56. _Regulator Pin Practice for Pendant Up Variation._
When the watch is in reasonably satisfactory condition and a three position test proves that the pendant up position has a variation of from ten to twenty seconds either fast or slow compared to the horizontal positions, the regulator pins may be the first point of examination. If there is considerable vibration of the coil between them, and the pendant rate is slow, it will be necessary to close the pins and if the rate is fast and the pins are found to be closed so that there is no vibration of the coil, it will be necessary to spread them slightly. Closing the pins will of course make the general timing of the watch faster and spreading them will make it slower and therefore it will be necessary to regulate the watch for one or two seconds per hour before again testing it in positions. The result of either operation, however, will be to cause the rate in the pendant up position to conform more closely to the horizontal rates.
Preliminary and profitable two position experiments can be made between dial up and pendant up, by having the pins closed on most any watch that is in good order and timing it within five or ten seconds in twenty-four hours, then rating it in these two positions. Next spread the pins slightly, re-time the watch and rate it in the same two positions and compare the variations. A few experiments of this description will soon demonstrate as to the extent of correction that can be obtained in this way.[C] The rule of equal vibration of the coil between the pins after they have been spread must be rigidly enforced.
57. _Pendant Up Corrections Through Poise of Balance._
Assuming that the motion and regulator pins seem to be satisfactory, the next point of investigation should be the poise of balance. The hairspring should be removed and the pivots known to be straight and polished before testing. The rollers are of course a part of the balance and are not to be removed. A perfectly poised balance can be stopped at any point on the tool and it should at least remain stationary at each of the four quarters of its circumference. No. 28, Chapter VII, should be consulted for details on poise corrections.