Title Practical Watchmaking 12.9 MB 176
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Vigniaux

Practical
Watchmaking

Translated By
Richard Watkins

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Vigniaux Practical Watchmaking

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not spring. It would be prone to break and it would often slip on the verge, and would
necessarily cause variations and often stoppages.

The Number of Vibrations per Hour which a Balance without a Balance Spring
must give.

339. Let us suppose the movement is finished, and all the parts are in the frame except
for the balance spring. In this state the vibrations of the balance will be slow. So that its
weight is related to the action of the mainspring, the various frictions, and the other
consequences to which it is prone while running, it is necessary that the balance without the
balance spring makes the minute hand describe only twenty-seven or twenty-eight minutes
per hour. If it does not describe this number, it is necessary to decrease the weight of the
balance in proportion to the slowness of its vibrations. This is done by decreasing the
thickness or the width of the rim of the balance. For that one files a bevel on the part B, Pl.
10, Fig. 4; this method does not harm the shape of the balance. One can arrive at the same
goal by decreasing the width of the rim of balance. It is desirable that all its weight is on its
circumference; but as one can only do it by losing much space, because of the greater
thickness which one would give to balance, it is to better stick to the ordinary design.

If, on the contrary, the minute hand describes more than twenty-eight minutes per hour,
it is proof that the balance is too light. Make another rather heavy, so that it gives only
twenty-seven to twenty-eight in the same space of time. Experience proves that this number
of vibrations of the balance per hour is the best for the various frictions, movements and
accidents to which a watch is exposed. So follow this rule if you want a well adjusted watch.

Observations on Oil and the Oil Sinks of the Escapement.
340. Never put oil on the teeth of verge escape wheels, or on the pallets of the verge. If

you find some there, carefully remove it, because any that remains would cause variations.
However, take care to put one drop of oil on the pivots of the verge, and those of the

verge escape wheel, to prevent them rusting in their holes, and so that they do not corrode
the brass quickly, or they themselves are corroded by it. Besides, this oil will give freedom to
the escapement. But as it sometimes runs onto the pivot shank of the verge, someone
thought of forming two types of lenses, one on the heel of the potence and the other on the
coqueret. Form them in a bevel; file the circumference until you have removed almost all the
thickness from it, and continue to form the bevel to the hole. By this means you will give the
head of the brass coqueret the shape of a lens. This shape is given to it so that, when a drop
of oil is put in the hole for the balance and the steel coqueret is put on the brass one, the drop
of oil between the two coquerets is attracted by one and the other. The oil will be held there
as if it were in a tank, and will maintain the pivot. By taking the same precaution for the heel
of the potence, you will have no fear of the oil seeping onto the pallets of the verge. As for the
nose of the potence, the only way one can prevent the oil being communicated to the pinion
or the verge escape wheel, is to make a small recess in the pivot hole to contain the oil.

Method of making Oil Sinks for all the Pivots of a Watch.
341. Oil is almost as necessary to the pivots of the other wheels, as with those of the

verge escape wheel and balance. To make the oil sinks to contain it, use a drill with a round
head for recessing the holes. Make the recesses deep enough for the ends of the pivots to
protrude a little above the hole in the plate. Without that the pivots, by corroding the walls of
the hole over time, would form a type of cavity under the plate, which, engaging or
obstructing the pivots, would stop or vary the watch. Thus with each hole make a small oil
sink which can hold one drop of oil, which, held in the thickness of plate, will not be likely to
be communicated to the pinions and will keep the pivots safe from rust. You could also use
the set of cutters, Pl. 11, Fig. 4.61

The oil which one puts on the pivots must be of the first quality. Many workers prefer
that which is purified with lead, or which is clarified simply by filtering it through grey paper.

61 This plate reference is wrong; it probably should be Pl. 1, Fig. 4.

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Chapter XI: The Variations of Watches.
No. 342. It takes much time to regulate watches. It is from the many experiences and the

skills of the best artists that we owe the exactness of these machines. If you reflect on the
causes of their variations, you will be surprised that one can eventually regulate them as well
as it is done.

I would never finish, if I wanted to go into the details of all the causes which contribute to
making watches vary. I will speak only about those which are most common, and which are
most easily observed. These are:

1. The elasticity of the mainspring;
2. The friction of the train and the pivots;
3. The thickening of the oil;
4. The changes of the seasons;
5. The various positions of the watch which affect the movement of the balance;
6. The action of the balance spring.
1. The action of the mainspring especially influences the regularity of a watch. It is very

difficult to make its blade of equal thickness, to harden it and temper it so that its elasticity is
the same throughout its length, and to equalize it to the fusee, so that the fusee compensates
for all the inequalities of the spring on all the steps on its spiral circumference.

2. No matter how much care a skilful worker takes, he will never make teeth perfectly
identical. At the same time the pinions are made with the greatest care, but they always have
roughness which, although not visible, prevents the train being uniform. The pivots have
larger or smaller shoulders, and they are more or less round, more or less polished. Unite
with these the difficulty which one has giving, by means of the gearing, perfect agreement of
one part to the other.

3. One needs oil to prevent the pivots rusting, and to prevent them rapidly corroding their
holes. Oils are more or less thick, according to how much the pivots form dirty oil in their
holes.

4. Nobody can ignore the variations of the seasons which make springs more or less
elastic and oil alternately fluid or thick, according to the degree of cold or heat. The first gives
freedom to the train, and the latter impedes.

5. If you reflect on the various situations of a watch, such as resting, moving, shocks,
blows, and the other effects to which it is exposed, you will not be surprised that the
vibrations of balance are sometimes slow, sometimes fast, and so the machine is prone to
vary.

6. The balance spring is about three or four inches long, and about the thickness of a
hair, and it presents to the air a very large number of the parts of which it is composed. This
element influences the spring which, intended to regulate the watch, communicates the
various effects of it, to which it is prone by its nature.

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