This may, in some respects, be called the most tedious of any work connected with watch repairing; for it is certainly no easy job for the novice to drill down the centre of a small pinion, especially when the pinion is left extra hard, which is often the case. Making the drill to the required shape and hardness is one of the main things to be considered. A needle is the best steel to be obtained for this job. Heat the needle in the flame of a candle to a cherry-red, then hammer it into shape. This must be such a form as will give as much strength as possible; therefore, do not hammer the sides too flat, or the edges will snap off when hard. It must not be too pointed for drilling steel, but will work very well without a point, provided a nice cutting shape is obtained, which is secured by making the end a little larger than the other part, and slightly flattened with the round-faced hammer, then stoning up so that there is an edge in the centre of the flattened part. If this edge is slightly rounded instead of pointed like a brass drill, it will make the drill cut longer than the pointed shape, as there is more of the cutting surface utilised at one time; therefore there is not the amount of wear on any particular point of action, so it will cut long after a pointed drill has become dulled.
To get the drill extra hard, hold it in the candle flame until it becomes a cherry-red, then immerse in quicksilver. Do not get it to a white heat, or the steel will be too brittle, and never cut satisfactorily. A candle is much better than gas for making up drills, as the gas burns the steel, owing to the sharp current of air through the burner. Some use water and some oil to harden the drills, while others use the tallow of the candle. Either will have the desired effect, providing the steel has not been heated too much before putting in - a deep red is quite sufficient.
Suppose the drill is hard enough to cut down the required steel where the pivot is wanted - say a verge third-wheel bottom pivot. After finding the centre, apply plenty of oil to the drill, then drill down until you get about the depth of a pivot's length. Now file the steel a perfect fit to this hole. There is no better steel for the pivot than a needle, brought down to a plum colour. When it is stoned to fit the hole tightly, drive it in with the flat hammer. If it is a good fit, you may now cut it off a little longer than required, run a point on it, put the point into the turns, and see if the pinion runs true; If so, the pivot may soon be finished; but provided you have got the pivot a little out of the centre, you must make the point a little out of the centre of it, so that the pinion will run true; then turn it true before you begin with the pivoting file, or you will find the pivot will never find the centre by filing. Great care should be taken in getting the point of the pivot in the proper place before beginning to turn. With care, pivots may be put in so that the watch will not suffer therefrom. Even if it is a wheel, whose being out of poise does not matter, it will throw the depths unequal, providing the pivot is out of the centre.
It is sometimes rather tedious to get the pinion true from the point of pivot as advised, but there had better be a few minutes taken there than to slip the job and then have a bad depth to correct.
In putting in a verge fourth pivot, if it be a seconds pivot, drill the pinion far enough, or, as before, the length of the seconds pivot - this will make a firm job of it. Care must be taken not to break the drill in; but with a properly shaped drill and a steady hand there is not often a break.
Whether verge, lever, or Geneva pivots, they can all be done in the way stated, but of course a Geneva escape-wheel pivot requires more practice than a third-wheel pivot of a verge watch. With this the wheel must be taken off in order to get the ferule on to run it with. In putting on the wheel again the best tool to use is a pinion riveting tool, as it is then left nice and flat. No-watchmaker should be without this tool, as it is so useful for all kinds of riveting where accuracy is required. It will leave the brass perfectly polished where-it is used to rivet a balance on.
There are pivots where the drill is not used. Some drill in the turns, others-use the mandril, with the wheel shellacked firmly in it, holding the drill on the rest; while others employ the old-fashioned method of holding the wheel in the hand and running the drill in the vice holes. The operator may choose his own method.
Now for a pivot without any drilling - a staff top pivot for instance. Drive out the old staff entirely (the steel part of it), then cut off the steel about half as much as reaches through the brass; stone the end flat, then put it in again as before. This will leave a hole in the top part. Put a piece of properly tempered steel in this hole, solder it in with a small portion of solder, then centre the point so that the body of the staff runs perfectly true; put it in the turns, and turn down to required shape for pivot, finishing off with file and burnisher. This is the best method for a staff top pivot, which can be done without much fatigue. Of course this method cannot be resorted to when it is a solid steel staff, such as the Waltham staffs. In this case the drill has to be used; but when the operator has had plenty of practice with the turns he would be very likely to put in a new staff rather than a pivot. Even in putting in a new staff (English), the steel can be driven out, and another piece put in, saving the trouble of turning the brass.
In doing this, care must be taken to get the old brass to run true on the centres before using the graver, or the balance will be out of poise.
We now come to the easiest pivot job, although by some it is thought to be a very delicate and tedious job - the cylinder pivot. Provided the top plug is a good fit, but has the pivot broken, simply drive out the plug a little way (the length of the pivot) and run a new pivot on the same plug; turn it back a little way to give it a good appearance. This may be done complete in 10 minutes; so it is not very serious after a little practice has been had at it. In driving out the plugs, make a steel stake with holes through and chamfered on the top; this will let the plug move while the shell is held firmly on the stake.