Loading…
Enter the serial number from the pocket watch movement below. Do not use the case number. Tips for looking up your watch

How to Find Info About Your Pocket Watch

The Pocket Watch Database has compiled data covering the major American pocket watch manufacturers and created an easy way to find information using the serial number on the watch movement. Here are a few tips to find information about your pocket watch:

  1. Always input the serial number from the pocket watch movement (the "guts" of the watch).
  2. Never use the serial number from the case or any other part.
  3. If the serial number includes a letter, enter it along with the number when using the lookup feature.
  4. Many pocket watch case backs screw off. Others may require a dull wide blade to pry or pop the cover. Be careful not to scratch or damage the movement.
  5. Always select the correct manufacturer, which is usually stamped on the watch movement.
  6. If the manufacturer is not listed on the site, you may have a "private label" watch or it may not be American-made.
  7. Understand that many companies did not keep accurate or complete records. As a result, information displayed on this site may have inaccuracies. This is to be expected, and we have included an option to report inaccurate information on the result pages so the database can be continually improved.
Pocket Watch Serial Number Lookup - Hamilton, South Bend, Illinois, Rockford, Waltham & Elgin Pocket Watches
  Serial Number:
Need to replace a watch crystal? Use our new crystal size guide to find the proper fit.

Pocket Watch Movement Adjustments

Movement adjustments were conducted at the factory to improve the precision and accuracy of timekeeping.


Due to the intrinsic properties of the materials and the variant forces applied to the mechanics by gravity, watch movements naturally deviate from accurate timekeeping when introduced to variances of temperature and position. Adjustments are conducted to precisely average these deviations to maintain a consistent rate of oscillation, resulting in accurate timekeeping.

Proper adjustments were extremely important for watches designed for railroad service. Due to intricate train schedules, errors in timekeeping were very dangerous. Once railroad standards were adopted, watches used in service were required to be keep accurate time within 30 seconds per week.

Prior to 1908, it was common for manufacturers to simply stamp adjusted movements as “Adjusted” without indicating the specific adjustments applied. This usually indicated the watch was adjusted to temperature and 3 positions. However, in some cases, this actually meant 5 or 6 positions. Once more stringent railroad requirements were implemented in 1908, manufacturers began stamping movements to specify the adjustments.

It is important to note that there was no standardization for adjustment qualifications between manufacturers or even grades produced by the same company. A movement requiring 3 adjustments might qualify within an 8-second variance for one manufacturer and a 15-second variance for another.

Adjusted watches usually sold for a premium due to the extra time and skill required for the adjustments to be conducted at the factory.

Unadjusted

Unadjusted movements have been manufactured with no effort spent to adjust the watch to temperature or positional variations. Even unadjusted, these watches of lower quality were still expected to keep accurate time within a few minutes per day.

Adjusted to Temperature (or Heat & Cold)

Temperature adjustment was a lengthy process, usually conducted over the span of several days. Movements were carefully timed in climate-controlled boxes of both temperature extremes, 40 degrees for cold and 90 degree for heat. Rate cards containing time logs for each movement were then analyzed, and screws on the balance were adjusted accordingly by a skilled worker. The screws help compensate for the expansion and contraction in the metal balance wheel in different temperatures, averaging the timing differences between both extremes.

Adjusted to Isochronism

Isochronism adjustments were conducted to maintain a uniform performance while the mainspring gradually loses power from wind-up to wind-down. This was achieved by modifying the pinning and vibration of the hairspring, attempting to equalize the rotation angles of the balance wheel regardless of the strength of power remaining in the mainspring.

Adjusted to Positions

Position adjustments attempt to average the timing errors between positions for more precise timekeeping. Deviations in positional rates are caused by frictional and poise errors, which are more prevalent in the vertical positions. Depending on the qualifications for the grade determined by the manufacturer, the watch would be timed and adjusted using the following positions.


3 Positions

  • Dial Up
  • Dial Down
  • Pendant Up
  • (Also Adjusted to Temperature)

Pictured: A movement adjusted to temperature and 3 positions.

4 Positions

  • Dial Up
  • Pendant Up
  • Pendant Right
  • Pendant Left
  • (Also Adjusted to Temperature)


5 Positions

  • Dial Up
  • Dial Down
  • Pendant Up
  • Pendant Right
  • Pendant Left
  • (Also Adjusted to Temperature)

Pictured: A movement adjusted to temperature, isochronism, and 5 positions.

6 Positions

  • Dial Up
  • Dial Down
  • Pendant Up
  • Pendant Right
  • Pendant Left
  • Pendant Down
  • (Also Adjusted to Temperature)

Pictured: A movement adjusted to temperature and 6 positions.

Total Number of Adjustments

Some manufacturers eventually began marking movements according to the total number of adjustments. Eight or Nine total adjustments should not be confused with being adjusted to eight or nine positions.


8 Adjustments

  • Temperature (Or Heat, Cold)
  • Isochronism
  • 6 Positions (Or 5 Positions if Temperature is Qualified as 2 Adjustments)
Pictured: A movement indicating 8 adjustments.


9 Adjustments

  • Heat
  • Cold
  • Isochronism
  • 6 Positions
Pictured: A movement indicating 9 adjustments.