HistoricTimekeepers Restoration Services and Supplies

To see images full size right click and select "view image" or "view image in new tab" Depending on browser




HTI Main Page




Popular Highlights


Notes for Young Watchmakers

HTI Approach to Service

Microscopes in Watchmaking

When only a watchmaker will do

The 37500 Contract Prototype

Restoration of Omega Jump Seconds Clock

Shop Tour

Photo Series Index Page

Warbird Clocks for Sale

Equipment for Sale











Hamilton and Elgin 37500 Elapsed Time Clock




Restored Hamilton Elgin 37500 Aircraft Clock
WWII Hamilton Mod 37500

If you have a 37500 clock you need serviced, you will find  services and charges listed on the Aircraft Clock Restorations and Repair Services page.

The 37500 is one of the most complicated clocks produced for use in aircraft.  It has functions for displaying 24 hour time, running seconds, length of trip (12 hour), 60 minute center seconds chronograph and Civil Date.  It has a large 2 3/4 inch dial opening.  Its production was also complicated with the contract split between Hamilton and Elgin watch companies.  Elgin made the plates, screws and escapement, Hamilton made the other parts.  The parts were then transhipped and each company assembled finished clocks.  They were paid for both parts produced and clocks assembled; poor contract officer!

The 37500 was a replacement for the Jaeger A-10 ordered before the US entered WWII.  The Jaeger product also provides Civil Date and a Time of Trip function and was used in pre-war USAAC and USN aircraft.  But with the entry of the US into the war, military timepieces from Switzerland were no longer available.  All US watch companies were required to turn their production to the needs of the US military and this clock was a high priority.  As far as I know, the production of nearly 28,000 clocks went to the USN Beu. of Aeronautics and was used in TBF, TBY, PBY and a number of carrier based aircraft.  It was kept in service well into 1990s as evidenced by various depot tags that may be affixed to a clock case.  These were even issued to Orion P-3s!

All 37500 clocks sold or serviced  by Historic Timekeepers have new unbreakable mainsprings installed rather than 60 year old carbon mainsprings that are fatigued or rusted and ready to break.  It is the only way we can get good performance.  We are the ONLY facility that has access to these springs!

Also, EVERY 37500 sold by HTI also has an original new/old stock dial and the hands are finished in the original color scheme.   Most of the clock dials were refinished with white markings by the USN in the 1960s and the hands were also painted white.  This change directive was an attempt to comply with no radium policy; however, the dials and hands were not, and are not radioactive.  While some foreign clocks DID use radium, the 37500 did not.

We can provide dials and hand refinishing service to customers during the course of overhauling their 37500 as well.  However, we do not sell parts.

When a 37500 is serviced, it is completely disassembled, individual parts cleaned and inspected, replaced or refinished as needed.  If a 37500 sent in for service needs a new part (balance staff, jewel, mainspring, hand, knob, dial) this will be noted in the quote for service.

Cost of Fully Refurbished 37500 with NOS dial, unbreakable mainsprings, Certificate of Performance and 1 year warranty:  $1100 plus shipping.



For shipping  or ordering information, contact:

Dewey Clark                   410.592.9998

Email Contact:         Historictimekeepers@gmail.com

Site Created and Expanded since 1999!!

(Watch my hair go grey)