Thin-o-matic T-650
1959–1962 · 10k Rolled Gold Plate / Stainless Steel · Automatic
About the Thin-o-matic T-650
The Thin-o-matic T-650 appeared in Hamilton's catalog in 1959, running the caliber 663 or 666, both 17-jewel automatic movements. The T-650 is part of Hamilton's Thin-o-matic family, which prioritized slimmer case profiles through automatic winding without a traditional rotor. Its 10k Rolled Gold Plate case with stainless steel back gave it an accessible price point relative to solid gold models, and Hamilton marketed it with waterproof ratings, a selling point that mattered to buyers in the late 1950s.
Finding a T-650 today means paying close attention to the case plating, since Rolled Gold Plate wears through at the lugs and high-contact points over decades of use. The dial is worth examining closely: the embossed yellow numerals and markers with luminous dots and a pearled minute track are distinctive details that can show age or amateur refinishing if the watch was ever improperly restored.
From the Catalog
Hamilton listed the T-650 at $79.50 on a strap and $89.50 on a bracelet in 1959, positioning it as a serious automatic with waterproof capability, a rolled gold plate case, and a dial that combined embossed numerals and markers with luminous dots and a pearled minute track.
Hamilton Catalog Images
1959
1960
1961
What to Look For
| Dial | Look carefully at the embossed yellow numerals and markers. Embossed details are vulnerable to over-cleaning and improper restoration. The luminous dots should be present and intact, though some aging of the lume material is expected and normal. A repainted or refinished dial will lose the crisp definition of the embossing and the texture of the pearled minute track. |
| Crystal | Check for chips, deep scratches, or a replacement crystal that sits unevenly in the bezel. An ill-fitting crystal on a watch this age often means someone used a generic replacement rather than a period-correct part. |
| Movement | The caliber 663 and 666 share an architecture where the wheel arbors are long and require precise alignment when the bridges are reinstalled. A movement that has been serviced carelessly can run rough or erratically because of this. Ask about service history, and if possible, observe the sweep seconds hand for any stuttering or inconsistency in motion. |
| Case | Rolled gold plate wears through over time, particularly at the lugs and case edges. Examine those areas under good light for brass showing through. Some wear is honest and expected, but deep wear through to the base metal affects both appearance and long-term durability. |
| Crown | The crown should pull out and push in smoothly with no looseness or wobble. A worn or replaced crown can compromise the waterproof rating Hamilton originally specified for this model, and it may indicate stem wear inside the movement as well. |
The Movement
The T-650 runs either the caliber 663 or the caliber 666, both 17-jewel automatic movements developed as part of Hamilton's effort to produce thinner self-winding watches. Rather than a conventional full rotor, these movements use a different winding architecture to keep the overall case height down. Both calibers are capable movements, but the long wheel arbors require careful handling during service to keep everything running smoothly.