60. _Percentage of Watches Requiring Correction of Position Rates._
In constructing this chapter and the preceding one it has been preferred to go into detail for the purpose of defining the possible corrections and alterations, together with the results to be expected.
Not every watch demanding position correction would require the extent of investigation and possible alteration that is pointed out and in most instances the direct cause will be disclosed with very little investigation. In fact, the experienced adjuster can tell almost immediately where to look for trouble by merely observing the position rate as entered on the card.
It should also be clearly understood by the student that when the repairing and cleaning of high grade watches is done by one who understands the details of adjusting, there will be only a very small proportion of the watches requiring position corrections. As a rule among experienced adjusters there will be about seventy per cent of the watches that will have very close rates. If, therefore, one hundred watches are put in order and tested in positions there should be seventy that do not require any correction, while about thirty will require either minor or major alteration. The time required for making alterations on this thirty per cent of the watches will be offset by a smaller percentage of unsatisfactory returns and a better reputation for doing good work.
FOOTNOTES:
[Footnote C: See Chapter IX, on Regulator Pin Alterations.]
CHAPTER XIII
CONCRETE EXAMPLES SHOWING DEFINITE THREE POSITION ALTERATIONS AND LABOR UTILIZED
61. _Order of Position Timing and Method of Calculating the Variation._
In submitting the previous chapters it is a.s.sumed that the average ambitious watchmaker will gain enough knowledge from the various details to enable him to understand the meaning of the adjustment of watches, the causes of variations and the princ.i.p.al alterations for obtaining corrections.
There are many features covered that will enable him to develop in practice and to experiment in individual points of importance, without running up against mathematical deductions that halt and discourage further interest in the subject.
To understand the principles const.i.tutes a large percentage of the qualifications required and to be able to execute the practical alterations and corrections required in different kinds of variations completes the general qualifications. It would hardly be sufficient, however, to conclude the work at this point without giving more definite examples for comparison, together with some indication as to the approximate time that may ordinarily be utilized in doing the work and also showing some instances of a possible choice of several alterations and why a particular alteration is advisable. For this reason the following examples will be found to have an important part in fulfilling the mission of this book.
In selecting these examples the fineness of results has not been the princ.i.p.al consideration. The deciding factor was the differences in variation and alterations, and the fact that they cover the widest field for general instruction that could be selected from hundreds of equally good rates among various models of watches which, with three exceptions, were put in order for railroad service.
The method of computing the variation from one position to any other is similar to that used in temperature adjusting as described in Chapter 3, No. 13. The watch should first be timed closely and then rated for twenty-four hours in each position. It should be wound before being started in each position but should be set only on the first day so that the time is never disturbed.
The first position to be rated is universally Dial Up, then in succession Dial Down, Pendant Up, Pendant Right and Pendant Left. The daily total number of seconds fast or slow should be entered in the first column of the rate card after each twenty-four hours run. This column then const.i.tutes the progressive rate from which the actual variation between the different positions is ascertained.
The figure in the upper square is first carried out to the adjoining column at its full value and then the difference between this figure and that of the second square is entered in the second square of second column, and so on until the difference between each of the succeeding squares of first column is registered in the second column.
If the figure in a square of first column is greater than that in the preceding square the carried out figure would be entered in second column as + If the figure is less than the preceding square it would be carried out as-.
The total variation in positions is obtained from the figures entered in second column. If these figures are all entered as either plus or minus it is necessary to merely subtract the lesser figure from the greater. If, however, some figures are entered as plus and others as minus it will be necessary to add the greater figure of each of the two denominations.
62. _Example No. 1, Three Positions._
Columbus, No. 358846, Open Face, 17 Jewels.
Repairs Made. New balance staff, two balance screws changed, hairspring trued and cleaned.
After timing the watch closely it was tested in three positions and found to have a variation of eleven seconds fast pendant up as per second column, Fig. 16.
