Accumatic A-400
1962–1964 · 10k Yellow Gold Filled · Automatic
About the Accumatic A-400
Made from 1962 through 1964, the Accumatic A-400 runs on Hamilton's caliber 689, a 17-jewel automatic movement, and comes in a cushion-shaped 10K yellow Gold Filled case. The dial is silver with applied gold numerals at 12 and applied gold markers elsewhere, and a sweep seconds hand. The A-400 is part of Hamilton's Accumatic family, which was Hamilton's line of automatic wristwatches aimed at the everyday American market during the early 1960s. Retail pricing in 1963 was $79.50 on strap and $89.50 on bracelet.
Applied gold details on a silver dial are among the first things to assess on any example you encounter, since the markers and numerals can loosen or show tarnishing at the edges after decades. The cushion case shape gives the A-400 a little more visual character than the round Accumatics of the same era, and that makes clean, unpolished examples with intact case sharpness genuinely pleasant to find.
From the Catalog
Hamilton's 1963 catalog positioned the A-400 as an accessible automatic in a gold-filled case, priced at $79.50 on strap, and described it plainly without elaborate language, letting the cushion case shape and yellow gold-filled finish do the talking.
Hamilton Catalog Images
1963
1964
What to Look For
| Dial | Check each applied gold numeral and marker closely. Any that are separating, tilting, or missing will be obvious under magnification and are difficult to source correctly. The silver dial finish can also show age spots or discoloration that photographs often hide. |
| Crystal | These left the factory with acrylic crystals. Expect scratching on any unserviced example. A replacement is inexpensive, but confirm the correct diameter before ordering, as cushion cases can be fussier than round ones. |
| Movement | The caliber 689 is an automatic, so it should wind and run from wrist motion. Dried lubricants are the most common reason an otherwise intact 689 runs inconsistently or stops, and a full service will address that. Listen for any irregular ticking or amplitude issues. |
| Case | The 10K yellow gold-filled case can show brassing at lug edges and high contact points after years of wear. Polishing hides wear but also rounds the case lines permanently, so look for examples with honest wear rather than an over-polished surface. Case backs on these can be tight, and forcing one incorrectly risks damage to the back or the case body. |
| Crown | Pull the crown gently to check for smooth winding and easy date-less setting. A crown that slips or feels gritty may indicate a worn or damaged stem, and the two-piece stem design used in these cases requires care during movement removal. |
The Movement
The caliber 689 is a 17-jewel automatic movement built by Hamilton in the United States. It winds from the natural motion of the wrist via a rotor, so there is no need to wind it manually under normal conditions. The 689 is a solid, serviceable movement that rewards clean lubricants and careful adjustment, and it keeps respectable time when properly maintained.