I have two model 21s. The first is numbered N2604 on the dial and upper plate. The second is numbered 2E11189 on the dial, both plates and both boxes. Why the different numbering system?
Re: Hamilton 21 numbers I've had reason to wonder the same thing. Mine is marked N6125 on the dial, and 2E6125 on the movement. The N is usually in a circle, and I understand that stands for NAVAL OBSERVATORY. Than N I have never seen on a movement.
Re: Hamilton 21 numbers I have been taking the easy route sitting and waiting for someone to answer this question. Well since no one wants to take a shot maybe I have a plausable answer. In checking the Hamilton Ledgers on your chronometers mentioned as well as my own could it be be only those Model 21's which were purchased by the U.S. Government and sent for testing at the Naval Observatory have the N and 4 digit number printed on the dial? I referenced a excellent article in the NAWCC Bulletin No.356 June of 2005. This was written by William O.Bennett in 1977(prior to his death in 1994) who was employed by Hamilton in the development of the Model 21. Preformance specifications established by the Observatory required extensive testing which took 30 days to perform.In the artical is pictured a Marine Chronometer Performance Test card which clearly shows that only a 4 digit number listed in the upper right hand corner of the document. Chronometer 2E6125 with the N dial was finished and sold on 9-7-44 to 64-1377 which is preported to be a code number for the U.S.Government. My instrument is 2E5968 with the N dial finished and sold on 9-7-44 to 64-1377.When I checked on the 2eE1189 chronometer it was finished and sold on 11-26-45 and sold to a John B.Machado # 36923. Ok, perhaps this isn't a sufficient number of examples to form a conclusion but maybe it's a good start. The ledgers only list Hamilton's 2EXXX number so to continue this research individuals who own these chronometers could look up and report what they discover. Maybe I'm all wet with my theory but at least I tried.
Re: Hamilton 21 numbers We have three Hamilton chronometers in the thread. Two were sold to the US government, and they have an abbreviated serial number on the dial as compared to the serial number on the movement. The third one appears to have been sold to a private individual, and the dial and movement numbers match. I wonder if that might be a clue. That third one has the serial number on the movement and the case, matching. I suspect there were more chronometers made than there were cases for them. Look at the US government dispersal sale a few years ago, when numerous chronometers without cases were de-classified, and sold off. I suspect that when a chronometer was due for service, a fresh one was installed in the case while the original went for servicing. Thereby, I suspect serial numbers on boxes were either removed, or perhaps often never put on. I have serviced numerous XXIs over the years. And to my recollection, every one except mine has had the dial and movement serial numbers matching. Does anyone know, really?
Re: Hamilton 21 numbers Hamilton made the model 21, 121 and 221 as three distinct models. The model 21 have numbers 2E001 to 2E12300. The model 121 has a black 24 hour dial 3E001 to 3E040. The 221 has the 4 orbit dial with calendar 4E001 to 4E015. These numbers may not be complete since the records stop in the 50's. They also made variants of the model 21 with various break circuits. I gave one two my daughter as a present for her new husband in July. It has 3 make/break detents in addition to the time. The under dial detent trips once an hour while the other two can be set to trip every minute at a differential time. That allows each of a set of chronometers to have its own difference so the time traces can be distinct. This example is one of 5 made for Cal Tech for their seismic studies.
Re: Hamilton 21 numbers I would never take advice or the personal opinion from a person who doesn't know his left from his right. The chronometer number is on the LEFT upper corner of the card!
Re: Hamilton 21 numbers Burt, I believe you have the answer. The Library has the ledger book on these and you can look them up.They also have a box of the rating cards for each one as tested. From memory I believe that some of the Sold To, names in that column are regular names and some are numbers as you have posted. The numbers represent government or civilian contracts instead of names. The same is true for most of the Military watches, 992B,2974B,4992B, 3992B, Model 23. My personal M21 has N6624 on the dial and 2E6624 on the top plate. I have proof that it was a government contract, because I have the shipping container with matching numbers and it went to a Fast Frigate (Destroyer) the USS Albert David, FF1050
Re: Hamilton 21 numbers I was confused by the reference tio the ledger and the numbers available. I think all the chronometers up to the end of the records are included. Here are the pages for the 24 hour and 4 orbit models. These pages are in the Hamilton on-line database and can be searched by serial number if you are an NAWCC member. Consider these pages a gift from the people who developed the database. Note: Entering 3E001 in the serial number fields will retrieve the summary information for the Model #121 and a link to this image in pdf format. All other alphanumeric serial numbers are entered the same way.
Re: Hamilton 21 numbers Jim, You are very fortunate to have the entire story on your Model 21 Chronometer. It answers all the questions not only about the individual instrument but also another that the 21's only went to the largest ships. Tom, The entire data base Is a much appreciated gift.
