Day 'N Date ST-6501
1972–1973 · 14k Gold Electroplate Day
About the Day 'N Date ST-6501
Made from 1972 through 1973, the Day 'N Date ST-6501 runs on Hamilton's caliber 645 and comes in a round case finished in yellow 14K Gold Electroplate. It belongs to Hamilton's Day 'N Date family, a line built around the combined day and date display that was a popular feature in the early 1970s. The hidden lug design gives the case a clean, integrated look that was very much in step with the styling sensibilities of that era.
Gold Electroplate cases from this period are worth examining closely, since decades of wear can thin the plating at the lugs and crown edges before it shows anywhere else on the case. Finding one with even plating and a clean dial with legible applied indices is the real benchmark here. Two years of production keeps the supply modest, so a well-preserved example is worth taking seriously.
From the Catalog
Hamilton listed the ST-6501 in its catalog as a yellow 14K gold electroplate model with a quick-change day and date display, priced at $100 in 1972 dollars. That price point put it squarely in Hamilton's accessible dress watch range for the period.
Hamilton Catalog Images
1972
1973
What to Look For
| Dial | Look at the applied indices carefully under good light. They should sit flush and even, with no separation from the dial surface, corrosion creeping under the base, or discoloration around the feet. Check that the day and date text is crisp and the printing shows no fading or moisture ghosting. |
| Crystal | Expect a plastic crystal at this age. Minor surface scratches are normal and polishable, but look for deep gouges or crazing, which signal a replacement is needed before the watch goes back on a wrist. |
| Movement | Dried oil is a genuine concern in any automatic that has been sitting unworn for years. Confirm the watch runs and that the day and date both advance cleanly and fully through the night cycle. Sluggish or incomplete changes are a sign the movement needs attention. |
| Case | Inspect the lug edges and crown area where plating wears first. Light thinning is common and expected; bare metal showing through or pitting underneath is a harder problem. The hidden lug design can trap grime, so look in those recesses as well. |
| Crown | Work the crown through all positions and confirm it pulls and pushes smoothly with no grinding or wobble. Also note that this watch is not suitable for water exposure, regardless of how it was originally rated. |
The Movement
The caliber 645 is a Swiss-made automatic movement that Hamilton used during its transition period in the early 1970s. It drives the quick-change day and date complication through a mechanism that advances both displays at or near midnight. At this age, a full service with fresh lubricants is the best way to keep it running reliably.