Thin-o-matic T-475 Calendar
1960 · 10k YGF / SSB
About the Thin-o-matic T-475 Calendar
Made only in 1960, the Thin-o-matic T-475 Calendar is part of Hamilton's Thin-o-matic family, which brought automatic movement technology into slimmer, more dress-oriented cases. The T-475 Calendar adds a date window to the standard T-475 configuration, running on the caliber 668. The case is 10k yellow Gold Filled with a stainless steel back, and the dial features yellow embossed markers with luminous dots and a pearled track on a white rim over a gold-colored dial background. Hamilton originally listed it as weatherproof, which was a meaningful selling point in 1960.
Finding a clean example means paying close attention to the date window surround and the dial's white rim, both of which can show discoloration or spotting if the watch has taken on any moisture over the decades. The gold-colored dial background on these is particular about humidity, and the luminous dots on older examples may have darkened or contracted. The one-year production run keeps supply genuinely limited, so condition matters more here than on models Hamilton made across multiple catalog years.
From the Catalog
Hamilton listed the T-475 Calendar at $95.00 in 1960, positioning it as a gold-filled dress piece with practical calendar function, weatherproof construction, and the option of either a strap or bracelet configuration.
Hamilton Catalog Images
1960
What to Look For
| Dial | Look closely at the white rim around the perimeter and the gold-colored dial background. Moisture intrusion over sixty-plus years can leave spotting, separation, or tide marks, especially near the date window. The embossed markers should be crisp, not worn flat. |
| Crystal | Check for chips or deep scratches, particularly near the date window cutout where crystals on calendar models tend to take more stress. A fogged or crazed crystal is worth replacing before purchase if the seller is open to it. |
| Movement | Ask when the caliber 668 was last serviced. Oil in a movement this age dries out and creates friction that can stop the watch entirely, even if it winds and sets normally. A watch that runs but loses time dramatically is usually telling you it needs a full service. |
| Case | The 10k gold-filled case can show wear through to the base metal at the lugs and back edges. Examine those areas in good light. The stainless steel back is more durable, but check that it seats evenly and shows no signs of forced opening. |
| Crown | The crown should pull out smoothly to both the hand-set and date-set positions without slipping. A crown that feels loose or strips out is a straightforward fix but worth flagging before purchase. |
The Movement
The caliber 668 is a Swiss-made automatic movement produced for Hamilton during its transition toward Swiss-sourced ebauches in the early 1960s. It winds through a rotor that captures motion in both directions, so the watch keeps itself wound during normal daily wear. At its core, it is a reliable and well-finished movement, though like all movements of this era it benefits considerably from a proper cleaning and fresh lubrication.