Thinline 6509
1968–1970 · 10k RGP / Stainless · Manual Wind
About the Thinline 6509
The Thinline 6509 appeared only in 1968, making it a single-catalog-year model within Hamilton's Thinline family. It runs on the caliber 639, a 17-jewel manual wind movement, housed in a cushion-shaped case crafted from 10K yellow Rolled Gold Plate over stainless steel. The dial is silver with applied gold numerals at 3, 9, and 12, applied gold markers filling the remaining hour positions, and a subseconds register at 6 o'clock. The Thinline family runs deep in Hamilton's catalog history, and the 6509 is one of its more compact, quietly refined expressions.
Finding one in good shape means paying close attention to the dial, since silver dials from this period are prone to spotting and oxidation around the edges, particularly under the crystal where moisture can creep in over decades. The applied gold numerals and markers are worth examining closely under good light, as any that have separated, detached, or shifted will affect both the look and the value considerably. The cushion case shape gives this one a slightly softer, more approachable profile than the rectangular Thinline variants, which makes it an appealing daily wearer if the movement is in good running order.
From the Catalog
Hamilton listed the Thinline 6509 in 1968 at $49.95 on strap, with a bracelet configuration available for $59.95, positioning it as an accessible entry into the dressed-up end of the Thinline lineup.
Hamilton Catalog Images
1968
What to Look For
| Dial | Look carefully at the silver dial for spotting, oxidation, or discoloration along the edges and near the crown opening. Check each applied gold numeral and marker to confirm none have separated, tilted, or gone missing. Any damage to the dial is essentially permanent and will meaningfully affect the watch's desirability. |
| Crystal | Confirm the crystal sits flush with the bezel and is free of cracks or deep scratches that could scatter light across the dial. A hazy or crazing crystal is common at this age and worth factoring into the asking price if replacement is needed. |
| Movement | The caliber 639 has very little clearance between its overlapping parts, and oil in a movement this age has almost certainly dried out. Dried lubricant creates enough friction to stop the watch entirely or cause erratic timekeeping. Ask whether the watch has been recently serviced, and if not, budget accordingly. |
| Case | Examine the rolled gold plate on the case top for wear-through, especially on the lugs and high points of the cushion shape where contact is most frequent. Stainless steel showing through the plating is cosmetic, but deep wear can affect how the watch presents. The case back can be tricky to open without the right tools, so look for signs of prior prying or marring around the edge. |
| Crown | Make sure the crown threads or snaps fully into place and winds the movement smoothly without slipping. A damaged or replaced crown on a watch this age is common, so confirm it matches the case finish if originality matters to you. |
The Movement
The caliber 639 is a 17-jewel manual wind movement that Hamilton used across a range of Thinline and dress watch models during this period. It is a compact, well-built movement with a reputation for accuracy when properly maintained, though its tight construction means a thorough service requires patience and a careful hand. Manual wind means the wearer sets and winds it directly, which is a straightforward relationship with the watch that many collectors genuinely appreciate.