Haas ST-40S
Key Specifications
Max Spindle
Spindle Taper
Tool Capacity
Spindle Power
max part swing
max cutting diameter
Overview
The Haas ST-40S is the large through-bore variant of the ST-40 platform, featuring a wider spindle bore than the standard ST-40 while maintaining the same heavy castings, 29.8 kW (40 hp) spindle, and 381 mm (15 in) chuck. The S designation indicates a larger spindle bore configuration optimized for shops running oversized bar stock or tubular components through the spindle.
The spindle drives through a 2-speed gearbox, producing 1,898 Nm (1,400 ft-lb) of torque at 150 RPM with a max speed of 2,400 RPM. An optional XP high-performance spindle bumps output to 41.0 kW (55 hp) and 2,847 Nm (2,100 ft-lb). The max cutting envelope is 762 mm (30 in) diameter by 1,118 mm (44 in) length with the BOT turret.
The large through-bore focus makes the ST-40S the choice for shops that need more bar capacity than the standard ST-40 4.0-inch bore but do not need to step up to the ST-45 7.0-inch bore. It handles larger-diameter tubular stock, hollow components, and pipe fittings that pass through the spindle for efficient loading and unloading.
The 12-station BOT turret is standard, with optional BMT75 turret available for live tooling. Axis travels are 508 mm (20 in) in X and 1,118 mm (44 in) in Z with rapids at 18.0 m/min on both axes. The NGC control provides the same familiar programming environment as every other Haas machine.
At $185,000-$255,000 configured, the ST-40S fills the gap between the ST-40 and ST-45 for shops that need more through-bore capacity without the full ST-45 large-bore premium. Specs derived from Haas Automation published ST-40 data.
Full Specifications
| Parameter | Value |
|---|---|
| Max Part Swing | 35.5 in |
| Max Cutting Diameter | 27.50 in |
| Max Cutting Length | 28.0 in |
| Chuck Size | 15.0 in |
| Bar Capacity | 4.00 in |
| Spindle Nose | A2-8 |
| Spindle Bore | 4.62 in |
| Max Spindle Speed | 2,400 RPM |
| Spindle Motor Power | 40.0 hp |
| Spindle Torque | 1,898 Nm (1,400 ft-lb) @ 150 RPM |
| Spindle Drive | 2-Speed Gearbox |
| Xp Spindle Power | 41.0 kW (55 hp) |
| Xp Spindle Torque | 2,847 Nm (2,100 ft-lb) @ 150 RPM |
| X Axis Travel | 508 mm (20 in) |
| Z Axis Travel | 1,118 mm (44 in) |
| Rapid Traverse X | 18.0 m/min (710 ipm) |
| Rapid Traverse Z | 18.0 m/min (710 ipm) |
| Max Thrust X | 5500 lbf |
| Max Thrust Z | 9000 lbf |
| Tool Capacity | 12-Station BOT |
| Tailstock Taper | MT5 |
| Tailstock Travel | 1,067 mm (42 in) |
| Coolant Capacity | 95 gal |
| Machine Weight | 20400 lb |
| CNC Control | Haas Next Generation Control (NGC) |
| Capacities | S.A.E |
| Travels | S.A.E |
| X Axis | 20.00 in |
| Z Axis | 28.00 in |
| Feedrates | S.A.E |
| Rapids On X | 710 ipm |
| Rapids On Z | 710 ipm |
| Axis Motors | S.A.E |
| Spindle | S.A.E |
| Spindle Taper | A2-8 |
| Drive System | 2-Speed Gearbox |
| Max Rating | 55.0 hp |
| Max Speed | 2400 rpm |
| Max Torque | 2100.0 ft-lbf @ 150 rpm |
| Xp Option | S.A.E |
| Input Ac Voltage Low | 220 VAC |
| Full Load Amps Low | 70 A |
| Input Ac Voltage High | 440 VAC |
| Full Load Amps High | 35 A |
| Tailstock | S.A.E |
| Taper | MT5 |
| Travel | 26.0 in |
| Max Thrust | 3,000 lbf |
| Min Thrust | 200 lbf |
| Turret | S.A.E |
| Od Vs Id Tools | Any Combination (will vary with turret) |
| Boring Bar Rear Clearance | 4.50 in |
| Tooling | BOT |
| 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 |
| Dimensions Shipping | S.A.E |
| Domestic Pallet | 216.5 in x 94.5 in x 116.0 in |
| Export Crate | 216.5 in x 95.0 in x 120.0 in |
Specifications sourced from haascnc.com — verified 2026-03-28
Strengths & Limitations
Strengths
- Larger through-bore than the standard ST-40 enables processing of oversized bar stock and tubular components
- 40 hp spindle with 1,400 ft-lb of torque through a 2-speed gearbox for heavy material removal
- Optional XP spindle upgrade to 55 hp and 2,100 ft-lb for aggressive roughing in tough alloys
- Same proven ST-40 castings and cutting envelope with increased through-bore capacity
- Maintains 2,400 RPM max spindle speed for better surface speed than the larger-bore ST-45 at 1,400 RPM
- At $185-255K, costs less than the ST-45 while providing more bore capacity than the standard ST-40
Limitations
- Through-bore is still smaller than the ST-45 7.0-inch bore for shops needing maximum tube capacity
- 2,400 RPM max spindle speed limits surface speed on smaller-diameter aluminum work
- Machine weight of 10,206 kg requires reinforced flooring and professional rigging
- No Y-axis in the base ST-40S configuration — add Y-axis capability requires stepping to ST-40SY
Best For
Frequently Asked Questions
01
Base price starts around $185,000. Configured with tailstock, XP spindle, chip conveyor, and high-pressure coolant, expect $220,000-$255,000. The large through-bore premium over the standard ST-40 is approximately $10,000.
02
The ST-40S has a larger spindle bore for passing oversized bar stock and tubular components. The standard ST-40 has a 117.3 mm (4.62 in) bore. Both share the same castings, spindle power, chuck size, and cutting envelope. Choose the ST-40S when your bar stock or tubular work exceeds the standard bore.
03
The ST-45 has a 178 mm (7.0 in) bore with A2-11 nose and 18-inch chuck, running at 1,400 RPM max. The ST-40S offers a mid-range bore with 2,400 RPM max speed on an A2-8 nose with 15-inch chuck. Choose the ST-45 for maximum bore capacity; choose the ST-40S when you need more bore than the ST-40 but want higher RPM.
04
Yes, with the optional BMT75 turret and C-axis. The BMT75 supports 4,000 RPM live tooling for cross-drilling, milling, and tapping. However, the base ST-40S uses a 12-station BOT turret for turning operations only.
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