Automatic K-504
1955–1956 · Stainless Steel · Automatic
About the Automatic K-504
Made from 1955 through 1956, the Automatic K-504 is part of Hamilton's Automatic family, the broader line of self-winding models Hamilton developed through the 1950s. It runs on the caliber 661, a 17-jewel automatic movement, and comes in a stainless steel round case with a sweep seconds hand. Hamilton offered this model in two dial configurations: embossed silver numerals with luminous dots, or embossed silver numerals with markers and luminous dots, giving buyers a bit of choice between a busier and a cleaner look.
Embossed dials age differently than printed ones, and on the K-504, the raised numerals and markers tend to hold up well over time, though the white dial surface can show yellowing or spotting on unserviced examples that spent decades in less-than-ideal storage. Both dial variants turn up with some regularity, so finding one is not difficult, but finding a clean example with the lume dots still intact and the dial free of damage takes more patience.
From the Catalog
Hamilton described the K-504 in 1955 as a stainless steel, sweep seconds automatic with shock resistance, anti-magnetic protection, and waterproof construction. Depending on dial configuration and whether it was paired with a bracelet or strap, original retail pricing ranged from $75.00 to $87.50.
Hamilton Catalog Images
1955
1956
What to Look For
| Dial | Look closely at the embossed numerals and markers. The raised construction holds detail well, but the white dial surface can yellow or develop spotting over time. Check the luminous dots carefully. Old lume can crack, flake, or go missing entirely, which is a cosmetic issue worth factoring into your assessment. |
| Crystal | This case opens through the crystal rather than through the case back, so look for scratches or pry marks around the crystal edge. Attempts to open the case back instead of the crystal are common and can leave visible damage. |
| Movement | Ask about service history. The caliber 661 is an automatic, and oil that has thickened and dried over decades of sitting can build up enough friction to stop the movement entirely. A watch that runs one day and stops the next, or winds manually but struggles to wind automatically, is likely overdue for a service. |
| Case | Stainless steel holds up well, but check the lugs for wear and the case edges for dings from daily use. Also confirm the watch has not been submerged. Hamilton marketed this model as waterproof at the time, but vintage gaskets have long since degraded and no vintage watch should be trusted near water without a full re-seal. |
| Crown | Check that the crown screws down or seats properly and that the stem engages cleanly at each position. A loose or sticky crown often points to a worn stem or a crown that has been replaced with a non-original part. |
The Movement
The caliber 661 is a 17-jewel automatic movement, meaning it winds itself through the motion of the wearer's wrist via an oscillating weight. Hamilton used this movement across several models in the mid-1950s, and it is a reasonably robust caliber when properly serviced. The sweep seconds hand runs from the movement directly, giving the dial a clean, uninterrupted look without a separate subseconds register.