The Tissot caliber 6912 is a manual-winding chronograph movement produced in the 1970s, and it forms part of Tissot’s vintage chronograph lineup based on the Lemania 1872/1873 movement family. As a product of the SSIH era—when Tissot collaborated closely with Omega and Lemania—the 6912 benefits from robust construction, proven mechanical architecture, and widespread parts compatibility. Like its siblings (calibers 6922, 6942, and 6952), the 6912 requires regular maintenance to preserve its precision, reliability, and chronograph functionality.

Overview of the Caliber 6912

The Tissot 6912 is a manual-wind, two-register chronograph movement. It features:

• A central chronograph seconds hand

• A 30-minute totalizer at 3 o’clock

• A running seconds subdial at 9 o’clock

The layout is typical of 1970s sports and racing-style chronographs. The movement beats at 18,000 vibrations per hour (2.5 Hz) and uses a cam-lever chronograph mechanism rather than a column wheel, making it simpler and more durable for everyday use.

Watches powered by the 6912 were usually cased in stainless steel with bold, tool-watch aesthetics, designed to appeal to a younger, more adventurous clientele.

Service Interval

Like most vintage mechanical chronograph movements, the 6912 should be fully serviced every 4 to 6 years. This is essential to maintain proper lubrication, preserve the function of the chronograph system, and prevent irreversible wear.

Early signs that the watch needs service include:

• Chronograph seconds skipping or stuttering

• Pushers becoming stiff or unresponsive

• Inaccurate timekeeping or reduced amplitude

• Reset hands failing to return precisely to zero

Even if the movement seems to function, it may still be operating with dried lubricants that could damage critical components over time.

Full Service Procedure

A qualified watchmaker experienced with vintage Lemania-based movements should follow these steps during a full overhaul:

1. Complete disassembly of the movement, including the chronograph mechanism.

2. Ultrasonic cleaning of all components to remove old oils and contaminants.

3. Visual inspection for wear and damage, especially on the chronograph cams, levers, and wheels.

4. Replacement of worn parts, using original or compatible vintage spares.

5. Lubrication with modern oils and greases at all prescribed contact points.

6. Reassembly with fine adjustment of the chronograph engagement and reset mechanism.

7. Timing regulation in several positions using timing machines.

8. Case resealing, with optional replacement of pusher gaskets, crown seals, and the caseback gasket to help reduce dust or moisture entry.

Common Points of Wear

Even well-designed movements like the 6912 experience wear over decades. The most common issues include:

• Chronograph reset hammer wear or misalignment

• Heart cams developing grooves that prevent clean resets

• Sliding clutch wear or improper contact, affecting engagement

• Main spring fatigue, leading to reduced power reserve

• Worn pushers or degraded gaskets, allowing dust or moisture to enter the case

These components must be carefully checked and replaced as needed to ensure reliable operation.

Handling Tips

To reduce wear and extend the lifespan of the movement:

• Stop the chronograph before resetting—never reset while the chronograph is running.

• Wind the watch gently once per day if worn regularly. Avoid forcing the crown.

• Keep away from moisture and magnetic fields, especially if the seals have not been recently replaced.

• Store in a clean, dry place, ideally in a watch box with stable temperature and humidity.

Conclusion

The Tissot caliber 6912 is a dependable, vintage manual chronograph movement that continues to deliver strong performance when properly maintained. As a member of the Lemania 1872/1873 family, it benefits from a proven design, accessible servicing, and lasting mechanical quality. Regular servicing, careful handling, and respect for its mechanical complexity will keep this movement running smoothly for many years. Whether you are a collector, daily wearer, or enthusiast of vintage Swiss chronographs, the 6912 offers an excellent combination of utility and heritage.