The Watch & Clockmakers' Handbook - Frederick James Britten

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1881 edition. Excerpt: ... Useful Memoranda. Timing French Pendules.--Escape wheels of French pendules make two revolutions a minute, or four vibrations to each tooth. They may be quickly brought to time by counting if the beats of pendulum per minute equals four times the number of teeth in scape wheel. Timing Repeating Carriage Clocks.--The quickest method is to listen to the first blow of the hammer on the bell (or gong) at each hour and half-hour, noting at the same time the position of the seconds hand on the regulator. Thus: supposing the blow is given exactly at 12.0'0," make a note of it, and compare again at 12.30'0," when probably the half-hour blow will be given at 12.30'5"; make a note of this also, but do not alter the index, as this difference arises from the imperfect position of the half-hour pin in canon wheel; at 1.0'0" compare as before, and as it is the same pin coming into action as at 12.0'0," any difference in the time of the first blow will be indicative of a gain or loss, as the case may be; thus: it may be given at 1.0'4" which will show a loss of 4" in the last hour, and the clock may be now regulated accordingly. The blow may next be given at 1.30'8," showing the effect the moving of the index has had in making it gain 1" in the preceeding half-hour; regulate and compare again at 2.0'0," and if the first blow is given at 2.0'3" it will show that the clock has been keeping correct time for the last half-hour. To Widen a Jewel Hole.--Chuck the hole in the lathe with cement. Place a spirit-lamp underneath to prevent the cement hardening. Hold a pointed bit against the hole while the lathe is running until the hole is true, when remove the lamp. The broach to widen the hole should be made of copper, of the size and shape required, and the...