The hairspring was pinned at the usual fast point as per illustration in Fig. 9, Chapter VIII. The most positive alteration to be made under the circumstances was to break off the spring at the collet and repin it at about 45° above the horizontal line. This would be slightly approaching the slow point as explained in detail in Chapter VIII, No. 35.
The mean rate of the watch would necessarily be faster after shortening the spring; the mean time screws were found to be turned in close to the rim and were each turned out about one full turn to compensate for the gain. The poise was tested and found to remain correct and the next position test showed a variation of four seconds as per sixth column Fig. 26.
The total time required for the alterations was about one hour.
[72.]Example No. 10.
Illinois. No. 1,483,023, Open Face, 21 Jewels.
Repairs made. Trued and poised balance, new balance jewel and cleaned.
This example has been selected for the purpose of illustrating a test in the sixth or pendant down position and to give a practical demonstration showing that the rates in the pendant down and pendant up positions can be reversed, with positive results, through reversing the collet pinning point of the spring, as covered in "Relative Pinning Points" Chapter VIII.
This alteration can be undertaken with assurance of results even though there may be serious errors of construction in the watch.
The first five position test proved that the rate pendant up was extremely fast compared to all other rates as per second column Fig. 27.
Investigation proved that the hairspring was properly centered and pinned at the fast pendant point and that the regulator pins were slightly spread with equal vibration of the coil between them. The motion was about one and one-fourth turn pendant up and over one and one-half turn in the horizontal positions when the mainspring was nearly full wound. The ends of balance pivots were found to be perfectly flat, which was no doubt due to an effort to produce a faster rate in the flat positions to cause them to compare more favorably with the pendant up rate. This, however, was unsuccessful as indicated by the rate.