Automatic K-400 cld
1954 · 10K yellow GF · Automatic
About the Automatic K-400 cld
Made only in 1954, the Automatic K-400 cld is a round automatic in a 10K yellow gold-filled case with a stainless steel back. It runs on Hamilton's caliber 661, a 17-jewel automatic with sweep seconds. The cld suffix indicated a sealed case: the crystal was set into the bezel on a gasket, the bezel seated against the case with a second gasket, and the crown used a two-piece stem with its own gasket at the stem tube — keeping the movement well-shielded from moisture and dirt. This wasn't a waterproof designation; Hamilton's waterproof marketing push came later in the decade. The K-400 belongs to Hamilton's early domestic automatic lineup, a family that was still establishing itself in the American market during the mid-1950s.
Surviving examples vary quite a bit in how the dial has held up. The embossed gold numerals at 3, 6, 9, and 12, paired with embossed gold luminous markers, give the dial a textured quality that reads well even on aged examples, but the luminous material in the markers can discolor or flake over seven decades. The gold-filled case tends to show wear on the high points of the lugs, so check those areas carefully before buying.
From the Catalog
Hamilton listed the K-400 with sweep seconds, embossed numerals, and luminous markers, and promoted it as water resistant, shock resistant, and anti-magnetic. It retailed for $85.00 in 1954 on a leather strap.
Hamilton Catalog Images
1954
What to Look For
| Dial | Look closely at the luminous markers. The lume can discolor, crack, or flake at this age, which is common but affects appearance. The embossed numerals and markers themselves are relatively durable, but check for any lifting or loss around the edges. |
| Crystal | This case opens through the crystal rather than the case back. Look for scratches or pry marks around the bezel edge, which are a telltale sign of someone attempting to open it the wrong way. A replacement crystal is fine, but bezel damage is harder to fix. |
| Movement | A stored caliber 661 can accumulate enough friction from dried lubricants to stop entirely. A watch that only runs when shaken, or stalls after a few hours on the wrist, needs a service before regular wear. |
| Case | Gold-filled cases from this era show wear first on the lug tips and case flanks. Light wear is expected and honest, but check for any areas where the gold layer has worn through to the base metal, which affects long-term durability. |
| Crown | The crown should pull out cleanly and set the time without resistance or slipping. A rough or spongy feel can indicate worn keyless works. Also confirm it's an original period crown, as replacements are common. |
The Movement
The caliber 661 is a 17-jewel automatic movement made by Hamilton in the United States. It winds through a rotating oscillating weight as the watch moves on the wrist, so no manual winding is needed during regular wear. The 661 is a solid performer from this period, though like any movement that's been sitting for years, it benefits noticeably from a proper service with fresh lubricants.