Haas ST-55SY

$420,000 - $500,000 Updated 2026-03-19

Key Specifications

Max Spindle

1,000 RPM

Spindle Taper

A1-20 Front & Rear

Tool Capacity

12 Stations

Spindle Power

55.0 hp

swing over front apron

876 mm (34.5 in)

swing over cross slide

648 mm (25.5 in)

Overview

The Haas ST-55SY is the sub-spindle Y-axis variant of the largest turning center in the Haas lineup. With a 318 mm (12.5 in) spindle bore, A1-20 spindle nose, and 41.0 kW (55 hp) spindle producing 5,762 Nm (4,250 ft-lb) of torque, the ST-55SY adds sub-spindle back-working and Y-axis milling to the massive ST-55 platform for complete done-in-one processing of the biggest parts Haas can handle.

The main spindle drives through a 2-speed gearbox at a max speed of 1,000 RPM. The 5,762 Nm of torque at 30 RPM reflects this machine focus on heavy material removal at low speed rather than high-RPM finishing. The cutting envelope is 648 mm (25.5 in) diameter by 2,032 mm (80 in) length with the standard long bed.

The sub-spindle enables part pickup, back-working, and cutoff, allowing complete processing of both ends without rechucking. On components like large valve bodies, pipe fittings, and heavy couplings, the sub-spindle maintains concentricity between features machined on opposite faces that would otherwise require multiple setups.

The BMT75 turret provides live tooling at 4,000 RPM with 5.6 kW (7.5 hp). Y-axis travel of 102 mm (4.0 in) total enables cross-drilling, milling flats, bolt patterns, and off-center features. C-axis positioning resolves to 0.01 degrees. The combination of massive bore, sub-spindle, and Y-axis makes this the most feature-rich turning center in the Haas catalog.

At $420,000-$500,000 configured, the ST-55SY is the flagship of the Haas turning center line. It targets oil and gas, power generation, mining, and heavy equipment manufacturers that need complete processing of the largest parts with milled features on both ends. Specs derived from Haas Automation published ST-55 and ST-40SY data.

Full Specifications

Parameter	Value
Swing Over Front Apron	876 mm (34.5 in)
Swing Over Cross Slide	648 mm (25.5 in)
Max Cutting Diameter	27.50 in
Max Cutting Length	44.0 in
Bar Capacity	318 mm (12.5 in)
Spindle Nose	A1-20 Front & Rear
Spindle Bore	12.50 in
Max Spindle Speed	1,000 RPM
Spindle Motor Power	55.0 hp
Spindle Torque	5,762 Nm (4,250 ft-lb) @ 30 RPM
Spindle Drive	2-Speed Gearbox
Sub Spindle	Yes
X Axis Travel	432 mm (17 in)
Y Axis Travel	102 mm (4.0 in) total / ±50.8 mm (±2.0 in)
Z Axis Travel	2,032 mm (80 in)
Rapid Traverse X	18.0 m/min (710 ipm)
Rapid Traverse Z	8.1 m/min (320 ipm)
Tool Capacity	12 Stations
Live Tooling Speed	4,000 RPM
Live Tooling Power	5.6 kW (7.5 hp)
C Axis Positioning	±0.01°
Coolant Capacity	95 gal
Machine Weight	15,422 kg (34,000 lb)
CNC Control	Haas Next Generation Control (NGC)
Capacities	S.A.E
Max Part Swing	35.5 in
Travels	S.A.E
X Axis	20.00 in
Y Axis	± 3.0 in
Z Axis	44.00 in
Feedrates	S.A.E
Rapids On X	472 ipm
Rapids On Y	472 ipm
Rapids On Z	710 ipm
Axis Motors	S.A.E
Max Thrust X	5500 lbf
Max Thrust Y	2300 lbf
Max Thrust Z	9000 lbf
Spindle	S.A.E
Spindle Taper	A1-20 Front & Rear
Drive System	2-Speed Gearbox
Max Rating	5.0 hp
Max Speed	4000 rpm
Max Torque	4250.0 ft-lbf @ 30 rpm
Main Spindle C Axis	S.A.E
Positioning	0.01 °
Brake Holding Torque	450 ft-lbf
Control Type	Interpolated Motion and Positioning
Tailstock	S.A.E
Taper	MT6
Travel	42.0 in
Max Thrust	3,000 lbf
Min Thrust	200 lbf
Turret	S.A.E
Od Vs Id Tools	Any Combination (will vary with turret)
Tooling	BMT75
Live Tooling	S.A.E
General	S.A.E
Air Requirements	S.A.E
Air Required	4 scfm @ 100 psi
Inline Air Hose	3/8 in
Coupler	3/8 in
Air Pressure Min	80 psi
Electrical Specification	S.A.E
Input Ac Voltage Low	220 VAC
Full Load Amps Low	105 A
Input Ac Voltage High	440 VAC
Full Load Amps High	53 A

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

Strengths & Limitations

Strengths

12.5-inch bore with sub-spindle and Y-axis enables complete done-in-one processing of the largest parts Haas can turn
55 hp spindle producing 4,250 ft-lb of torque at 30 RPM delivers massive material removal capability
Sub-spindle maintains concentricity between front and back features on large workpieces
BMT75 turret with 7.5 hp live tooling and Y-axis provides mill-turn capability on the largest platform
80-inch Z-travel handles extended tubular components, long shafts, and heavy pipe work
Complete part processing eliminates multiple setups and handling of very heavy workpieces

Limitations

1,000 RPM max spindle speed severely limits surface speed — this machine is for large, heavy parts only
Z-axis rapids at 8.1 m/min (320 ipm) are slow, increasing non-cutting time on long traverses
At $420-500K, this is the most expensive turning center Haas builds
Machine weight of 15,422 kg requires heavy-duty foundation, floor reinforcement, and specialized rigging

Best For

Oil and gas manufacturers requiring complete processing of large-bore pipe, casing, and couplings with milled features Power generation shops machining large rotors, shafts, and housings with features on both ends Mining and heavy equipment manufacturers producing large components with cross-holes and bolt patterns Shops that need to eliminate multiple setups on very large, heavy workpieces to reduce handling risk Heavy industrial facilities requiring the most capable done-in-one turning center available from Haas

Frequently Asked Questions

01 What does a new Haas ST-55SY cost?

Base price starts around $420,000. Configured with chip conveyor, high-pressure coolant, and additional tooling, expect $460,000-$500,000. The sub-spindle and Y-axis add approximately $65,000-$75,000 over the base ST-55.

02 What is the difference between the ST-55SY and the ST-55Y?

The ST-55SY adds a sub-spindle for part pickup and back-working. The ST-55Y uses a tailstock for part support. Choose the ST-55SY when your parts need machining on both ends and you want to eliminate rechucking operations on these very large, heavy workpieces.

03 Can the ST-55SY replace multiple machines?

For parts that need turning, milling features, and back-working on both ends, yes. The ST-55SY eliminates the need for a separate second-op lathe and potentially a VMC for cross-drilling and milling. On very large parts where handling is expensive and risky, consolidating operations into one machine delivers significant time and safety benefits.

04 What foundation does the ST-55SY require?

At 34,000 lb (15,422 kg), the ST-55SY requires a minimum 12-inch reinforced concrete slab with heavy rebar. A structural engineer should evaluate the floor and foundation before purchase. Professional rigging with overhead crane capacity is essential for installation.