W. H. Samelius, Chairman
Science of Horology and Technical Board
Answer: Analysing your question, I would suggest you check the corner freedom between the roller jewel and corner of your fork slot. It is possible that the roller jewel is not set square and upright. If the roller jewel is set out of square, the knocking action you mention coming from one direction only might be that the corner of the roller jewel strikes above the corner of the fork slot. By squaring up the roller jewel, the knocking sound will disappear. Then again, the banking screws may be open, giving too much angular motion to the lever so when jewel pin is about to enter, it strikes the curved part of the horn just beyond the corner of the fork. This can be remedied by closing the banks. I am assuming that the side shake for balance pivots are close and that the balance wheel is true, so the arm of the balance does not strike some slight projection of the pallet bridge or pallet bridge screw. Balance pivots with excessive side shake could also give the same trouble as the jewel pin will not enter both sides of the fork slot alike. These are suggestions I trust may prove helpful in locating your trouble.
RWH: If the upper and lower balance pivots are perfectly round and fit the jewel correctly but are of different diameters, will it effect the rating of the watch?
Answer: Pivots of unequal size will result in unequal friction and when the watch is run in dial positions, you will invariably find that the watch will show a faster rate on the larger pivot as compared to the smaller pivot.
ELS: I have several small hard oilstone slips that have become worn, the corners being rounded and the surfaces grooved. How can I restore them to usefulness?
Answer; Procure a sheet of plate glass and with some fine flour emery and water a new surface is quickly acquired. If the stone is badly scored, use a coarses emery powder for quickly rubbing down and then finish with fine powder.
PMI: I have heard about German Silver, what is its composition and is there any silver in it.
Answer; German silver does not contain silver as implied. The proportions commonly given are copper 50 percent, nickel 25 percent and zinc 25 percent. These proportions however, may be varied to suit the various uses for which the German silver is to be used. Varying the proportions will alter the hardness, ductility, mallability, surface polish, elasticity or electrical conductivity.
"So as to be certain when her husband, who works nights, gets in, a woman in Maryland has established the rule that he must punch a CLOCK."