December 25, 2005, 21:20
Fred R. HoughamHAMILTON MODEL 121 ARMY/AIR FORCE CHRONOMETERS
HAMILTON MODEL 121 AIR FORCE 24 HOUR CHRONOMETERS
The following account of these chronometers was put together from the original Hamilton records, internal memos, and copies of various letters to and from the companies involved.
Sometime in late 1941 or early 1942 (the exact date is unknown) the U.S. Army Air Force contacted the Hamilton Watch Company and requested that they supply the Army Air Force with chronometers to be used as a master time source.
The chronometers were to be configured with black 24 hour dials with white hands and white numerals and were to be mounted in individual chronometer boxes with gimbals, similar to the existing Model 21’s, with three individual chronometers mounted in a vibration free wood carrying case.
Contract number W535-AC-29502 was received and Hamilton spent most of 1942 working on the final specs and assembling the necessary parts. The original specifications called for the dial to be inscribed U.S. Army Air Corps and the 3 units carrying case identification plate to be inscribed as Master Time Source. In a letter dated July 25, 1942, the Material Division, Army Air Force, Wright Field, requested, without explanation, that the dial be changed to read U.S. Army Air Force and the carrying case identification plate be changed to read Chronometer Unit.
Hamilton designated the units to be Model # 121 starting with serial number 3E 001. As per the specifications the serial number was to be applied to the dial, the pillar plate, the barrel bridge, and the front of the gimbaled mounting box. The carrying case indentification plate was to be numbered starting with number 42-1.
Three each of the chronometers were to be placed in a carrying case with vibration damping mountings. Hamilton started work on the chronometers in late 1942, using the existing 14 Jewel Model 21’s and converting them to the 24 hour dial configuration.
These units were designated as Model 121, part number 42221, and using dial # 42236.
Hamilton outsourced some of the parts needed, most notably to the National Lock Co., Rockford, Ill, for the box hardware, the Lord Manufacturing Co, Erie, Penn., for the vibration suspension mountings, and to the Seth Thomas Clock Co., for the chronometer boxes and the 3 unit carrying case. The first 3 unit set was delivered to the Army Air Force at Wright Field, Dayton Ohio, on March 4, 1943. The original contract called for a total of 9 three unit sets, but the last three sets were cancelled on August 19, 1943, ( for reasons unknown), so only a total of 6 three unit sets were built.
The only 3 unit set known to have survived intact is serial number 42-3, holding chronometers number 3E 007, 3E 008 & 3E 009.
The enclosed 1943 memo indicates when the deliveries were made to the Army Air Force:
Contract……….. 1943 - Account with Model 121
W-535………… FINANCE OFFICER ( 3 ) - 85 si
AC-29502……… Wright Field 14 J Air Force
Purchase order.. Dayton, 0. Chronometers
# 42-20399-P….. Terms: 30 days net
…………………..
Invoice No…….. 3-4-7520…………1-—-Air-Force Chronometer Unit …………………$1,500.00
………………………..Model #121 Dial # 42236
…………………………………………….Delivered to
………………………………..Capt. Jno. C. Goodell
………………………………………….of Wright Field
………………………………….on train enroute from
…………………………Phila. to Dayton, Train #31
……………………………………….At Lancaster Pa,
……………………………………(Unit No. A.F. 42-1)
……………………consisting of (3 # 85 si. Models
…………………………# 3E 001 - 3E 002 - 3E 003
Invoice No…….. 3/10-7651………….1—Air-Force Chronometer Unit …………………$1,500.00
……………………………………………Model # 121
……………………………………Delvd personally to
……………………………………Lt. P. W. Johnston
…………………………………………at Wright Field
………………………………by Messrs M.F. Manby
………………………………………..& L.F, Halligan
……………………………………..(Unit No.A.F.42-2)
…………………..Serial # 3E 004 - 3E 005 - 3E 006
Invoice No……... 4/8-8728…………1-—Air-Force Chronometer Unit $1,500.00
…………………………………………….Model #121
………………………………….(Unit No. A.F. 42-3)
……….………..Serial Nos. 3E 007 3E 008 3E 009
…………………………………Delvd by Mr. Halligan
…………………………………to, Lt. P.W. Johnston, ……………………………………………Wright Field
Invoice No…… 5/19-1975………….1---Air-Force Chronometer Unit $1,500.00
………………….. Model # 121………………. 42236……………
…………………. ………………………………..…(Unit No. A.F. 42-4)
…………………. ……………..…Serial Nos. - 3E 010 3E 011 3E 012
…………………..
