Non-Magnetic Watch
A watch whose parts cannot be polarized in a magnetic field; a watch whose quick moving parts are made of some other metal than steel or iron. Paillard, who has studied non-magnetic metals with great care, makes his balance springs of palladium, and his balances of palladium alloyed with copper, silver and other metals. In some instances he appears to have used a palladium alloy for the inner part, and brass for the outer part of the rim, and in others to have formed both laminae of different alloys of palladium. Aluminium bronze, which combines strength with lightness, is particularly suited for the lever and pallets. The American Waltham Watch Company have obtained remarkable results in non-magnetic watches, with an alloy of platinum. Steel in its hardened and tempered form, has long been used for the balance springs of watches, but from the fact that it owed its elasticity to the process of fire hardening, it has always been uncertain in its action, and often two springs from the same piece of steel would give very different results when put to the same tests. This, it is claimed, is not true of the alloy used by the Waltham Company. The non-magnetic spring, they claim, is a natural spring; it requires no rolling or hammering to harden or make it elastic. Its elasticity is a property of the alloy, and from nothing mechanical done to it, and that it cannot be annealed, or robbed of its elasticity, can be shown by heating it to a red heat of nearly 1,100 degrees Fahr., with no change of elasticity. At this degree of heat, steal is annealed, or becomes soft, and of no use as a spring. In the expansion balance of ordinary construction, intended to compensate for temperature, steel is used as the metal of lowest expansion ratio, but in this case never in its hardened and tempered form. Such a balance would be too irregular in its action. No two balances would work alike, and anyone manufacturing such would find a difference of temper or degree of elasticity in each arm of the inside steel laminae. The greatest controlling factor in the expansion balance, is the brass outside laminae, and unless it is hammered or rolled it is of no practical use. A good expansion balance of the usual make depends more on the brass than the steel for its action, and it is a well known fact that brass is one of the most uncertain alloys known, and will often, when not in use, deteriorate to such an extent as to have no value for its original purpose. The Waltham non-magnetic balance is said to stand a change of temperature of 400 degrees Fahr., and return to its original form, as shown by gauges. The non-magnetic balance metals, while having the expansion ratio required, also have a greater natural degree of elasticity than the brass and steel construction, thus making a balance that, when in use in the watch, retains its shape, and will not get out of poise. OIL. One of the most essential things to the good performance and durability of a watch or clock is good oil. A little thought given to the subject of oil will show how very essential it is that only the very best attainable be used. The mechanism of a fine watch, and particularly one of a complicated nature, is expected to perform regularly and with little or no variation, although after a thorough cleaning and oiling that mechanism may not fall into the hands of the repairer oftener than once a year and in the majority of cases it is a longer interval of time. There are few mechanical contrivances from which so much is expected as a fine watch or chronometer, and yet there are none that receive, in proportion to their mechanism, so little care and attention. The engineer carefully wipes and oils his engine at least once a day: the machinist does the same with the lathes and machines under his care, but the watch, a mechanism far more complicated and from which much more is expected in regard to correct performance, does not receive this care oftener, on an average, than once a year. How essential it is then that the lubricant be of the finest possible quality.
The essential requisites of an oil that will insure correct performance of a watch during this time are: 1. It must remain liquid when exposed to severe cold. 2. It must evaporate slowly under intense heat. 3. It must not corrode on metal. 4. It must not become gummy.
What oils best withstand this test? For many years European watch-makers gave the preference to pure olive oil, but experiment has proven that this oil is wholly unfit for watches and the same may be said of all vegetable oils, for they invariably become gummy and turn green when placed in contact with brass. Neat's foot oils were found to possess similar unfitting qualities, and mineral oils are found to evaporate too quickly.
Nothing then remains but fish oils and those made from a species of porpoise known as the black fish, are considered the very best. Fine watch and chronometer oils of this class are prepared from the head and jaw only, which parts yield a limited quantity of very pure oil, known as "jaw and melon oil." This oil is carefully extracted without allowing any flesh or blood to come in contact with it, and after trying is filtered and retained in its native purity as nearly as possible, no bleaching, either by sun, acids or alkalies being employed. There is a popular fallacy existing in the trade that oils should be used when fresh, and even the acknowledged authority, Saunier, says, "do not buy, from motives of economy, bottles that have laid for years in the shop." This may be true and probably is, in regard to vegetable and animal oils, which are likely to become rancid if kept for a long time, but Wm. F. Nye, one of the largest and most celebrated manufacturers of fine watch and chronometer oils in the world, declares that black fish oils are improved by age, and his oils are seldom placed upon the market in the same year as obtained. We are indebted to the same authority for the statement that oils of this kind are clearer and more brilliant after some years than fresh oils. The Nye oils are tried at New Bedford, Mass., and in the following winter are sent to St. Albans, Vt, where it is chilled down and filtered at an average temperature of 25 degree below zero, and in some instances, even as low as 37 degree below zero. In this manner the specific gravity and density of the oil is increased, a finer grain and texture are secured, giving increased resistance to the effects of both heat and cold. The two prominent manufacturers of black fish oils in this country, and we might say in the world, are Wm. F. Nye and Ezra Kelley, both of New Bedford, Mass. The watchmaker should be very careful what oils he uses, as many on the market are acid in tendency and are made from the olive, or are combinations of animal and vegetable oils.