Bulova 6CMA & 6CMAC: Compact Movements with Refined Engineering

The Bulova 6CMA and 6CMAC represent a specialized branch of Bulova's 6¾ ligne mechanical movement family, developed in the mid-20th century. These calibers were designed for elegant, compact wristwatches, primarily targeted at the women’s watch market. Known for their slim profiles, clean engineering, and durability, both movements served as trusted engines for Bulova’s fine dress watches through the 1950s and 1960s.

General Specifications

These movements follow the time-only format, with no seconds hand, making them ideal for dress watches where elegance and simplicity take center stage.

Movement Design & Structure

The 6CMA and 6CMAC are structurally similar to other 6-ligne Bulova calibers like the 6CL and 6CT, but may include refinements in shock protection, jewel placement, or bridge design. The suffix “C” typically indicates either an evolution in movement layout or compliance with updated manufacturing standards.

Key features include:

• Two-bridge layout: one for the barrel, one for the train wheels

• Steel balance wheel with a flat hairspring and regulator

• Polished and high-efficiency gear train wheels

• Manual keyless works with strong click spring and clutch mechanism

• Clean plate finishing with minimal ornamentation for easier servicing

The overall architecture supports low-friction operation, contributing to smooth winding and stable amplitude when fully serviced.

Applications in Bulova Watches

The 6CMA/6CMAC movements were used in:

• Ladies’ watches between the 1950s and early 1970s

• Timepieces featuring gold-filled or solid gold cases

• Watch styles marketed as gift or formalwear watches

• Models with minimalist dials—often just hour markers and two hands

These watches were part of Bulova’s commitment to combining aesthetics with affordability during the post-war economic boom, often sold at jewelry counters and department stores.

Service Considerations

For modern watchmakers and restoration specialists, the 6CMA and 6CMAC movements are straightforward to maintain—with proper care and tooling.

Watchmaker Notes:

• Always replace old mainsprings with new alloy versions to restore full torque.

• These movements lack a seconds hand, so positional regulation requires careful balance adjustment.

• Use Moebius 9010 on pivots and 8200 grease on barrel arbor contact points.

• Check the clutch wheel and winding pinion for signs of wear, as these are high-friction components.

The balance staff and jewels in these small movements are delicate but replaceable with donor parts or skilled micro-repairs.

Restoration & Collector Value

Although not complicated or widely recognized among high-end collectors, watches containing the 6CMA and 6CMAC movements are popular among vintage enthusiasts and restorers. Their enduring mechanical reliability makes them a favorite for refurbishment and resale.

Why they’re still sought after:

• Strong examples of mid-century craftsmanship

• Frequently found in well-preserved vintage cases

• A good entry point into vintage watch collecting

• A perfect match for those who value refined, minimalist wristwatches

Once cleaned and regulated, these movements continue to perform with impressive accuracy—often within ±30 seconds per day.

Conclusion

The Bulova 6CMA and 6CMAC movements embody what made Bulova such a respected name in American watchmaking: precision, elegance, and mechanical dependability, all packed into a tiny form factor. Whether you’re restoring one, collecting for heritage, or simply admiring vintage watches for their quiet charm, these movements remind us that true craftsmanship often comes in small packages.