…………………..
………………….. ………………………………Delvd by Mr. Halligan to
………………….. ……………………………………….P.W.Johnston at
………………….. …………………………………………….Wright Field
…………………..
Invoice No…… 6/17-10730………1---Alr-Force Chronometer Unit $1,500.00
…………………. ………….Model #121………… 42236 ………..
…………………. ………………………….……….(Unit No. A.F. 42-5)
…………………. ………………….Serial Nos. 3E 013 3E 014 3E 015
………………….
………………….
………………….. …………………………..Delvd to Lt. P.W. Johnston
…………………. …………………………………………at Wrlght Field
………………….. ………………………………………by Mr. Halligan
………………….
………………….
………………….
………………….
………………….
………………….
………………….
Contract………. ……………. l——AIR-Force Chronometer Unit….. …….. ……..Model 121
W-535………… …………. Model #l21………………………... …………..(3)-85 size-14
AC-29502…….. ……………………………(Unit No. A.F. 42-6) …………. AIR-FORCE
Purchase Order …………..Serial Nos. 3E 016 3E 017 3E 018 ……CHRONOMETER
#42-20399-P…. ………………___UNIT
………Terms:Net 30 day
…..Invoice #….. …………………………Delvd by Mr. Halligan …………$ 1500.00
7/25-10959…… ………………………….to Lt. P.W. Johnston …………………………….
…………………………………at Wright Field …………………………….
…………………………….
…………………………….
…………………………….
…………………………….
………………… Model # 121 is composed of 3 # 85 si Chrono …………………………….
…………………. Each Chrono consists of the following; …………………………….
…………………. Movt - Model 121 - Part 42221 …………………………….
…………………. Case and Gimbal Assembly - Part- 42100 …………………………….
…………………. Case Suspension - Part 42235 …………………………….
…………………. Box Mounting - Part 42222 …………………………….
…………………. Dial - # 42236 …………………………….
…………………. Inspected and approved by Army Air Force Resident Inspector, …………………………….
…………………. Movement - 85 size -. l4jewel - Model 121 - Part 42243 …………………………….
…………………. Hand - Hour - 42237 …………………………….
…………………. Min - 42238 …………………………….
…………………. Sec. - 42239 …………………………….
…………………. Wind Indicator - 42243 …………………………….
…………………. Serial number of movement assigned by Hamilton is to be …………………………….
…………………. engraved on pillar plate, barrel bridge, .face of dial ……………………………
…………………. and front of mounting box. …………………………….
…………………. Serial number of Chronometer Unit assigned by A.A.F. to …………………………….
…………………. be engraved on name plate fastened to front of Susoension …………………………….
…………………. Case - Serial numbers from A.F. 42-1 to A.F. 42-.9 inclusive. …………………………….
…………………. Inspection - At Contractor's Plant. …………………………….
After the Army Air Force cancelled the chronometer order Hamilton continued to build the 24 hour version of the Model 21, building a total of 42 units, although no information exists for 3E 041 and 3E 042.
Only units 3E 001 thru 3E 018 ( and possibly units 3E 022 & 3E 023) have the Army Air Force dial. The remaining 22 units have a black 24 hour dial, part number 42253, simply marked Hamilton Watch Co. These units, for the most part, were sold to three west coast instrument companies: Northwest Instrument, Seattle Wa, and the George E.Butler Co. & The Louis Weule Co., both from San Francisco, Ca.
.SERIAL #.. .COMPLETED …DATE SOLD… …ORDER #… ………..PURCHASER………….
