Chronograph B
1968–1971 · Stainless Steel · Manual Wind
About the Chronograph B
Made from 1968 through 1971, the Chronograph B is one of Hamilton's serious tool watches from the late 1960s, built around the caliber 643 manual wind movement. The case is stainless steel with a circular profile, and the dial runs a two-toned arrangement with a black field, two white subseconds registers, and a tachometer scale around the perimeter. Raised gold hour markers ring the dial in place of numerals. The Chronograph B was part of Hamilton's tachometer chronograph line, sitting alongside the Chronograph A in the same catalog years.
Finding a clean example means paying close attention to those white subdials, which are prone to yellowing or staining over the decades. The tachometer chapter ring is worth scrutinizing too, as fading or flaking there is common and hard to restore. The original stainless steel bracelet is rarely found with the watch at this point, so a replacement strap is the norm rather than the exception.
From the Catalog
Hamilton marketed the Chronograph B in 1968 as an exceptionally accurate timepiece with 1/5-second stop watch timing, a tachometer, and a 0 to 30-minute recorder, priced at $99.50 in stainless steel. By 1970 the price had moved to $110.00, with the watch listed as offering two registers.
Hamilton Catalog Images
1968
1970
1971
What to Look For
| Dial | Look hard at the two white subseconds registers. Yellowing, staining, and discoloration are common on these subdials and should factor into what you're willing to pay. Check the tachometer scale around the perimeter for fading or flaking print. The raised gold hour markers can sometimes come loose or shift, so confirm they're all seated flat. |
| Crystal | Check for deep scratches or crazing in the crystal. A fogged or heavily scratched crystal often signals the watch hasn't been serviced or cared for in years, and it's worth factoring in replacement cost. |
| Movement | The caliber 643 is a manual wind chronograph, and dried lubricants are a genuine concern on any movement this age. Parts for this caliber, including hour and minute hands, can be difficult to source, and repair costs on a vintage chronograph movement run higher than a standard three-hander. Before buying, confirm the chronograph function starts, stops, and resets cleanly, and that the watch runs consistently. |
| Case | Stainless steel cases from this era hold up well, but check the lugs for wear and confirm the case hasn't been aggressively polished. The caseback can be stubborn to open on these, so if a seller can't confirm the caliber, factor that uncertainty in. Look for dings or dents around the pushers. |
| Crown | Pull the crown gently through its positions to confirm it moves and sets without slipping or grinding. A damaged crown or worn stem on a chronograph is a more involved repair than on a simpler watch. |
The Movement
The caliber 643 is a 17-jewel manual wind chronograph movement. It needs regular winding and powers both the timekeeping and the stop-start chronograph function, along with a 30-minute register. Servicing this caliber requires a watchmaker comfortable with chronograph work, and parts availability is genuinely limited, which makes finding a well-serviced example that much more worthwhile.