Tornos Sigma 8

The Tornos Sigma 8 is a CNC cam-driven multi-spindle automatic turning machine designed for high-volume production of precision turned parts from bar stock. With eight spindles indexed through eight working positions, the Sigma 8 produces one finished part per index cycle regardless of the number of operations required — making it one of the highest-throughput turning solutions available for parts in the 3–32 mm diameter range. Tornos, headquartered in Moutier, Switzerland, has been building multi-spindle automatics for over a century, and the Sigma 8 represents the pinnacle of their cam-driven multi-spindle technology.

The Sigma 8 operates on the classic multi-spindle principle: eight bar-fed spindles are arranged radially and indexed simultaneously, with each spindle performing a different operation at each station. Turning tools, drilling and boring units, threading attachments, and form tools are arranged at each station, and all stations cut simultaneously during each index cycle. The result is cycle times measured in seconds per part rather than minutes — on many automotive and hydraulic connector parts, the Sigma 8 achieves 2–6 second cycle times that no single-spindle or twin-spindle machine can approach.

Tornos integrates CNC override capability on the Sigma 8, allowing digital control of slide positions and speeds despite the underlying cam-driven mechanical architecture. This hybrid approach preserves the speed advantage of cam actuation while adding the flexibility of CNC adjustment for fine-tuning without replacing cams. The machine handles free-cutting steel, brass, aluminum, and many plastics across bar diameters from 3 mm to 32 mm with the appropriate collet and guide bush configuration. Coolant-through capability, automatic bar feeders, and parts conveyors enable fully unattended production runs measured in hours.

At $800,000–$1,400,000 new depending on tooling configuration and accessories, the Sigma 8 is positioned for dedicated production environments where volumes exceed 500,000 parts per year on a family of similar parts. It competes with the Index MS 16 Plus, Star Micronics multi-spindle systems, and Davenport machines in the high-volume multi-spindle segment. Its Swiss precision, long-established technology, and strong global service network make it a reference standard for precision multi-spindle production.