Machine Comparison
Star Micronics SB-20RII vs Star Micronics SK-51 Type A
Star Micronics vs Star Micronics · Swiss-Type Lathes
Summary
The Star Micronics SB-20RII and the Star Micronics SK-51 Type A are in different size classes and serve different jobs. The SB-20RII is a small-bar Swiss-type lathe for stock up to 20 mm (25/32 in), or 25.4 mm (1 in) as an option. The SK-51 Type A takes bar up to 51 mm (2 in) and weighs 6,600 kg against approx. 2,000 kg.
The SK-51 Type A brings the power: 7.5 kW continuous and 11 kW on the 15-minute rating, against 2.2 kW continuous and 3.7 kW on the 10-minute rating. Its tool capacity is listed at 12 against 6 tools at 12 mm. The SB-20RII is faster on the second end, with a sub-spindle at 10,000 RPM (8,000 RPM with the 25.4 mm option) against 5,000 RPM. Controls are Fanuc 0i-TF Plus and FANUC 32i-B.
Specifications Comparison
| Specification | Star Micronics SB-20RII | Star Micronics SK-51 Type A |
|---|---|---|
| Max Turning Diameter | ø20mm (25/32in) OP: ø25.4mm (1in) | Ø51mm (2in.) ▲ |
| Spindle Power | 2.2kW (cont)/3.7kW (10min/25%ED) | 7.5kW (continuous)/11kW (15min.) ▲ |
| Sub-Spindle Speed | 10,000 RPM (8,000 RPM with 25.4mm option) ▲ | 5,000 RPM |
| Tool Capacity | 6 tools (ø12mm) / 5 tools (ø16mm) | 12 ▲ |
| Rapid Traverse | 35m/min (X1m Y1, Z1, X2, Z2) ▲ | 20m/min |
| Control | Fanuc 0i-TF Plus | FANUC 32i-B |
| Machine Weight | Approx. 2,000kg | 6,600kg |
| Floor Space | 2,070 × 1,095× 1,775mm | 2,800mm W x 2,070mm D x 2,130mm H |
Advantages
Star Micronics SB-20RII
- Sub-spindle to 10,000 RPM (8,000 RPM with the 25.4 mm option) against 5,000 RPM
- Approx. 2,000 kg against 6,600 kg, on a 2,070 × 1,095 mm footprint against 2,800 x 2,070 mm
- Sized for bar up to 20 mm (25/32 in), with guide-bush or guide-bushless running for long and short parts
Star Micronics SK-51 Type A
- 51 mm (2 in) maximum turning diameter against 20 mm, or 25.4 mm (1 in) with the option
- 7.5 kW continuous and 11 kW (15 min) spindle power against 2.2 kW and 3.7 kW (10 min)
- Tool capacity listed at 12 against 6 tools
Verdict
Different size classes, different work. The Star Micronics SK-51 Type A is the choice for bar parts up to 51 mm (2 in) that take heavy cuts, with 7.5 kW continuous at the spindle and a 6,600 kg machine behind it. The Star Micronics SB-20RII fits small-diameter work up to 20 mm (25/32 in), where a 10,000 RPM sub-spindle matters more than power and the machine takes far less floor. Part diameter settles which one a shop needs.