Hampden No. 1438676, Open Face, 21 Jewels.
Repairs made. New balance staff and hole jewel fitted and cleaned.
The first position test showed a variation of twelve seconds slow pendant up as per second column Fig. 19.
| No. ...1438676.......... Make...Hampden......... | |||||||
|---|---|---|---|---|---|---|---|
| D U | + 2 | + 2 | + 2 | + 2 | P | ||
| D D | + 4 | + 2 | + 6 | + 4 | |||
| P U | - 6 | -10 | + 9 | + 3 | |||
| 12 | 2 | ||||||
Investigation found all points such as balance true, hairspring true, level and circle and the regulator pins reasonably satisfactory. The motion, however, was not as good as it should have been when the spring was nearly wound up. It was let down to where it would ordinarily be after about twenty-hours run and found to have barely one turn pendant up and a trifle over one turn in the flat positions. This proved that the motion was not satisfactory for a watch that had just been put in order and all pivots were examined for close end or side shake; they were found to be satisfactory and the mainspring was removed for examination and found to be somewhat set and about 0.01 mm. thinner than those generally used for this grade watch. A new mainspring was fitted and the motion was improved by about one-fourth of a turn and the next position test showed a variation of two seconds as per fourth column Fig. 19. The time consumed in examination and changing the mainspring was about twenty-five minutes.
The three position limit of variation allowed by most manufacturers and railroad inspectors is seven seconds from one position to any other. Records of thousands of watches on which the work has been carefully done in putting the watches in order, show that about seventy per cent of the watches will rate within five seconds in the three positions without making alterations and that only ten per cent will be close to the limit of seven seconds, while about twenty per cent will require alterations such as shown in the four examples above. (See Chapter XII, No. 60.)
One or two more examples might be introduced to show variations and corrections between dial up and dial down; this feature has been pretty well covered however in Chapter XI, and five position example No. 9 also shows a variation of the horizontal rates with correction.