Pocket watch terminology [Archive] - National Association of Watch and Clock Collectors Message Board

Kent

11-13-2007, 10:57 PM

RJ

Several glossaries, or descriptions, of watch terms are available online:
John Duvall's Components of a Pocket Watch (http://nawcc-***-mb.infopop.cc/helphand/pwc/pw01.html),
CWR Technical Pages (http://www.cwrnh.com/techpages/cwr_technical_pages.htm) on the Carignan Watch Repair Company, Inc. website.
The Time Zone has an excellent Glossary of Watch Parts (http://www.timezonewatchschool.com/WatchSchool/Glossary/glossary.shtml),
The Horology WebRing offers The Watch-Collector's Paradise (http://www.datacomm.ch/rbu/index.html),
The Watch Cabinet has A Brief Glossary of Technical Terms (http://www.horologia.co.uk/watchglossary.html).

Unadjusted
Unadjusted movements are those for which no effort has been made to adjust the watch to temperature or position. Or, no provision has been made to allow for these adjustments. Whatever variation in the timekeeping rate results from a change in temperature, or the position in which the watch is carried, exists as a result of the way that the particular watch was built. This has to be accepted as the best that watch the can do. Fortunately, just about all of the mass-produced, jeweled, American, unadjusted watches could keep time within a few minutes a day.

A lack of the marking "Adjusted" is significant. Although the term is vague and may mean anything from adjustment only to temperature, to adjustment to temperature, isochronism and six positions, and although some companies avoided higher duties on imported movements by not marking a movement "Adjusted," the lack of the marking generally indicates a lower grade movement.

Adjustment
Movements that are marked to be "Adjusted" may have a variety, or combination, of features. One has to read the factory specification for any given movement grade to discover just what level of adjustment is being claimed. High grade watches built after 1905-1908 may be marked with specific adjustments. This is especially true for watches intended for use in railroad time service. The purpose of all of these features is to keep the balance wheel (the wheel that spins back and forth rapidly), as nearly as possible, oscillating at a consistent rate. The consistency of the rate of oscillation of the balance (wheel) is the timekeeping quality of the watch.

Temperature Compensated Balance (wheel)
A balance wheel that is temperature compensated has the rim made of two dissimilar metals. There are usually two arms (spokes) from the hub supporting the rim and there is a slot cut in the rim just past each arm. This forms two rim segments having one end supported by the arm and the far end free to move. These slots, and the two colors of metal in the rim, are identifying characteristics. As the temperature increases, lessening the power of the hairspring (the spring coiled inside of the balance wheel), the far ends of the rim segments deflect inward. As temperature decreases, the segment ends relax, moving outward, as the hairspring strength increases. The action is much like an inexpensive thermostat in the home. This movement of the rim segments changes the moment of inertia of the balance wheel, compensating for the alteration in the hairspring strength.

Adjustment to Temperature
This is sometimes referred to as adjustment to heat and cold. It requires a temperature compensated balance. The balance has pairs of screws (180 degrees apart) set into the rim. These give the balance mass, which sets the basic rate at which it oscillates. One pair may be the meantime screws (which can be identified - if present - by being longer than the other screws), used to bring the rate deviation to minimum (with the regulator in its center position) after all of the other adjustments have been made. The locations of most of the pairs of screws (each pair is 180 degrees apart) on the balance wheel rim are chosen to provide the best match of change in moment of inertia to change in hairspring strength (there are extra pairs of holes so that the screws may be moved to the best possible positions). The object is to keep the balance wheel oscillating at the same rate over the specified temperature range.

Adjustment to Position
The next level is adjustment to position. This is adjustment to maintain the same rate of balance wheel oscillation, regardless of which of the specified positions the watch is in. There are a total of six positions. Unfortunately, the number or the positions to which the watch is adjusted isn't specified for most watches built prior to 1905-1908. Typically, unspecified adjustment to position means adjustment to three positions, but there are a number of instances in which it means five positions. Adjustment to three positions most likely means stem up, stem at the 3 o'clock position and stem at the 9 o'clock position.

In discussing adjustment to positions (on the NAWCC Pocket Watch Message Board, 26-Aug-06), John Runciman, quoting from the book Watch and Clock Information Please W. H. Samelius” by O. R. Hagans, posted a definition of adjustment to four positions as dial up, stem up, stem at the 3 o'clock position and stem at the 9 o'clock position. John also pointed out: "For those not familiar with W. H. Samelius he organized the Elgin watchmakers College in 1921 and served as its dean for 33 years." It was also stated in O. R. Hagans' book that adjustment to two positions was defined as dial up and stem up, while adjustment to one position was stem up with watch inclined 45 degrees to the rear The marking "Adjusted 2 Positions" is only occasionally seen, seemingly only on low grade Swiss watches. An indication of adjustment to one position is almost never seen.

Watches adjusted to five positions include the three positions of stem up, stem at the 3 o'clock position and stem at the 9 o'clock position, plus the dial up and dial down positions. Robert Sweet once posted several pages from the 1914 edition of the Hamilton Timekeeper which lists the five positions in order as (1) dial up, (2) dial down, (3) stem up, (4) stem at 9 o'clock and (5) stem at 3 o'clock. The 6th position is stem down at the 6 o'clock position. These positions are illustrated in a 1924 Illinois Ad (http://photos5.flickr.com/9939069_a6655c13df_o.jpg)'. Since temperature variation is usually greater than positional variation, watches marked to be adjusted to position include adjustment to temperature. A high grade Swiss watch marked to be adjusted usually implies adjustment to all positions. "All" may be 5 or 6 positions.

