Star Micronics SR-20JII Type A/B

Est. $150,000 - $250,000 Specs verified 2026-10-03 · ellisontechnologies.com Updated 2026-10-03

Image: starcnc.com, Star Micronics

Key Specifications

Max Spindle

10,000 rpm

Rapid Traverse

35 m/min (X1, X2, Z1, Z2); 24 m/min

Spindle Power

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

max machining diameter

20 mm (25/32 in), optional 23 mm (29/32 in)

max headstock stroke

205 mm (8 in)

sub spindle speed

10,000 rpm

How much does the Star Micronics SR-20JII Type A/B cost?

Estimated price range

Est.$150,000 - $250,000

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 SR-20JII Type A/B is a Swiss-type lathe for 20 mm (25/32 in) bar, optionally 23 mm (29/32 in), offered in two types that differ in the back working unit. Type A has 4 tools on that unit. Type B has 8 tools and a Y axis, and the rapid row lists Y2 at 24 m/min against 35 m/min on X1, X2, Z1 and Z2.

Doubling the back tool count is a bigger step than it sounds. With 4 tools, the back end of a part is limited to a short sequence such as a centre drill, a drill, a tap and a boring or turning tool. With 8 tools and a Y axis, the back working unit can carry a second set for another part number, or place cross holes and flats off the centreline. Shops running families of parts with different back-end features are the natural buyers of Type B.

The front tooling is the same on either type: 6 turning tools on 12 mm shanks and a 5-spindle sleeve holder with 5 tools to the front and 5 to the rear. Neither spindle is the weak one. Main and sub are both listed at 10,000 rpm with 2.2 kW continuous and 3.7 kW on the 10min./25%ED rating, so the extra back tools on Type B have the power behind them to do real cutting.

Maximum headstock stroke is 205 mm (8 in). The control is a FANUC 32i-B, and the machine weighs 2,750 kg on a footprint of 2,250 × 1,200 × 1,700 mm.

Full Specifications

Parameter	Value
Max Machining Diameter	20 mm (25/32 in), optional 23 mm (29/32 in)
Max Headstock Stroke	205 mm (8 in)
Sub Spindle Speed	10,000 rpm
Sub Spindle Power	2.2 kW (continuous) / 3.7 kW (10min/25%ED)
Front Turning Tools	6 tools (12 mm shank)
Sleeve Holder	5-spindle (front 5 / rear 5 tools)
Back Working Unit	Type A: 4 tools / Type B: 8 tools (Y-axis)
Rapid Feed Rate	35 m/min (X1, X2, Z1, Z2), 24 m/min (Y2)
CNC Control	FANUC 32i-B
Machine Weight	2,750 kg
Headstock Stroke	205 mm (8 in)
Max Spindle Speed	10,000 rpm
Spindle Motor Power	2.2 kW (continuous) / 3.7 kW (10min./25%ED)
Turning Tools	6 tools
Bar Capacity	Ø20 mm (25/32 in); Optional (OP): Ø23 mm (29/32 in)
Rapid Traverse Rate	35 m/min (X1, X2, Z1, Z2); 24 m/min
Floor Space Required	2,250 × 1,200 × 1,700 mm

Specifications sourced from ellisontechnologies.com (authorised dealer / distributor, not the manufacturer's own site) — verified 2026-10-03

Strengths & Limitations

Strengths

Type B back working unit carries 8 tools with a Y axis; Type A carries 4 tools
Sub spindle has the same 2.2 kW continuous and 3.7 kW (10min/25%ED) rating as the main spindle, at 10,000 rpm
5-spindle sleeve holder with 5 front and 5 rear tools, beside 6 front turning tools on 12 mm shanks
Optional 23 mm (29/32 in) bar size above the standard 20 mm (25/32 in)
35 m/min rapid traverse on X1, X2, Z1 and Z2

Limitations

Type A is limited to 4 tools on the back working unit, with no Y axis there
Y2 rapid traverse is 24 m/min, slower than the 35 m/min of the other listed axes
The 23 mm (29/32 in) capacity is an option that must be ordered
Front turning tools number 6, far fewer than the 27-position, 41 tools arrangement of the SR-20R IV Type A/B

Best For

Type B: part families with varied or off-centre back-end features Type A: parts whose back end needs 4 tools or fewer, on centre Work that puts heavy cuts on the sub spindle, using its 2.2 kW continuous rating Bar up to 20 mm (25/32 in), or 23 mm (29/32 in) with the option Parts within a 205 mm (8 in) headstock stroke

Frequently Asked Questions

01 What is the difference between Type A and Type B of the SR-20JII?

The back working unit. Type A holds 4 tools there. Type B holds 8 tools and has a Y axis on the unit, so its back tools can be positioned off the spindle centreline. Bar size, spindles, headstock stroke and front tooling are listed once for both types.

02 How fast does the Y2 axis move?

The rapid feed rate row gives 24 m/min for Y2 and 35 m/min for X1, X2, Z1 and Z2. Y2 moves are short, so the lower rate has little effect on cycle time unless a program switches between many back tools.

03 What front tooling does the SR-20JII carry?

There are 6 front turning tools on 12 mm shanks and a 5-spindle sleeve holder with 5 tools facing the front and 5 facing the rear. The table does not list the cross-working driven tools, so ask for the tooling layout if your parts need milling from the front side.

04 Can the SR-20JII run 23 mm bar?

Yes, as an option. Standard maximum machining diameter is 20 mm (25/32 in), and 23 mm (29/32 in) is listed as optional. Order the machine with that option if any of your stock is over 20 mm, and confirm the matching collets and guide bushings.

05 How does the SR-20JII compare with the SR-32J?

The SR-32J is the larger machine: ø32mm (1-1/4in) turning diameter, 4,100 kg, and a spindle of 8,000 rpm rated 7.5 kW continuous. The SR-20JII is listed at 20 mm (25/32 in), 2,750 kg and 10,000 rpm with 2.2 kW continuous. Both use a FANUC 32i-B control.