Star Micronics SB-20RII

Est. $90,000 - $150,000 Specs verified 2026-10-03 · starcnc.com Updated 2026-10-03

Image: starcnc.com, Star Micronics

Key Specifications

Max Spindle

Max. 10,000min-1 (OP: Max. 8,000min-1)

Spindle Power

2.2kW (cont)/3.7kW (10min/25%ED)

max machining diameter

20 mm (25/32 in), optional 25.4 mm (1 in)

max headstock stroke guide bush

205 mm (8 in)

max headstock stroke non guide bush

Bar diameter x 2.5 (max 50 mm)

main spindle speed

10,000 RPM (8,000 RPM with 25.4mm option)

How much does the Star Micronics SB-20RII cost?

Estimated price range

Est.$90,000 - $150,000

Our best estimate for a swiss-type lathe in this class — not a quote from Star Micronics. Configuration moves it a long way.

Overview

The Star Micronics SB-20RII is a 7-axis Swiss-type lathe for 20 mm (25/32 in) bar that can be ordered with a 25.4 mm (1 in) capacity. In standard form both spindles run to 10,000 RPM. With the 25.4mm option both drop to 8,000 RPM, so the larger bar is paid for in top speed.

That trade deserves a decision up front. A shop that mostly runs small diameters keeps the full 10,000 RPM by staying with 20 mm (25/32 in). A shop with regular one-inch work gains the capacity and gives up a fifth of its maximum speed, which only hurts on the smallest turned diameters and drills. Spindle power is the same either way in Star's table: 2.2 kW continuous and 3.7 kW at the 10 min, 25% ED rating on the main, 1.5 kW continuous and 2.2 kW at 15 min, 60% ED on the sub.

Tooling follows a similar either-or. The turning post holds 6 tools at 12 mm or 5 tools at 16 mm. The sub spindle side has 4 stations as standard and can be expanded to 6, worth specifying when back-end work includes several drilled and tapped features.

Headstock stroke is 205 mm (8 in) with the guide bush, and bar diameter x 2.5 up to a maximum of 50 mm without it. Rapid traverse is 35 m/min. The machine weighs approximately 2,000kg, measures 2,070 x 1,095 x 1,775 mm, carries a 180 L coolant tank and runs a Fanuc 0i-TF Plus control.

Full Specifications

Parameter	Value
Max Machining Diameter	20 mm (25/32 in), optional 25.4 mm (1 in)
Max Headstock Stroke Guide Bush	205 mm (8 in)
Max Headstock Stroke Non Guide Bush	Bar diameter x 2.5 (max 50 mm)
Main Spindle Speed	10,000 RPM (8,000 RPM with 25.4mm option)
Main Spindle Power	2.2 kW continuous / 3.7 kW (10 min, 25% ED)
Sub Spindle Speed	10,000 RPM (8,000 RPM with 25.4mm option)
Sub Spindle Power	1.5 kW continuous / 2.2 kW (15 min, 60% ED)
Number of Axes	7
Turning Tools	6 tools (12 mm) or 5 tools (16 mm)
Sub Spindle Stations	4 standard, expandable to 6
Rapid Feed Rate	35 m/min
CNC Control	Fanuc 0i-TF Plus
Coolant Tank	180 L
Machine Weight	Approx. 2,000kg
Dimensions	2,070 x 1,095 x 1,775 mm
Max Turning Diameter	ø20mm (25/32in) OP: ø25.4mm (1in)
Turret Stations	6 tools (ø12mm) / 5 tools (ø16mm)
Max Spindle Speed	Max. 10,000min-1 (OP: Max. 8,000min-1)
Spindle Motor Power	2.2kW (cont)/3.7kW (10min/25%ED)
Rapid Traverse X	35m/min (X1m Y1, Z1, X2, Z2)
Coolant Capacity	180ℓ
CNC Control	Fanuc 0i-TF Plus
Floor Space	2,070 × 1,095× 1,775mm

Specifications sourced from starcnc.com — verified 2026-10-03

Strengths & Limitations

Strengths

10,000 RPM on both main and sub spindles in the standard 20 mm (25/32 in) form
Optional 25.4 mm (1 in) bar capacity
7 axes, with sub spindle tooling of 4 stations expandable to 6
Runs with the guide bush at 205 mm (8 in) of stroke, or without it up to a maximum of 50 mm
Sub spindle rated 1.5 kW continuous / 2.2 kW (15 min, 60% ED)

Limitations

The 25.4mm option reduces both spindles from 10,000 RPM to 8,000 RPM
Choosing 16 mm shanks cuts the turning post from 6 tools to 5 tools
Main spindle power is 2.2 kW continuous; the SB-38 is listed at 7.5kw (continuous)
Guide-bushless stroke is limited to bar diameter x 2.5, maximum 50 mm

Best For

Bar parts up to 20 mm (25/32 in), or 25.4 mm (1 in) with the option Small-diameter work that needs 10,000 RPM on both spindles Parts with back-end work spread over 4 to 6 sub spindle stations Mixed long and short parts, switching between guide-bush and guide-bushless running

Frequently Asked Questions

01 What changes with the 25.4mm option on the SB-20RII?

Maximum machining diameter goes from 20 mm (25/32 in) to 25.4 mm (1 in). Maximum speed of both the main and the sub spindle goes from 10,000 RPM to 8,000 RPM. Star's table gives one set of power figures, 2.2 kW continuous / 3.7 kW (10 min, 25% ED) on the main spindle, with no separate rating for the option.

02 How many axes and tools does the SB-20RII have?

Star lists 7 axes. The turning post takes 6 tools with 12 mm shanks or 5 tools with 16 mm shanks. Sub spindle tooling is 4 stations as standard, expandable to 6.

03 What is the headstock stroke of the SB-20RII?

With the guide bush the maximum headstock stroke is 205 mm (8 in). Without the guide bush it is bar diameter x 2.5, to a maximum of 50 mm. The machine can therefore be set up either for long, slender parts or for short parts that do not need guide-bush support.

04 How does the SB-20RII compare with the SB-20R Type G?

Both are ø20mm (25/32in) machines with 35 m/min rapid traverse. The SB-20RII runs a Fanuc 0i-TF Plus control, weighs approximately 2,000kg and takes 6 tools (12 mm) or 5 tools (16 mm), with ø25.4mm (1in) bar as an option. The SB-20R Type G is listed with a Fanuc 31i-B control, a weight of 1,700 kg and 6 tools (ø12mm) / 7 tools (ø10mm).

05 What are the installation figures for the SB-20RII?

The machine weighs approximately 2,000kg and its dimensions are 2,070 x 1,095 x 1,775 mm. The coolant tank holds 180 L. Star's table for this model gives no electrical supply or air figures, so request those with the installation drawing.