3E 001……. 3/4/1943……... 3/4/1943………. 64-7520…….. U.S. ARMY AIR FORCE
3E 002……. 3/4/1943……… 3/4/1943………. 64/7520…….. U.S. ARMY AIR FORCE
3E 003……. 3/4/1943……… 3/4/1943………. 64/7520…….. U.S. ARMY AIR FORCE
3E 004……. 3/10/1943…….. 3/10/1943……… 64-7657…….. U.S. ARMY AIR FORCE
3E 005……. 3/10/1943….... 3/10/1943……… 64-7657…….. U.S. ARMY AIR FORCE
3E 006……. 3/10/1943……. 3/10/1943……… 64-7657…….. U.S. ARMY AIR FORCE
3E 007……. 4/8/1943…….. 4/8/1943………. 64-8728…….. U.S. ARMY AIR FORCE
3E 008……. 4/8/1943…….. 4/8/1943………. 64-8728…….. U.S. ARMY AIR FORCE
3E 009……. 4/8/1943…….. 4/8/1943………. 64-8728…….. U.S. ARMY AIR FORCE
3E 010……. 5/19/1943…… 5/19/1943…….. 64-9775…….. U.S. ARMY AIR FORCE
3E 011……. 5/19/1943…… 5/19/1943…….. 64-9775…….. U.S. ARMY AIR FORCE
3E 012……. 5/19/1943…… 5/19/1943…….. 64-9775…….. U.S. ARMY AIR FORCE
3E 013……. 6/17/1943…… 6/17/1943…….. 64-10730……. U.S. ARMY AIR FORCE
3E 014……. 6/17/1943…… 6/17/1943…….. 64-10730……. U.S. ARMY AIR FORCE
3E 015……. 6/17/1943…… 6/17/1943…….. 64-10730……. U.S. ARMY AIR FORCE
3E 016……. 7/15/1943…… 7/15/1943…….. 64-10959……. U.S. ARMY AIR FORCE
3E 017……. 7/15/1943…… 7/15/1943…….. 64-10959……. U.S. ARMY AIR FORCE
3E 018……. 7/15/1943…… 7/15/1943…….. 64-10959……. U.S. ARMY AIR FORCE
3E 019……. 2/8/1946……. 3/13/1947…….. 38024………. GEORGE E. BUTLER CO.
3E 020……. 7/13/1944…… 7/23/1946…….. 28429………. GRAVES STEWWER CO.
3E 021……. 6/27/1946…… 6/27/1946…….. 27998………. GEORGE E. BUTLER CO.
3E 022……. 10/9/1944……. 10/9/1944……… 64-17354……. U.S. ARMY AIR FORCE
3E 023……. 10/9/1944……. 10/9/1944……… 64-17354……. U.S. ARMY AIR FORCE
3E 024……. 11/17/1944…… 11/17/1944……. 17828………. NORTHWEST INSTRUMENT
3E 025……. 8/15/1944…… 8/15/1944……… 16691………. NORTHWEST INSTRUMENT
3E 026……. 11/2/1944…….. 11/2/1944……… 17684………. NORTHWEST INSTRUMENT
3E 027……. 11/17/1944…… 11/17/1944…… 17828………. NORTHWEST INSTRUMENT
3E 028……. 6/5/1946……. 6/5/1946……… 25765………. LOUIS WEULE CO.
3E 029……. 7/2/1945…….
3E 030……. 6/21/1946…… 6/21/1946…….. 27646………. GEORGE E. BUTLER CO.
3E 031……. 7/25/1946…… 7/25/1946…….. 28545………. LOUIS WEULE CO.
3E 032……. 7/25/1946…… 7/25/1946…….. 28545………. LOUIS WEULE CO.
3E 033……. 2/5/1946……. 8/7/1946……… 28659………. GEORGE E. BUTLER CO.
3E 034……. 8/30/1946…… 4/15/1947…….. 39484………. GEORGE E. BUTLER CO.
3E 035……. 9/17/1946…… 9/17/1946……. 30083………. GEORGE E. BUTLER CO.
3E 036……. 9/17/1946…… 9/17/1946……. 30083………. GEORGE E. BUTLER CO.
3E 037……. 9/25/1946…… 9/25/1946……. 30227………. GEORGE E. BUTLER CO.
3E 038……. 1/9/1947……… 1/9/1947………. 36596………. GEORGE E. BUTLER CO.
