There isn't enough room on this page to cover everything, but it'll get you started.
Learn the basics of jeweling, configuration styles, movement sizes, winding and setting, dial construction, types of adjustments, watch mechanics, railroad standards, and more.
Watch this video to learn the basic parts of a watch and to see how the mainspring torque pushes through the gear train and the escapement to power the balance wheel.
That ticking you hear occurs at a rate of 5 times every second ... 18,000 times an hour ... 432,000 times each day ... 12,960,000 times per month ... and 157,680,000 times a year.
Jewels were used as bearings for polished steel pivots that generated very little friction when properly oiled and maintained.
They were made from industrial-grade precious stones, such as rubies, garnets, sapphires, and even diamonds.
Hole jewels by themselves relied on the flat jewel face to control endshake. Balance wheels use hole and cap jewels, which trap the staffs by their pivot tips. Capped pairs generate less friction because smaller surface areas are in contact with each other.
Jewels were also used in the escapement. The roller jewel, mounted on the balance wheel, gives the impulse to the pallet fork, alternately locking and releasing the entry and exit pallet stones, allowing the escape wheel to rotate one tooth at a time.
A fully-jeweled railroad pocket watch contains seventeen jewels - a total of seven for the balance assembly and a pair for each wheel of the gear train. In 1891 Hampden introduced the first 23-jewel watch in America, and the jewel race was on. Companies added jewels anywhere they could put them, like the mainspring arbor and unnecessary caps on the pivots. There were many jeweling combinations that added up to different totals.
Who had the highest jewel count? The Illinois Watch Co, with 26.
The purpose of jewels is to reduce friction between the gear pivots and the plates in which they rotated. Lesser-jeweled watches can be made to keep accurate time, but any unjeweled pivots of the gear train are still bare metal-on-metal against the softer alloy plates.
Over time the pivots and the bushings can wear badly, especially with poor maintenance or in dusty environments, and once the plate bushings become enlarged the watch is essentially ruined.
American watches used the Lancashire gauge, which is based on the dial plate of a O-size watch measuring precisely a standard inch in diameter as a starting point, with each ascending size adding exactly 1/30th of an inch. The additional 5/30 inches was for the mounting shoulder up to a 16-size watch, when the diameter was increased to 6/30 inches.
Different countries had their own system, adding to the confusion.
Open face was the most common, with the winding stem at the 12:00 position, and was available in every size that American watch companies had to offer. This configuration eventually became a requirement as one of the primary railroad criteria.
Hunter (hunting) placed the stem at the 3:00 position, and was not railroad approved. The cases had a front lid that opened by depressing the crown, several hinges, a dust cover, and springs for the front cover and the latch.
Sidewinders are hunter movements in open-face cases. Seldom purchased this way historically, this arrangement means the original hunting case has likely been melted down.
Most collectors believe this configuration to be incorrect.
Conversion dials allowed hunter movements to be used in an open-face case by moving the seconds bit to the 3:00 position, returning the winding stem to 12:00. These began showing up after WWI, were usually made of metal or melamine, and could be railroad acceptable.
Pendant (or stem-set) is the most common. The watch is wound by twisting the crown; most mainsprings can go roughly 40 hours on a wind. The hands are set by popping up the crown, which did not meet the railroad requirements of the day.
Lever-set watches did meet railroad standards. Setting the time meant removing the bezel and pulling out a small lever, which could be in several different locations around the dial rim. The watch still gets wound by twisting the crown.
Key-wind and key-set watches also didn't meet the railroad requirements. The watch was wound with a small square key through the back and the hands were set by removing the bezel, although a few were able to also set the hands from the back.
Pin-set (or nail-set) watches were largely a Swiss innovation, and the design was seldom used by American companies. They were difficult to set, because the pin must stay depressed while turning the crown. The watch still gets wound with the usual method.
Porcelain-enamel dials were kiln-fired on a copper disc before the characters were added. Single and double-sunk dials were assembled from separate pieces, while one-piece faux dials had depressions milled into their backing plate.
Melamine dials arose from war-time shortages during World War II. An early laminate made with formaldehyde, dials made from melamine have a flat, dull appearance and surface cracks that will only worsen as the material deteriorates.
Aftermarket dials are legitimate items meant to replace damaged originals, made by Swiss firms like LaRose. The tip-offs are 5-minute markings that are too cherry-red, and dial sinks with incorrect diameters and indistinct edges.
Metal (embossed) dials were stamped, milled, or painted, and some were considered railroad grade as Hi-Visibility. Raised numerals, scenic settings, gorgeous patterns, and the fact that they can't crack are the benefits of metal dials.
The growing country moved nearly everything by rail in the 1880s, so an accurate timetable between freights became increasingly important. For decades the railroad companies had generally accepted any 18-size 15-jewel watch for service, but in 1891 the terrible Kipton, Ohio crash killed several people because an engineer's watch had stopped, and the rules changed.
Webster Clayton Ball, a successful jeweler and store owner, was given authority as Chief Time Inspector, overseeing thousands of miles of track . New standards were adopted and by the turn of the century a Railroad Grade watch was American-made, open-face, lever-set, either 16 or 18-size, had a minimum of 17 jewels and was adjusted for temperature and positions. It had to be equipped with a steel escape wheel, a micro-regulator, and a bold-font Arabic dial. Railroad workers were required to submit their watches for regular servicing and inspection, and the most important criteria was that any watch had to be accurate to within 30 seconds a week.
Accuracy was the most important aspect of any watch, so high-grade movements were adjusted to keep better time. These adjustments offset the effects of friction and gravity by fine-tuning the balance assembly, and getting a watch to run accurately took many hours of careful work by a skilled watchmaker. Some companies simply milled 'Adjusted' on the plates, while other firms inscribed the total number of adjustments to which the watch was timed against.
A watch can be oriented pendant up or down, pendant left or right, or the dial up or down. There are nine adjustments - the six positional ones, plus isochronism, plus one each for heat and cold.
The word means "same time" in Greek, and is the accuracy of a watch whether the mainspring is fully wound or almost spent. Barrel stopworks, counter-balanced pallet forks, and longer hairsprings with overcoils all helped to equalize mainspring torque in pocket watches.
Changes in temperature affected both the hairspring and the organic oils in a watch, altering its accuracy. Temperature-sensitive bi-metallic split (cut) balance wheels, new synthetic oils, and the invention of alloy metals (Elinvar) in hairsprings in the 1920s all helped to offset this.
The verge dates to the 1200s and used two pallets mounted 90 degrees apart on the balance staff to alternately lock and release the crown wheel. It was bulky and the mating surfaces wore quickly.
Invented around 1700, the cylinder was part of the balance wheel and utilized half-cutouts to let down the escape wheel. It was much thinner than the verge but was found to have excessive friction.
Also dating from the 1700s, the duplex consisted of tandem escape wheels that required separate impulses to rotate. It could achieve high accuracy but was too sensitive to sudden jarring.
The lever was a form of the earlier anchor escapement used in clocks and was the eventual choice for the railroad era. Its self-starting design was capable of high accuracy with low friction.
The chain-driven fusee was a very simple yet effective method of equalizing drive torque as the mainspring unspooled and lost power. The design dates back to the 1400s, with the earliest versions using gut or wire instead of the delicate chain.
When the watch is fully wound the chain is coiled around the fusee cone and the mainspring is applying the largest force with the smallest leverage. As the mainspring winds down the chain begins to wrap around the barrel, and its weakening pull is applied to the expanding spiral radius toward the bottom of the fusee cone.