Investigation proved that the motion dropped off considerably after a few hours run and that the mainspring was too weak for this grade of watch. A proper mainspring was fitted which in turn corrected the motion, but the next test in positions proved that there was still a variation of eighteen seconds as per fourth column Fig. 24.
Fig. 24
+--------------------------------------------------+No. _10504112_ Make _Waltham_+--------+-----+-----+-----+-----+-----+-----+-----+D U00- 2- 2- 1- 1P+--------+-----+-----+-----+-----+-----+-----+D D00- 5- 3- 10+--------+-----+-----+-----+-----+-----+-----+P U+14+14-21-16- 4- 3+--------+-----+-----+-----+-----+-----+-----+P R+ 4-10-19+ 2- 5- 1+--------+-----+-----+-----+-----+-----+-----+P L+16+12-25- 6- 3+ 2+--------+-----+-----+-----+-----+-----+-----+-----+ 24 18 5
The balance and spring were removed and considerable poise trouble was discovered. The trouble was at different points of the balance and no one location seemed to be heavy at all times. The balance pivots were carefully gauged with a metric micrometer and found to be out of round, or to be exact, more oval in form than cylindrical. A new staff with round pivots was fitted, after which the balance was easily poised and the next test showed a variation of five seconds as per sixth column Fig. 24. The total time required for making the examination and alterations was about one hour.
70. _Example No. 8._
Vacheron and Constantin. No. 272,854, Open Face, 21 Jewels.
Repairs made. New balance staff, hole jewel, cap jewel, gla.s.s, and cleaned.
The first test after making the repairs showed a variation of twelve seconds as per second column Fig. 25.
It will be observed that the rates in the horizontal positions are on the fast side and those in the vertical positions are on the slow side. In this instance the hairspring developed to the left from the collet similar to the ill.u.s.tration shown in Fig. 10, page 45.
Fig. 25
+--------------------------------------------------+No. _272854_ Make _V. & C._+--------+-----+-----+-----+-----+-----+-----+-----+D U+ 2+ 2- 4- 4P+--------+-----+-----+-----+-----+-----+-----+D D+ 5+ 3- 8- 4+--------+-----+-----+-----+-----+-----+-----+P U- 1- 6-14- 6+--------+-----+-----+-----+-----+-----+-----+P R- 8- 7-21- 7+--------+-----+-----+-----+-----+-----+-----+P L-17- 9-25- 4+--------+-----+-----+-----+-----+-----+-----+-----+ 12 3
Investigation found the escapement, regulator pins and pinning point satisfactory; the motion was one and one-fourth turn in the vertical positions when fully wound and only a trifle less when partially let down. In the flat positions, however, the motion was very little better than in the vertical, which indicated either pivot or end stone trouble as under normal conditions the flat motion would be about one-fourth turn greater than that of the vertical.
Inspection of the end stones proved that they were satisfactory but the ends of the balance pivots were found to be somewhat flat and not perfectly polished.
The ends of the pivots were slightly rounded and highly polished, the jewels and end stones cleaned and reoiled and the balance replaced, after which the motion in the flat positions was one and one-half turn with the mainspring fully wound and only slightly less when partially let down.
The motion in the vertical positions was also slightly improved and the next test in position showed a variation of three seconds as per fourth column Fig. 25.
Time required for making the above alteration was about one-half hour.
In the study of this example it should be clearly understood that when the ends of balance pivots are flat, burred or not well polished, or when the end stones are dry or dirty the motion in the horizontal positions will be shorter than normal and this will always cause the rate to be faster than it should be. Acceleration of the motion in such instances by means of refinishing the pivot ends or by cleaning and reoiling the jewels and end stones will always produce a slower rate through causing a longer arc of motion.
This point is covered in Chapter XI, No. 47.
71. _Example No. 9._
E. Howard. No. 1,116,735. Open Face, 23 Jewels.
Repairs made. New balance staff; hole jewel; mainspring and cleaned.
The first test in positions showed a variation of eleven seconds. The rate in all positions was fast with the exception of the dial down rate, which was slow. See Fig. 26.
