To be of service to this cla.s.s of workmen chapters XI and XII are devoted to preliminary notes and practice lessons.

The contents of these chapters can be worked out in practice by almost any workman who is capable of holding a position as watchmaker and it is substantially necessary that they be mastered before finished results are to be expected.

CHAPTER XI

PRELIMINARY NOTES AND PRACTICE FOR BEGINNERS

44. _Practical Suggestions._

Experience will eventually prove that most of the variations in positions are caused by apparently insignificant details. The mistake made by the average repairer is generally that of failing to detect these details and to make slight corrections where necessary, as he proceeds with the ordinary cleaning and repairing of the watch.

This oversight often prevents what would otherwise be excellent results in timekeeping and makes it necessary to utilize extra time and labor in the effort to obtain more consistent timekeeping.

45. _The First Point of Consideration in Learning to Adjust._

The first consideration in position adjusting should be directed toward equalizing the time in the two horizontal positions. This equalization should be accomplished entirely by attention to details that can be plainly seen before arriving at the point of actual timing of the watch. The princ.i.p.al requirement for equal time between dial up and dial down is equal arc of motion of the balance in each of the two positions, and the adjuster should become capable of obtaining this equal arc of motion before attempting to obtain close rating in the other positions.

46. _Causes of Variation Between Dial Up and Dial Down._

Variations between dial up and dial down may be due to one or more of the following causes which have been arranged in two groups, the first group consisting of the most frequent and common causes, while the second group consists of causes equally detrimental but less common.

Group No. 1

1. Dirt or thick oil in one or both balance jewels.

2. Burred or marred balance pivots.

3. End of one balance pivot flat or rough and opposite pivot polished.

4. Ends of both balance pivots polished but not same form.

5. Balance pivot bent.

6. Hairspring rubbing balance arm or stud.

7. Hairspring concave or convex in form instead of perfectly level.

8. Over coil rubbing under balance c.o.c.k.

9. Over coil rubbing center wheel. (Some watches).

Group No. 2

10. Balance pivots fitted too close in jewels.

11. One pivot having excessive side shake and the opposite close fitting.

12. Escape or pallet pivots bent or damaged.

13. Balance end stone pitted or badly out of flat.

14. Over coil rubbing outside coil, at point where it curves over spring.

15. Balance arm or screw touching pallet bridge.

16. Balance screw out too far, touching bridge or train wheel.

17. Safety roller rubbing dial plate or jewel setting.

18. Fork rubbing impulse roller.

19. Guard pin rubbing edge of safety roller.

20. Roller jewel long and rubs guard pin.

47. _Short Motion Generally Indicates Where to Find Trouble._

Any of the above irregularities will cause a variation in motion between dial up and dial down and invariably the trouble will be found on the side which has the shorter motion. For instance, a pivot that is flat or rough on the end will cause a shorter motion, when it is down, than will the opposite pivot when it is down, provided that its end is slightly rounded and highly polished. The same is true when the oil is gummy or dirty in one jewel and the opposite jewel is clean and freshly oiled.

Capped escape or pallet pivots when flat or rough on one end have the same effect to a lesser degree.

It is never proper to make the end of a pivot flat or rough and thereby shorten and equalize the motion. Neither should the ends of both balance pivots be flattened at any time. On the contrary, the ends of pivots should always be slightly rounded and highly polished: there is no logical reason for having them otherwise.

48. _Short Motion Sometimes Caused by Burr on Opposite Pivot._

There are occasionally instances where a poor motion on one pivot is caused by a slight burr on the opposite pivot. This is usually due to the fact that while the burred pivot is running on its own end stone, there is s.p.a.ce enough between the end stone and jewel to give the burr clearance, but when the position of the watch is reversed, the balance end shake allowance causes the burr to rub on the top of jewel hole and prevents perfect freedom of motion when the good pivot is downward.

49. _Examining the Hairspring._

The hairspring may be true and level but it should be carefully examined to see that there is no possibility of touching at any point.

The observation should take place during the full arc of motion of the balance, for there are some instances in which no rubbing takes place until the motion accelerates. The watch should be held at different angles and the s.p.a.ce between the balance arm and spring, and the stud and spring, closely scrutinized for possible contact. The s.p.a.ce between the spring and over coil at the point where the over coil rises and curves over the spring should be at least equal to the width of the coils and care should be taken to see that the over coil just before the point of rising has the usual s.p.a.ce between it and the next coil. Either position in which the hairspring may rub will have a shorter motion and a gain in time compared to the opposite position in which there is no interference.

50. _Exceptions in Regard to Gaining Rate and Short Motion._

Invariably the arc of motion which is the shortest will gain time compared to the opposite position which has a longer motion. There are, however, some few instances in which there are exceptions to this rule, and knowledge of these exceptions is quite valuable in preventing confusion and doubtfulness in the certainty of making specific alterations. As an example in the horizontal positions; if both end stones are perfect and the freedom of one pivot in the jewel is correct while the opposite pivot has entirely too much freedom, the motion may be somewhat shorter with the proper fitting pivot downward while the rate may be slower compared to the opposite position. This is caused by the balance describing a larger circle when the large hole jewel is upward, as the pivot is allowed to travel a greater distance from the center of the hole as it wavers from side to side during the oscillations.

When the watch is reversed the weight of the balance prevents the pivot from wobbling in the large hole and eliminates the possibility of compensating for the larger circle described by the balance in the opposite position.

The same results are possible when the freedom of both pivots is correct and when one end stone is pitted, as the pit in the stone causes a short motion when downward and prevents the pivot from having any side play whatever, while the opposite pivot enjoys full play to whatever freedom there may be and through this causing a somewhat larger circle to be described by the balance and a slower rate in time.

It should be understood that this does not refer to instances where the end stone surface is merely slightly worn, but to pittings in which the surface of the stone has been actually pierced. In most instances of slight wear the motion will be shorter and the rate fast which conforms to the general rule covering rate and motion.

51. _Detailed Practice._

For preliminary practice in position adjusting, select a watch of about 17 jewels which has just been cleaned and put in order to the best of one's ability.

Regulate it so that it will time within ten seconds in twenty-four hours. Then run it dial up for twenty-four hours and make a notation as to the number of seconds either fast or slow. Next run it dial down for twenty-four hours and make note of the number of seconds fast or slow in this position. If there is a variation in time between the two positions it will be found that the position having the faster rate of the two will also have a shorter arc of motion.[B]

The exact arc of motion in each position can be known by observing the arms of the balance and comparing the extent of the arc with some point on the pallet bridge.

A variation of one-eighth of an inch in motion will generally make a difference of four or five seconds in the rate and greater variations will make corresponding increases in the difference.

When a watch is in good order a correct motion for the horizontal positions is generally considered to be that of one and one-half turn, which consists of three-quarters of a revolution of the balance in each direction.

Should the motion be very much below this, in both positions, there may be something wrong with the general condition of the watch or possibly there may be a weak mainspring at fault, or an imitation spring that is too long and thick may take up too much room in the barrel and cause poor motion as surely as will one that is two weak.