the minute hand.
Another part that in ordinary clocks gets but little attention paid to it is the suspension spring for the pendulum. Any old piece of spring is generally considered good enough to make a suspension spring from, and the consequence is that one seldom meets with a spring that does not wind or twist more or less, it being almost impossible to straighten a curved piece of spring and keep it quite flat. If you wish to have the best material for this purpose, get some straight lengths of steel from the mainspring maker, of various thicknesses, and keep it for that purpose; they cost but little, and save time in grinding down, straightening, etc. The chops at the top of the spring are usually made by cutting a slit in a piece of brass of suitable thickness, and closing the slit down with the hammer upon the spring until it fits it.