W. H. SAMELIUS, Chairman
Science of Horology and Technical Advisory Board
What are they for?
Answer - When fitting a cover to the barrel, the barrel proper is cemented in the lathe and trued to the hole. The cover is then snapped on and the hole in the co v e r is then bored to the proper size. The indicating marks are then p lac e d on the cover and barrel so the assembly will be the same at all times.
This procedure assures us that the barrel will run perfectly true in the round and flat. In other words, the barrel will be perfectly upright.
R.W.A.- I have a watch where the cannon pinnion is lost. The minute wheel has 30 teeth, the minute pinion, 8 leaves; the hour wheel, 32 teeth. How can I determine the proper number of teeth for the cannon pinion?
Answer - While the minute hand revolves once per hour, the relation between the minute and hour hand is 12 to 1. That is, the cannon pinion must make 12 revolutions while the hour wheel goes once. As there are 32 teeth in the hour wheel and the minute pinion has 8 leaves, that would be a 4 to 1 ratio. Then, as the minute wheel has 30 teeth, we would have to have a pinion that would equal a three to one ratio and one third of 30 teeth would call for a 10 leaf cannon pinion.
T.E.W. - What is the quickest way to close holes in barrel which are not much worn and should properly be closed.
Answer - Select a stump with a slight hollow cone center, one that the bossing of the barrel will almost drop in flush. Then with a wide flat punch, drive the bossing down into the hollow center, contracting the metal, or closing the hole. You can then ream and polish the hole with a round broach.
P.E.M. - Can you tell What makes a watch gain dial up and dial down and keep time pendant up?
Answer - You will undoubtedly find that the ends of the bal pivots are flat which always cause the watch to run fast due to the friction causing a short arc or quick excursion. If you slightly round the end of the pivots, the friction will be brought nearer to center, allowing the balance to take a longer arc, causing a losing rate.
S.O. - I have several oilstone slips which have become rough and grooved. Can I restore a smooth surface.
Answer - The oilstone slips may be rubbed down smooth on a plate glass using medium emery and water and for final finish use flour emery with water.
R.S. - I have trouble in getting a bright cut on platinum and other metals. What do you recommend
Answer - When bright cutting, the graver should be polished with the cutting edge, that is, so the polished lines run parallel with the cutting edge. Some engravers use ordinary laundry soap dissolved in turpentine, with a consistency of vaseline, dipping the graver in this mixture for lubrication, will give a bright cut.