Thinline 6511
1968–1970 · 10k Rolled Gold Plate / Stainless Steel · Manual Wind
About the Thinline 6511
Made from 1968 through 1970, the Thinline 6511 is a manual-wind dress watch from Hamilton's Thinline family, running the caliber 639 in a 10K yellow Gold Filled top with stainless steel back. The case is round with swept lugs, and the white dial uses applied gold markers with no hour numerals, giving it a clean, minimal look that suited the late-1960s taste for understated dress watches. A subseconds hand sits at the 6 o'clock position. The Thinline 6511 is closely related to the 6510 and 6505, all part of Hamilton's thin-profile manual-wind lineup from the same era.
The known dial variant with black highlights adds a bit of contrast to an otherwise all-white dial, and finding one in original, unpolished condition is worth the extra attention. The applied gold markers are prone to losing their luster or coming loose on older examples, so a close look at the dial under good light is time well spent. At its original price of $59.50, this was a moderately priced entry in the Thinline lineup, which means surviving examples weren't treated as heirlooms the way pricier models sometimes were.
From the Catalog
Hamilton listed this model simply as a 10K yellow top at $59.50, placing it in the middle tier of the Thinline lineup for 1968.
Hamilton Catalog Images
1968
What to Look For
| Dial | Check that the applied gold markers are all present, flat against the dial, and free of separation or corrosion at their bases. On the variant with black highlights, look for flaking or wear to those details. Any spotting or discoloration on a white dial is hard to ignore and nearly impossible to reverse. |
| Crystal | Confirm the crystal is properly seated and free of deep scratches. A replacement crystal is straightforward, but make sure any replacement matches the correct profile for this case. |
| 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 real friction problems in this caliber and can stop the watch entirely. Ask whether the watch has been recently serviced. |
| Case | Inspect the gold-filled top for wear-through, especially on the lugs and case sides where contact is highest. The case back can be tricky to open without the right tools, and evidence of prying attempts often shows up as marks around the edge of the back. |
| Crown | Test the crown through its positions and confirm it winds smoothly and sets the hands without slipping. The set lever tip in the 639 can break during stem removal if the work is done carelessly, so any roughness in the feel is worth investigating before purchase. |
The Movement
The caliber 639 is a 17-jewel manual-wind movement that Hamilton used across several of its dress watch lines in the late 1960s. It is a thin movement by design, which is part of what made it suitable for the Thinline series, but that compact layout means the parts are tightly stacked with minimal clearance between them. It keeps good time when properly serviced, but it rewards careful, experienced handling during any work.