At first glance it might appear that by causing a faster rate of six or seven seconds in the dial down position the watch would have a very good rate. This, however, would not be consistent unless the rate was due to the exception referred to in Chapter XI, No. 50.
Examination of the motion in the horizontal positions proved that it was about one fourth turn better in the dial down position than it was in the dial up position which rate compared very closely with the vertical positions. It was therefore evident that the dial up rate was not true and investigation found the oil in the upper jewel had become thickened by the entrance of dirt which caused the short motion and fast rate when the balance was running on this end stone.
Fig. 26
+--------------------------------------------------+No. _1116735_ Make _E. Howard_+--------+-----+-----+-----+-----+-----+-----+-----+D U+ 2+ 2- 5- 5+ 2+ 2P+--------+-----+-----+-----+-----+-----+-----+D D- 3- 5-10- 5+ 4+ 2+--------+-----+-----+-----+-----+-----+-----+P U+ 1+ 4- 6+ 4+ 9+ 5+--------+-----+-----+-----+-----+-----+-----+P R+ 7+ 60+ 6+10+ 1+--------+-----+-----+-----+-----+-----+-----+P L+ 9+ 2+ 2+ 2+14+ 4+--------+-----+-----+-----+-----+-----+-----+-----+ 11 11 4
After thoroughly cleaning the jewel, end stone and pivot, the motion in the dial up position was improved and equaled that of the dial down position.
The next position test showed the horizontal rates to be equal but the variation of eleven seconds in the five positions still existed as per fourth column Fig. 26. The vertical rates were all fast compared to the horizontal; the regulator pins were found to be slightly open which prevented a correction at this point. The locking of the escapement was examined and found to be satisfactory, so the balance was again removed and tested for poise which was also found satisfactory.
The hairspring was pinned at the usual fast point as per ill.u.s.tration in Fig. 9, Chapter VIII. The most positive alteration to be made under the circ.u.mstances 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 ill.u.s.trating 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 a.s.surance 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.
It is quite possible that if the watch ever was closely rated it was due to counterpoise of the balance as with the present rate the poise, escapement and regulator pins were satisfactory and did not admit of further corrections that would be of advantage.
By examining the P. U. rate in second column Fig. 27, it will be found to be twelve seconds fast and then by referring to the separate P. D.
(Pendant Down) rate at the bottom, it will be found to be four seconds slow. Adding these figures gives a total variation of sixteen seconds between these two positions.
Fig. 27
+--------------------------------------------------+No. _1483023_ Make _Illinois_+--------+-----+-----+-----+-----+-----+-----+-----+D U- 3- 3- 1- 1P+--------+-----+-----+-----+-----+-----+-----+D D- 8- 5- 2- 1+--------+-----+-----+-----+-----+-----+-----+P U+ 4+12- 6- 4+--------+-----+-----+-----+-----+-----+-----+P R0- 4- 4+ 2+--------+-----+-----+-----+-----+-----+-----+P L- 6- 6- 7- 3+--------+-----+-----+-----+-----+-----+-----+-----+P.D.- 4 +11+--------+-----------------------+
Now if these rates were reversed and the P. D. rate was in the place of the P. U. rate the watch would have shown a very good position rate in the first five positions and the greater part of the sixteen seconds variation would have been in the pendant down position where it would be of the least disadvantage. In order to obtain this condition the collet pinning point was changed from the fast to the slow point, or from "E", Fig. 9, to "G", Fig. 11, Chapter VIII.
A pair of heavier screws were fitted to the balance to compensate for the difference in time caused by shortening the spring and the next five position test showed a variation of six seconds. A separate pendant down test proved that the pendant up and pendant down rates had been practically reversed as shown in the fourth column.
73. _Causes of Extremely Fast Vertical Rates._
Extremely fast pendant up rates are not particularly unusual, although the causes and corrections may be widely different.
For instance, the poise and motion feature, No. 28, Chapter VII, may be responsible, or the balance may be in poise and the collet having a wide slot may cause out of poise and be responsible if the slot is located at the proper point. A defective escapement or regulator pins tightly closed may also be responsible. Should these points be found satisfactory, however, the rate is generally due to one of three causes.