Some watches are marked “8 Adjustments.” Depending upon the manufacturer’s specification at the moment that the watch was made, this can mean adjustment to temperature, isochronism (see below) and 6 positions. Or, it may mean adjustment to heat, cold, isochronism and 5 positions. To clear up the ambiguity, in the early 1950’s, Elgin marked its top (and only) railroad pocket watch “9 Adjustments.”

The marking "Adjusted" on a movement means whatever the manufacturer said it meant at the time that the watch was built. Lacking descriptive factory literature, we have no way of knowing what that means today. Unless a watch is specifically marked as to the number of positions to which it is adjusted, such as a watch that is only marked "Adjusted," the only way to know that number (if it is adjusted to positions at all) would be to identify the grade and find the manufacturer's description of the position adjustment for that grade. For example, the U.S. Watch Co. of Waltham's "The President (http://www.pockethorology.org/Railroad/Fig_22.jpg)" grade is only marked "Adjusted" (in the 9 o'clock position - right at the junction of the two damaskeened circles), yet U.S. at Waltham's Description (http://static.flickr.com/81/232636996_7ddbfe9d93_o.jpg) states that it is "adjusted to heat, cold, isochronism and all positions, ..." Another example is Waltham's grade No. 35 (http://static.flickr.com/87/232643281_952b435b57_o.jpg), which is only marked "Adjusted." The Description (http://static.flickr.com/96/232649808_5fcd350525_o.jpg) of that grade is "Adjusted to Heat and Cold, and in all Six Positions." A lesser example is the model 92 Appleton, Tracy & Co., which simply marked "Adjusted." A February 1902 Waltham Ad (http://static.flickr.com/22/26996735_0353e00848_o.jpg) describes it to be only adjusted to three positions. When the Appleton, Tracy & Co. Premier grade was introduced a few months later, it too was only marked "Adjusted," but an October 1902 Waltham Ad (http://img.villagephotos.com/p/2006-9/1217458/1902_Oct_1_ATCo_Premier_LR.jpg) states that it was adjusted to five positions.

Adjustment to Isochronism
Then, there is adjustment to isochronism. This is accomplished by the design and adjustment of the hairspring (the spring coiled inside of the balance wheel). The power output of the mainspring (the spring that is wound when winding a watch) tends to decrease as it unwinds over the course of the day. This causes the balance wheel to rotate through a greater rotational angle when the mainspring is just wound and a lesser angle when the mainspring needs winding. A watch adjusted to isochronism oscillates the balance wheel at the same rate throughout the specified length of run between windings of the mainspring, regardless of how far in each direction the balance wheel rotates. This length of run is typically 30 hours for earlier watches and 42 hours for post World War I watches of better quality. However, mainsprings whose power output were nearly constant over the first 20 hours after a full winding were supplied in higher grade watches starting in the late 1920's. The need for adjustment to isochronism lessened with the application of these mainsprings.

Adjusted Extra or Adjusted Special
Extra and special, as in "Adjusted Extra" or "Adjusted Special" means whatever the manufacturer said it meant at the time that the watch was built. Its only infrequently that we know what that means today.

Like many of our other systems of measurement, American pocket watch movement and case sizes can be traced back to an English system, one known as the Lancashire gage. In this system, the size is based upon the diameter of the watch plate to which the dial is fastened, known as the pillar plate. 0-size has a pillar plate diameter of 1-5/30" (yeah, right!). Nominal sizes then increment by 1/30" for each count. Although there are exceptions, most American pocket watches, and Swiss pocket watches made for the North American market, are sized to even numbers with the most common being 0, 6, 12, 16 and 18. These account for the vast majority of American-made watches. A 6-size watch has a pillar plate diameter of 1-5/30" plus 6/30", or 1-11/30". The diameter of a 16-size movement's pillar plate is 1-21/30", and an 18-size watch is one whose pillar plate diameter is 1-23/30" ( 1-5/30" plus 16/30" and 18/30" respectively). For sizes below 0-size (written x/0), the 1/30” is subtracted from the 1-5/30. Thus a 6/0-size watch has a pillar plate diameter of 29/30”. This is right up there with 12 inches to a foot, 16 ounces to a pound and 32 ounces to a quart. The same people have brought us the term hundredweight, which isn’t a hundred of anything but it is equal to 8 stone. Since a stone is equal to 14 pounds, a hundredweight is equal to 112 pounds.

The fact that even sizes are almost always used, alleviating the necessity of making very fine distinctions, makes it easy to express the watch size with a fairly close approximation. First, measure the diameter of the dial to the nearest 1/32 of an inch, then subtract 1/32" and then subtract 1-5/32". For example, the dial diameter of a 16-size watch is 1-22/32". Subtracting 1/32", we get 1-21/32". Subtracting 1-5/32" leaves 16/32", Hence, its a 16-size watch. Remember to be careful of the hands when measuring the dial diameter. In order to measure the dial diameter, and only the dial diameter, don’t include any part of the case. The bezel, the metal ring that holds the crystal (glass), will have to be removed or opened. In the manner similar to the backs of watches, the bezel either hinges, snaps or unscrews open on an open-face watch and snaps off on a hunting-case watch. Refer to the essay on Opening Cases (https://home.comcast.net/~k_singer/Opening_Pocket_Watch_Cases__k.htm).

Also see What Size Is My Watch? (http://barrygoldberg.net/watchguide/size.htm) on Barry Goldberg’s website.

Good luck,