Auto Date Explorer
1975–1977 · 10k YGF
About the Auto Date Explorer
The Auto Date Explorer was Made from 1975 through 1977, offered in a round 10k yellow Gold Filled case with hidden lugs. It belongs to Hamilton's Auto Date family, a line built around automatic movements with date complications. Power comes from the caliber 825, a Hamilton-era Swiss automatic that handles both winding and quick-change date functions.
Finding one in good shape means paying close attention to the case finish, hidden lug designs can mask wear at the lug roots that only shows up under close inspection. The applied indices are also worth scrutinizing, since any that have shifted or come loose will be obvious against the dial. multiple years models don't always turn up in predictable condition, so patience with the search pays off.
From the Catalog
Hamilton listed the Auto Date Explorer in 1975 at $180.00, described simply as a 10k gold filled model on strap. The catalog entry was minimal, letting the case material and price do most of the talking.
Hamilton Catalog Images
1975
What to Look For
| Dial | Look closely at the applied indices. Any that are loose, coming loose, or sitting at an angle should be factored into your assessment, as reattaching them properly requires dial work. Also check for moisture damage or discoloration around the date window. |
| Crystal | Inspect for deep scratches or chips. A heavily scratched crystal usually means the dial underneath has seen some contact too, so don't stop at the surface. |
| Movement | The caliber 825 has a small U-shaped spring that presses on the index lever, and it has a reputation for springing free during service and disappearing entirely. Ask whether the watch has been serviced recently and by someone familiar with this caliber. Dried oil creates enough friction to stop the movement even when the mainspring still has tension, so a watch that winds but won't run reliably needs a service before you trust it. |
| Case | Gold filled cases show their age at the high-contact points first, the caseback edges, the lugs, and anywhere a bracelet or strap hardware has rubbed. Look for brass showing through the gold layer. On hidden lug designs, check where the lugs curve under the case, since wear there is easy to miss at a glance. |
| Crown | Cycle through all crown positions and confirm the date advances cleanly and snaps to position. A crown that slips or a date that jumps erratically points to wear or damage in the quick-change mechanism. Also confirm the crown screws or pushes back in fully and sits flush. |
The Movement
The caliber 825 is a Swiss-made automatic with a quick-change date complication, built during Hamilton's later production era. It winds through a rotor with normal wear and use, and the date advances at midnight via an independent mechanism rather than being driven directly off the hour wheel. It's a serviceable movement when properly maintained, though the date mechanism has a few small components that demand careful hands during a service.