Star Micronics SK-51 Type A

Est. $250,000 - $400,000 Specs verified 2026-10-03 · starcnc.com Updated 2026-10-03

Image: starcnc.com, Star Micronics

Key Specifications

Max Spindle

5,000 min rpm

Spindle Power

7.5kW (continuous)/11kW (15min.)

max machining diameter

51 mm (2 in)

through spindle bore

52.5 mm (2-1/16 in)

main spindle speed

5,000 RPM

main spindle power

7.5 kW continuous / 11 kW (15 min)

How much does the Star Micronics SK-51 Type A cost?

Estimated price range

Est.$250,000 - $400,000

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 SK-51 Type A is a twin-spindle, twin-turret lathe for bar work up to 51 mm (2 in), with a 52.5 mm (2-1/16 in) through-spindle bore and two 12-station turrets. Main and sub spindle carry the same rating: 5,000 RPM, 7.5 kW continuous and 11 kW on the 15 min rating.

That symmetry is the point of the machine. With equal power on both sides, the second operation can take cuts as heavy as the first, so the work can be divided evenly between the spindles instead of being rationed to suit a weak sub spindle. The bore of 52.5 mm (2-1/16 in) leaves little clearance over 51 mm stock, so bar straightness and feeder alignment deserve attention.

Each turret has 12 stations and a station takes a maximum of 2 tools, on 20 mm (25/32 in) shanks. Maximum drilling capacity is 16 mm (5/8 in). The rapid rates are far apart: 40 m/min on Z, 20 m/min on X and 15 m/min on Y. Long Z moves between the spindles are quick, while Y repositioning is the slow motion in a cycle.

This is a heavy installation for its bar size. Star lists 6,600 kg, a floor space of 2,800 mm W x 2,070 mm D x 2,130 mm H and a 458 L coolant tank, under a FANUC 32i-B control. For scale, the SB-38 is listed at 4,300kg for Ø38mm (1-1/2in) bar, with a 7,000min-1 spindle and the same 7.5kw continuous rating.

Full Specifications

Parameter	Value
Max Machining Diameter	51 mm (2 in)
Through Spindle Bore	52.5 mm (2-1/16 in)
Main Spindle Speed	5,000 RPM
Main Spindle Power	7.5 kW continuous / 11 kW (15 min)
Sub Spindle Speed	5,000 RPM
Sub Spindle Power	7.5 kW continuous / 11 kW (15 min)
Turrets	2 x 12-station (max 2 tools per station)
Max Drilling Capacity	16 mm (5/8 in)
CNC Control	FANUC 32i-B
Coolant Tank	458 L
Machine Weight	6,600kg
Dimensions	2,800 x 2,070 x 2,130 mm
Max Turning Diameter	Ø51mm (2in.)
Max Spindle Speed	5,000 min rpm
Spindle Motor Power	7.5kW (continuous)/11kW (15min.)
Spindle Bore	Ø52.5mm (2-1/16in)
Turret Stations	12
Rapid Traverse X	20m/min
Rapid Traverse Y	15m/min
Rapid Traverse Z	40m/min
Coolant Capacity	458ℓ
Floor Space	2,800mm W x 2,070mm D x 2,130mm H
CNC Control	FANUC 32i-B
Tool Shank Size	20 mm (25/32 in); max. 2 tools per station

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

Strengths & Limitations

Strengths

Main and sub spindle are rated identically: 5,000 RPM, 7.5 kW continuous and 11 kW (15 min)
Two 12-station turrets, each station taking up to 2 tools
52.5 mm (2-1/16 in) through-spindle bore for 51 mm (2 in) bar
40 m/min rapid traverse on Z
458 L coolant tank, a large reserve for long production runs
20 mm (25/32 in) tool shanks, a stiff size for heavier turning cuts

Limitations

Spindle speed tops out at 5,000 RPM on both spindles, which limits surface speed on small diameters and small drills
Maximum drilling capacity is 16 mm (5/8 in), small against the 51 mm (2 in) bar size
Y rapid traverse is 15 m/min and X is 20 m/min, well below the 40 m/min of Z
Weighs 6,600 kg and occupies 2,800 mm W x 2,070 mm D x 2,130 mm H before a bar feeder is added
The table gives no driven-tool speed or power

Best For

Bar parts up to 51 mm (2 in) with heavy cuts on both ends Jobs that balance cycle time across two equal 7.5 kW spindles Work needing many tools on hand: two 12-station turrets with up to 2 tools per station Long runs that benefit from a 458 L coolant tank

Frequently Asked Questions

01 What is the bar capacity of the Star SK-51 Type A?

Maximum machining diameter is 51 mm (2 in), fed through a spindle bore of 52.5 mm (2-1/16 in). The margin between bar and bore is small, so use straight stock and a well-aligned bar feeder when running at the full diameter.

02 Are the main and sub spindles the same?

In the table, yes. Both are listed at 5,000 RPM with 7.5 kW continuous and 11 kW on the 15 min rating. That lets the back-end operation carry as much of the metal removal as the front, which is useful when balancing the two halves of a cycle.

03 How many tools does the SK-51 Type A hold?

It has two turrets of 12 stations each, and Star states a maximum of 2 tools per station. Tool shanks are 20 mm (25/32 in). How many stations are doubled up in practice depends on the holders chosen, so work that out with the tooling list for your parts.

04 How fast are the axes?

Rapid traverse is 20 m/min on X, 15 m/min on Y and 40 m/min on Z. Z is twice as fast as X, which suits a machine that moves parts and turrets along the spindle line. Programs with a lot of Y repositioning will see less benefit.

05 What does the SK-51 Type A need for installation?

Floor space of 2,800 mm W x 2,070 mm D x 2,130 mm H and a foundation for 6,600 kg. The coolant tank holds 458 L. The table does not state the electrical supply, and a bar feeder for 51 mm stock adds to the length, so request the installation drawing.