3E 039……. 2/19/1946…… 2/19/1946…….. 23356………. KARL PLEPLA
3E 040……. 1/3/1947……… 1/3/1947………. 31244………. LOUIS WEULE CO.
3E 041…….
3E 042…….
The following notes include what is currently known about the surviving units.
In the status column a ( pc ) indicates the chronometer is in a private collection.
( u ) indicates current status in unknown.
….SERIAL #…. ………………………NOTES……………………………….. ..STATUS..
3E 001…….. …………………………………………………………………… …..U…..
3E 002…….. ……………………………………………………………………. …..U…..
3E 003…….. …….CONV. TO 12 HOUR DIAL BY HAM.6/2/54……….. .…..P C…..
………( PROBABLY DUE TO LACK OF PARTS)……….
3E 004…….. …………………………………………………………………… …..U…..
3E 005…….. …………………………………………………………………… …..U…..
3E 006…….. …………………………………………………………………… …..P C…..
……………………………………………………………………
3E 007…….. …………ONLY COMPLETE 3 BOX SET………………... …..P C…..
3E 008…….. ……KNOWN TO………. …..P C…..
3E 009…….. …….….HAVE SURVIVED………. …..P C…..
……………………………………………………………………
3E 010…….. ……………….DIAL MARKED 3E 006………. …..P C…..
3E 011…….. …………………………………………………………………… …..U…..
3E 012…….. …………………………………………………………………… …..U…..
……………………………………………………………………
3E 013…….. …………………………………………………………………… …..P C….
3E 014…….. …………………………………………………………………… …..U…..
3E 015…….. …………………………………………………………………… …..U…..
……………………………………………………………………
3E 016…….. …………DIAL MARKED 16 MOVEMENT # 12485………. …..PC…..
3E 017…….. …………………………………………………………………… …..U…..
3E 018…….. …………………………………………………………………… …..U…..
……………………………………………………………………
3E 019…….. …………………………………………………………………… …..U…..
3E 020…….. ……..MEMO INDICATES UNIT WAS DONATED………. …..U…..
3E 021…….. …………………………………………………………………… …..U…..
3E 022…….. …….3E 022 & 3E 023 MOST LIKELY SOLD TO………. …..U…..
3E 023…….. …….AIR FORCE AS SPARES / SPARE PARTS………. …..U…..
3E 024…….. …………………………………………………………………… …..U…..
3E 025…….. …………………………………………………………………… …..U…..
3E 026…….. …………………………………………………………………… …..U…..
3E 027…….. ………………………………………………………………….. …..U…..
3E 028…….. …………………………………………………………………… …..U…..
3E 029…….. MARKED G.C.T. ON DIAL & WAS BREAK CIRCUIT…… …..P C…..
3E 030…….. …………………………………………………………………… …..U…..
3E 031…….. …………………………………………………………………… …..U…..
3E 032…….. …….MARKED PROPERTY US ARMY ON DIAL………. …..P C…..
3E 033…….. …………………………………………………………………… …..U…..
3E 034…….. …………………………………………………………………… …..U…..
3E 035…….. …………………………………………………………………… …..U…..
3E 036…….. …………………………………………………………………… …..U…..
3E 037…….. …………………………………………………………………… …..U…..
3E 038…….. …………………………………………………………………… …..U…..
3E 039…….. …………………………………………………………………… …..U…..
3E 040…….. …………………………………………………………………… …..U…..
3E 041…….. …………NO INFORMATION ON 3E 041 & 3E 042………..
3E 042…….. ……………….IS CURRENTLY AVAILABLE………..
Hamilton also made a 2nd run of 24 hour movements. These movements are marked 2E on the dial and movement and are in the narrow serial number range of 2E 12215 thru 2E 12240.
Its not known if all 25 units were built because records only exist for the following:
The two units indicated might currently be at the NAWCC Museum
2E 12215-PC
2E 12218
2E 12227
2E 12229-box only at the NAWCC Museum ??
2E 12230
2E 12232
2E 12233-NAWCC Museum movement & dial marked 2E12233 box marked 2E12229 ?
2E 12238
2E 12239
2E12240
Any information as to the whereabouts of any of the unknown 3E or 2E 24 hour units would be greatly appreciated.
Regards
Fred Hougham