Fig. 16
+--------------------------------------------------+No. _358846_ Make _Columbus_+--------+-----+-----+-----+-----+-----+-----+-----+D U+ 1+ 1+ 4+ 4P+--------+-----+-----+-----+-----+-----+-----+D D0- 1+ 7+ 3+--------+-----+-----+-----+-----+-----+-----+P U+10+10+14+ 7+--------+-----+-----+-----+-----+-----+-----+-----+ 11 4
Investigation showed the hairspring to be pinned nearly correct, true level and in circle; balance true; regulator pins closed and motion satisfactory. A correction could have been made in one of several ways; either by making a slight alteration of the pinning point at the collet; correcting a possible slight error in poise or by slightly spreading the regulator pins.
As the extent of variation did not indicate any serious error at any particular point for a watch of this description the possible poise error and the slight variation in the pinning point were waived and the regulator pins were spread just enough so that slight equal vibration of the coil could be seen with a double eyegla.s.s. After this alteration the mean time was found to be one second per hour slow which was corrected on the mean time screws and the next test showed that the variation had been reduced to four second as per fourth column, Fig. 16. The time consumed in making the alteration aside from the repairing was less than ten minutes.
63. _Example No. 2, Three Positions._
Ball No. B060816, Open Face, 17 Jewels.
Repairs made. Refinished balance pivots and cleaned. The first test in positions disclosed a variation of thirty-five seconds as per second column Fig. 17.
Investigation found the balance true; hairspring true, level and circle; regulator pins very nearly closed and the motion one and one-eighth turn. This rate like example No. 1, was also fast in the pendant up position, but the greater extent of the error indicated that there must be some serious poise error, and upon investigation this was found to be the case. A screw on the roller jewel side or at the bottom when the balance was at rest was found to be heavy. This was corrected and the next test showed a much improved rate although there was still a variation of eight seconds fast pendant up as per fourth column Fig. 17.
Fig. 17
+--------------------------------------------------+No. _B060816_ Make _Ball_+--------+-----+-----+-----+-----+-----+-----+-----+D U+ 2+ 2+ 7+ 7+ 7+ 7P+--------+-----+-----+-----+-----+-----+-----+D D+ 20+14+ 7+14+ 7+--------+-----+-----+-----+-----+-----+-----+P U+37+35+29+15+24+10+--------+-----+-----+-----+-----+-----+-----+-----+ 35 8 3
A better rate than this was desired and further examination proved that the locking of the pallet stones and escape teeth was quite strong and caused the pendant up motion to have a shorter arc than would have been entirely desirable. An alteration was made by pushing the receiving stone further back into the slot and rebanking the escapement. The third position test showed an improved motion and a variation of three seconds as per sixth column. The total time required for making the alterations was about three quarters of an hour.
64. _Example No. 3, Three Positions._
Elgin No. 7457488. Open Face, 21 Jewels.
Repairs made. Cleaned; polished pivots and new mainspring fitted. The first position test showed a variation of nineteen seconds as per second column, Fig. 18.
It will be noted that this example differs from Nos. 1 and 2, in that the rate is slow in the pendant up position. Examination showed all points satisfactory except that the regulator pins were spread considerably and allowed too much freedom of vibration for the coil.
Had this vibration been slight it would have been advisable to examine the poise. As it was considerable, however, the alteration made was to close the pins so that only slight vibration was visible with a strong gla.s.s.
Fig. 18
+--------------------------------------------------+No. _7457488_ Make _Elgin_+--------+-----+-----+-----+-----+-----+-----+-----+D U- 9- 9+ 5+ 5P+--------+-----+-----+-----+-----+-----+-----+D D-18- 9+ 8+ 3+--------+-----+-----+-----+-----+-----+-----+P U-46-28+ 9+ 1+--------+-----+-----+-----+-----+-----+-----+-----+ 19 4
This watch was not equipped with mean time screws and it was therefore necessary to fit a pair of thin timing washers because closing the pins caused a gaining rate of two seconds per hour in the mean time.
The next position test showed a variation of four seconds as per fourth column Fig. 18.
The time consumed in making the alteration and fitting the washers was about ten minutes.
65. _Example No. 4, Three Positions._
Hampden No. 1438676, Open Face, 21 Jewels.
Repairs made. New balance staff and hole jewel fitted and cleaned.