Re: Hamilton 21 numbers Doug: I was wrong about the numbers on N2607. I can't see the number on the upper plate because of the balance blocking mechanism. The lower plate is marked 2E2607.
Re: Hamilton 21 numbers While browsing through "MANUAL FOR REPAIR AND HANDLING OF HAMILTON SHIP CHRONOMETER WITH PARTS CATALOG" Contract N8ss-2270 Bureau of Ships Navy Department October 1948 (M. Trauring reprint), I found some notes on the allotment of the Hamilton ship chronometers to Navy ships: "Capital ships of the U.S. Navy (battleships, carriers, cruisers) are allotted two or more of these chronometers. Thus, the navigator can compare readings for more accurate determination of time and longitude. For safety, the chronometers are located in different stations aboard ship, according to the discretion of the ship's Commanding Officer." "Fighting ships other than capital ships (destroyers through submarines) and seagoing ships (such as supply ships, tenders and hospital ships) are allotted one or more chronometers and one or more gimbal chronometer watches. Usage is similar to that on capital ships. For the exact navigating timepiece allowance on a particular type of vessel, reference should be made to the latest timepiece allowance list." This is all pretty far from my main area of interest (railroad watches) so I can't add anything to what is in the manual. Just keep in mind that all that was applicable over sixty years ago; I don't even know if any ships carry chronometers these days! Maybe someone with more contemporary knowledge can add something. By the way, the manual states that "Serial numbers as assigned by the U.S. Navy are engraved on each chronometer dial and the barrel bridge." I believe those are the numbers preceded by the N in a circle. The other numbers, with the 2E (not posted), 3E and 4E prefixes, as shown in the records posted by Tom (post #8 above) are clearly the factory serial numbers. I hope this is of some help. Larry Treiman
I have looked up my mod. 21 serial number, which is 2E6890, with the similar marking on the dial ("N" in a circle and 6890). Nothing unusual though. The ledger notes 64-1578 as buyer on 10-26-44. Could anyone explain who that may be? I guess it's the government as well, but is there a key to those buyer codes (like 64-1618 which appears very frequently)? Thanks ever so much, Rudolf
(F.W.I.W. ) How they, the United States Government, did purchases of chronometers in the 1940'S I cannot definitely say. The Hamilton ledgers are full of sales information to the 64-XXXX designations. This I believe has been accepted by the collecting community as "Government military contracts" without specific information "to whom" in the government it was ordered or received . This specific part of the puzzle is still waiting to be discovered. I can say with some certainty that in earlier times (WWI and earlier) the United States Naval Observatory made all purchases of Chronometer instruments of all types for the United States Government military services. I have viewed about a dozen of the actual chronometer records which were keep at the N.O. and all are specific that the N.O. made the purchases directly from chronometer manufactures and have other specific information as to dates accepted/purchased and manufactured , price paid and trial numbers. Of course they also contain the complete record of chronometer service. I have viewed a single Negus instrument records which indicated it was purchased by the N.O. in 1868 for $400.00 and after some military service was sold to the "Coast Survey" in March 1888 for $266.25. While this is a single example it's possible that sale indicates either that organization was not a military unit per-say or that perhaps some non-military units were not under the observatory purchase/ maintenance program? That of course brings up the question of then how were those specific chronometers serviced, tested and recycled? If I had to take a guess I would conclude nothing changed in the purchase process during WWII and all chronometers were purchased by and went directly to the observatory for dissemination to the various military units for service. Just a side note of interest during the 1940's, no doubt because of electronic timing instruments, chronometer trials were reduced to 30 days as to the earlier standard of 6 months trials when done by clock comparison. I think it very exciting and interesting that even after studying for many years we still have the opportunity to find more and more about these instruments to satisfy our appetite of information about these remarkable timekeepers.
In 1888 the United States Coast and geographic Survey was a "civilian" organization under the United States Department of Commerce. This organization founded in 1807 ,known by 3 others names during its tenure, was responsible for various responsibilities including "mapping and charting" for our government until being closed in 1970. Once again my opinion is that all 64-XXXX sold by Hamilton codes indicate the instrument was headed for the U.S.N.O. and for military use. As we continue to stumble upon new information perhaps in the near future we will uncover those more specific answers.
Glorious! Thank you very much for the quick answer and the detailed explanation. I knew it would be hard to decipher these codes.
In "my just a side note" comment I stated the U.S.N.O. during the 1940's reduced their testing to 30 days instead of the 6 month period in the early years should actually read 35 days. It was Hamilton, at their factory, who tested their chronometers for 30 days prior to shipping out to the N.O. where they began their trials. Sorry for the typo as I did have the correct information at hand.
