Chronomatic C
1971–1976 · Stainless
About the Chronomatic C
Made from 1971 through 1976, the Chronomatic C is a rectangular stainless steel chronograph running on Hamilton's caliber 630, a self-winding movement with a micro rotor. The two-register dial includes a one-fifth-second recorder track and a time zone dial, packing a surprising amount of function into a case shape more commonly associated with dress watches. The Chronomatic line sits within Hamilton's broader push into automatic chronograph territory in the early 1970s, and the C variant is one of the more distinctive pieces in that family thanks to its rectangular case.
Finding one in good shape takes patience. The combination of a rectangular case, automatic movement, and full chronograph function is unusual enough that when a clean example turns up, it tends to move quickly.
From the Catalog
Hamilton described the Chronomatic C in period catalogs as a self-winding chronograph with a two-register dial, one-fifth-second recorder track, and time zone dial, listed at $240 in 1972.
Hamilton Catalog Images
1971
1972
1973
1975
1976
What to Look For
| Dial | Look closely at the applied indices under magnification. Any separation of the markers, greenish residue at the base, or uneven patina around the registers suggests the dial has been exposed to moisture at some point. The recorder track and time zone dial printing should be crisp, not faded or flaking. |
| Crystal | Check for deep scratches or crazing. A replacement crystal on a rectangular case can be harder to source than you'd expect, so confirming the fit is correct and the crystal sits flush matters here. |
| Movement | The caliber 630 uses a micro rotor, and replacement parts for this generation of movement are no longer available. A cannon pinion that has gone loose is a known issue and means the hands can slip out of sync with the actual time. Ask whether the watch has been recently serviced, and confirm the chronograph functions are working before purchase. |
| Case | The case back can be tricky to open without the right tool, so pry marks or damage around the back edge are worth flagging. |
| Crown | Check that the crown threads in smoothly and seats properly. Even though this watch carries a water-resistant rating, no vintage watch should be trusted near water at this age without a fresh pressure test and new seals. |
The Movement
The caliber 630 is an automatic chronograph movement built around a micro rotor, a small weighted rotor that sits within the movement plane rather than swinging around the full diameter of the case. This design is part of what makes a rectangular automatic chronograph possible. The movement winds from the natural motion of the wrist, so there is no need to hand-wind during regular wear, though the small rotor is less efficient at winding than a full-sized one.