The Star SR-20RIII is a Swiss-type sliding-headstock automatic lathe with a reputation for repeatable small-part accuracy that has made it a staple in medical, aerospace, and precision component shops. It machines bar up to 20 mm (0.787") through a revolving guide bush with a 205 mm (8") maximum headstock stroke, pairing a 10,000 RPM main spindle rated 2.2 kW continuous / 3.7 kW (5 HP) 15-minute with an 8,000 RPM back spindle rated 1.5 / 2.2 kW and 20 mm chucking capacity for simultaneous front and back machining and complete part pickoff. Tooling includes a 6-station gang tool post, 4-spindle front and rear sleeve holders, a 2-spindle front deep-hole holder, a back 4-spindle unit, and power-driven cross tools running to 8,000 RPM on a 1.2 kW drive, with 0.01 degree C-axis indexing on both spindles. Rapid traverse is 35 m/min (1,378 ipm) on X, Y, Z, XB, and ZB, and motion is managed by a Fanuc Series 30i-Model A control. The unit is equipped with an LNS Alpha ST320 magazine bar feeder for lights-out running, a high-pressure coolant system, a Tri-Mist 850 mist collector, and a chip conveyor.
Compared with the earlier Star SR-20RII and the original SR-20R, the SR-20RIII is a meaningful step forward in capability. The RIII pairs its 10,000 RPM main spindle with an 8,000 RPM back spindle and room for up to 10 power-driven tools, giving it the flexibility to finish milled, cross-drilled, and back-worked features in a single cycle instead of sending parts to secondary operations. Star's motion control system coordinates the front and back tool groups for overlapping cuts, and 35 m/min rapids keep non-cutting time short on high-volume runs. For a shop stepping up from an SR-20R or SR-20RII, the RIII delivers more capable multi-axis Swiss machining on the same compact 20 mm platform - a better machine, not merely a later one.