Star Micronics SB-12R Type G

$80,000 - $130,000 Updated 2026-03-14

Key Specifications

max machining diameter

13 mm (33/64 in)

max headstock stroke guide bush

205 mm (8 in)

max headstock stroke non guide bush

Bar diameter x 2.5 (max 30 mm)

main spindle speed

15,000 RPM

main spindle power

2.2 kW continuous / 3.7 kW (10 min, 25% ED)

sub spindle speed

12,000 RPM

Overview

The Star Micronics SB-12R Type G is a compact sliding headstock CNC automatic lathe designed for high-precision machining of small-diameter components up to 13mm. As part of Star's SB (basic sliding headstock) lineup, it delivers an accessible entry point into Swiss-type turning without sacrificing the precision and reliability that Star Micronics is known for. The main spindle reaches 15,000 RPM with 2.2 kW continuous power (3.7 kW peak), providing excellent surface speeds for small-diameter work in materials ranging from free-machining brass to stainless steel and titanium alloys.

The SB-12R Type G features a versatile 17-position tool layout with a 4-spindle sleeve holder offering both front and rear tool stations. This configuration allows simultaneous machining operations that reduce cycle times on complex small parts. The sub spindle runs at up to 12,000 RPM with 0.55 kW continuous power, enabling back-working operations including drilling, tapping, and finish turning without secondary handling. Cross drilling units are available in 4-spindle, 5-spindle, or cartridge-type configurations to match specific part requirements.

One of the SB-12R Type G's key advantages is its switchable guide bushing system. Operators can run with the guide bushing engaged for long, slender parts requiring superior concentricity, or remove it for shorter parts where non-guide-bush mode reduces bar remnant waste and simplifies setup. This dual-mode capability makes the machine significantly more versatile than dedicated guide-bush-only models, allowing shops to handle a wider range of part geometries on a single platform.

The machine runs on a Fanuc 0i-TD control with proven reliability and widespread familiarity among operators. At 1,750 kg and a footprint of 2,070 x 1,177 mm, the SB-12R Type G fits comfortably in shops where floor space is at a premium. With rapid traverse rates of 35 m/min on all primary axes and a 180-liter coolant tank, this machine is built for production environments running lights-out or multi-machine attended cells producing medical components, electronic connectors, watch parts, and precision fasteners.

Full Specifications

Parameter	Value
Max Machining Diameter	13 mm (33/64 in)
Max Headstock Stroke Guide Bush	205 mm (8 in)
Max Headstock Stroke Non Guide Bush	Bar diameter x 2.5 (max 30 mm)
Main Spindle Speed	15,000 RPM
Main Spindle Power	2.2 kW continuous / 3.7 kW (10 min, 25% ED)
Sub Spindle Speed	12,000 RPM
Sub Spindle Power	0.55 kW continuous / 1.1 kW (15 min, 40% ED)
Tool Positions	17
Sleeve Holder	4-spindle (front 4 / rear 4 tools)
Rapid Feed Rate	35 m/min (X1, Y1, Z1, X2, Z2)
Guide Bushing	Switchable (guide bush / non-guide bush)
CNC Control	Fanuc 0i-TD
Coolant Tank	180 L
Machine Weight	1,750 kg (3,858 lb)
Dimensions	2,070 x 1,177 x 1,760 mm

Specifications sourced from starcnc.com — verified 2026-03-28

Strengths & Limitations

Strengths

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Limitations

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Best For

Medical device manufacturers producing micro screws, implant pins, dental abutments, and surgical instrument shafts under 13mm diameter Electronics and connector manufacturers producing precision contact pins, terminal posts, and miniature shafts in high volumes Watch and clock component shops machining stems, crowns, pushers, and small turned parts requiring fine surface finishes Contract shops seeking a versatile small-diameter Swiss lathe with guide bush flexibility to handle diverse part families Automotive sensor and fuel system component manufacturers running small-diameter precision parts in medium to high volumes Shops looking for an entry-level Star Swiss lathe with production-grade capability and a compact footprint

Frequently Asked Questions

01 What does a Star Micronics SB-12R Type G cost?

A new Star SB-12R Type G typically runs $80,000-$130,000 depending on configuration, optional tooling packages, bar feeder, and regional pricing. Used SB-12R machines in good condition trade in the $40,000-$70,000 range depending on age, hours, and included accessories. Star holds value well in the secondary market due to the brand's reputation for longevity.

02 What is the difference between guide bush and non-guide bush mode on the SB-12R?

In guide bush mode, the bar stock passes through a rotating guide bushing that supports the workpiece close to the cutting point, providing superior rigidity and concentricity for long, slender parts. In non-guide bush mode, the guide bushing is removed, allowing the headstock to act as a conventional sliding headstock. This reduces bar remnant waste (the unsupported length that cannot be machined) and simplifies setup for shorter parts where guide bush support is unnecessary.

03 How does the SB-12R compare to the Star SR-10J?

The SB-12R Type G handles slightly larger bar stock (13mm vs 10mm) and has more tool positions (17 vs approximately 14). The SR-10J offers more advanced control (Fanuc 32i-B) and is positioned as a higher-capability machine for complex small parts. The SB-12R is better suited for shops that need the extra 3mm of bar capacity and want a straightforward, cost-effective Swiss lathe.

04 Can the SB-12R run unattended?

Yes. With a magazine bar feeder, parts catcher, and proper tooling setup, the SB-12R Type G is fully capable of lights-out production. The Fanuc 0i-TD control supports tool life management and bar-end detection. Many shops run SB-series machines unattended on evening and weekend shifts, particularly on established jobs with proven programs.

05 What materials can the SB-12R machine?

The SB-12R handles the full range of Swiss-type lathe materials: free-machining brass, aluminum, carbon steel, stainless steel (303, 304, 316), titanium alloys (Ti-6Al-4V for medical), and engineering plastics like PEEK and Delrin. The 15,000 RPM spindle provides adequate surface speed for most materials at 13mm and below, though very hard alloys like Inconel may require reduced speeds.

06 What industries use the Star SB-12R?

The SB-12R is widely used in medical device manufacturing (bone screws, dental implants, surgical pins), electronics (connector pins, terminal contacts), automotive (sensor components, fuel injector parts), watch/clock making, and general precision contract machining. Its sweet spot is high-volume production of complex small parts under 13mm diameter.