Things Worth Knowing

From The American Horologist magazine, January 1939

Things Worth Knowing
By REV. FRANCIS BIMENSKI

MORITZ Grossman, the celebrated horologist (died 1885), while still young, used to pause and ponder while repairing watches, much to the despair of his employer. His object was to recall the principles taught by the masters and thus to verify the theory in life, and again, to try the abstract rule in concrete cases. He knew well that this inference from the theory to the practice, and again, from the practice to the theory opens our eyes to new experiences and paves the road to genuine progress.

Such an intelligent overhauling, so highly recommended, often becomes a dire necessity. Indeed, factories, fearing expenses in the changes of costly machinery, may allow minor imperfections to pass; or again, an unlucky hand may have tampered with the delicate mechanism and thus created serious conditions. In those cases, the watchmaker will have to pass judgment and distinguish the right from the wrong in order to correct the mistakes without creating new ones. This self-examination is a test of our actual correct knowledge. It will reveal to our astonisment how vague our thoughts and reasonings often are and will fit us for better work.

For experiment sake, it is well to take a carefully constructed watch; for instance, a Hamilton, size sixteen, with 21 jewels, the pride of the R. R. men, and observe closely every part, recalling at the same time the principles taught by the masters.

We are familiar with the lever-escapement, the survivor of one hundred kinds of escapements. It is called, too, the semi-detatched or the king of escapements. It was invented by Hook (1650) and perfected by Graham (1690). However, since Mudge left us the first definite description (1799), history reserved for him the honor of posterity. Quite naturally this escapement underwent many change in the course of years.

For instance, Mudge's pallets embraced five teeth out of twenty, and the hairspring is not the kind of modern times. But each master tried his hand, adding, but mostly simplifying, as the last famous watch-collection of Major Chamberlain clearly shows, until the last stage of perfection was reached in the model of today.

The Balance

The modern balance, or vibrating wheel differs from the simple balance of old. It has two loosely curving arms of two metals (brass and steel) fused together. The two-metal system was first introduced by LeRoy (1766) and perfected by Arnold & Earnshaw. The obliquely cut allows the stretching or shortening of the metal at low or high temperatures, and thus gives a way of compensation. In fact, the same heat that weakens the elasticity of the hair spring will curve in the loosened arms, diminish their diameter, and quicken the motion of the balance. The error is thus corrected. Quite naturally the proportion of steel and brass must be in such proportion as to offer equal resistance to bending and sensibility. This compensation is not perfect. The so-called middle temperature error survives (Berthoud 1775).

High-grade balances are made of nickel-steel and are called monometallic or integral. The alloy is the famous Invar of Didisheim, "Invar" (iable) in heat and cold (1899). The arms are not cut, because little compensation is needed. I say "little," because Didisheim and others tried to add delicate auxiliary attachments to reach a higher perfection.

This compensation process is still studied more carefully. The Elgin Invar Steel Balance of Raymond (1924) has bi-metallic rims, brass and Invar, and the curve of the angle has 35 instead of 13 degrees. Of late Mr. Volet proposed a brass bar and steel rim while Strauman advocates the monometallic rolled zinc alloy, The screws, of various composition (brass or gold), of various sizes and weights, are distributed around the circumference (five to eight on each side).

Weight determines the number of vibrations. It seems to me that the constellation of the screws must affect the vibrations; in P V position, for instance, if too many are grouped together in one place. We might therefore distinguish a static and kinetic equilibrium. The size of the balance will influence the swing, which ought to be vigorous and yet constant. Thus we notice that Hamilton watches show fair sized balances.

Elgin realized this point, putting an 18 size balance into a 16 size watch in one of the latest models (1927?). The horological schools of Switzerland worked out several tables to determine the classical (Geneva quality) size and weight. I don't know how American factories treat those learned tables. But I know that the Swiss are the masters of delicacy and elegance, while the American in his practical turn of mind is rather for models that will stand the wear and tear and has the balance heavier.

The qualities required of a wellformed balance are obvious: perfection in poise, perfection the flat and in the round. Poising means equal distribution of weight around the circumference. The good poising tool, or even a depthing tool, will detect any fault. The test at each quarter is considered fair, though not necessarily perfect. Perfection in the flat and in the round is tested with calipers and corrected by means of special tweezers and pliers. Trained thumbs and fingers are good natural pliers for that purpose.

The Staff

The balance is lightly yet firmly rivetted to a staff. The staff is a little complicated axle or shaft. It gives a firm seat to the balance, has to hold fast the hairspring and besides one or two rollers. High grade staffs have a groove to keep the oil in its place and hinder its spreading. The two cony ends rotate between the walls of two hole jewels and two cap jewels with a side and end play of .03 mm. The Swiss prefer the rounded ends; Elgin seems to prefer flat ends, thus giving a chance for slight adjustments.