Haas ST-25Y
Key Specifications
X Travel
Y Travel
Z Travel
Max Spindle
Tool Capacity
Weight
Overview
The Haas ST-25Y is a Y-axis turning center with a sub-spindle, sitting in the middle of the Haas ST lineup. A 254 mm (10.0 in) chuck on an A2-6 spindle nose with an 88.9 mm (3.50 in) bore gives 76 mm (3.00 in) bar capacity, which covers most production bar stock without moving up to a big-bore machine. Maximum part swing is 533 mm (21.0 in), with 298 mm (11.75 in) of cutting diameter using the BMT65 turret and 572 mm (22.5 in) of cutting length.
The spindle is rated 22.4 kW (30.0 hp) with 407.0 Nm (300.0 ft-lbf) at 500 rpm, topping out at 3,400 rpm. The torque curve is the useful part of that specification: 300 ft-lbf low down means heavy roughing passes in steel and stainless without the spindle pulling down on interrupted cuts. The 3,400 rpm ceiling is the corresponding trade — small-diameter work at high surface speed is not this machine's strength.
Y travel is ±51 mm (±2.0 in) about centerline, driven at up to 10,231 N (2,300 lbf) of thrust. That is enough offset to mill flats, hex forms, slots and off-center holes on a turned part, but not enough to treat the lathe as a milling machine. Live tooling runs to 4,000 rpm on the 12-station BMT65 turret, with C-axis positioning to ±0.01° backed by a 353 mm (13.9 in) brake holding 339 Nm (250 ft-lbf) — the brake is what makes milling on a lathe rigid enough to hold a finish, since it locks the spindle rather than asking the C-axis drive to resist cutting load.
The sub-spindle carries a 135 mm (5.3 in) chuck on an A2-5 nose with a 38.1 mm (1.50 in) bore, running to 6,000 rpm. Note it is a distinctly smaller spindle than the main: back-end work should be planned as finishing and light cutting, not as a second roughing operation.
Rapids are 12.0 m/min (472 ipm) in X and Y and 24.0 m/min (945 ipm) in Z. The machine weighs 5,580 kg (12,300 lb) and needs 220 VAC at 70 A or 440 VAC at 35 A, with a 208 L (55 gal) coolant tank. It suits job shops and component producers running bar and chuck work that needs milled features without a second-operation VMC.
Full Specifications
| Parameter | Value |
|---|---|
| Chuck Size | 254 mm (10.0 in) |
| Max Part Swing | 533 mm (21.0 in) |
| Max Cutting Diameter | 298 mm (11.75 in) with BMT65 turret |
| Max Cutting Length | 572 mm (22.5 in) |
| Bar Capacity | 76 mm (3.00 in) |
| X-Axis Travel | 213 mm (8.40 in) |
| Y-Axis Travel | ±51 mm (±2.0 in) |
| Z-Axis Travel | 572 mm (22.50 in) |
| Rapid Traverse X | 12.0 m/min (472 ipm) |
| Rapid Traverse Y | 12.0 m/min (472 ipm) |
| Rapid Traverse Z | 24.0 m/min (945 ipm) |
| Max Thrust X | 18,238 N (4,100 lbf) |
| Max Thrust Y | 10,231 N (2,300 lbf) |
| Max Thrust Z | 22,686 N (5,100 lbf) |
| Spindle Nose | A2-6 |
| Spindle Motor Power | 22.4 kW (30.0 hp) |
| Max Spindle Speed | 3,400 rpm |
| Spindle Torque Max | 407.0 Nm @ 500 rpm (300.0 ft-lbf @ 500 rpm) |
| Spindle Bore | 88.9 mm (3.50 in) |
| Spindle Drive | Direct Speed, Belt Drive |
| C Axis Power | 3.7 kW (5.0 hp) |
| C Axis Speed Max | 60 rpm |
| C Axis Positioning | ±0.01° |
| C Axis Brake Diameter | 353 mm (13.9 in) |
| C Axis Brake Holding Torque | 339 Nm (250 ft-lbf) |
| Sub Spindle Chuck Size | 135 mm (5.3 in) |
| Sub Spindle Nose | A2-5 |
| Sub Spindle Speed Max | 6,000 rpm |
| Sub Spindle Bore | 38.1 mm (1.50 in) |
| Tool Capacity | 12 Stations |
| Boring Bar Rear Clearance | 102.0 mm (4.00 in) |
| Live Tooling Speed | 4,000 rpm |
| Live Tooling | BMT65 |
| Coolant Capacity | 208 L (55 gal) |
| Air Required | 113.0 L/min @ 6.9 bar (4 scfm @ 100 psi) |
| Air Pressure Min | 5.5 bar (80 psi) |
| Electrical Low | 220 VAC 3-phase, 70 A |
| Electrical High | 440 VAC 3-phase, 35 A |
| Machine Weight | 5,580 kg (12,300 lb) |
Specifications sourced from haascnc.com — verified 2026-08-09
Strengths & Limitations
Strengths
- 407.0 Nm (300.0 ft-lbf) at 500 rpm from a 22.4 kW (30.0 hp) spindle supports heavy roughing passes in steel and stainless without pulling down on interrupted cuts
- A2-6 spindle nose with an 88.9 mm (3.50 in) bore gives 76 mm (3.00 in) bar capacity, covering most production bar stock without moving to a big-bore machine
- ±51 mm (±2.0 in) of Y travel at up to 10,231 N (2,300 lbf) of thrust mills flats, hex forms, slots and off-center holes on a turned part
- C-axis positioning to ±0.01° backed by a 353 mm (13.9 in) brake holding 339 Nm (250 ft-lbf) — the brake locks the spindle rather than asking the C-axis drive to resist cutting load
- Sub-spindle with a 135 mm (5.3 in) chuck running to 6,000 rpm completes the back end without a second setup
- 12-station BMT65 turret with live tooling to 4,000 rpm covers turning and milling from one carrier
Limitations
- The 3,400 rpm spindle ceiling means small-diameter work at high surface speed is not this machine's strength
- The sub-spindle is distinctly smaller than the main — a 135 mm (5.3 in) chuck on an A2-5 nose with a 38.1 mm (1.50 in) bore — so back-end work should be planned as finishing and light cutting
- ±51 mm of Y offset is enough for milled features on a turned part but not enough to treat the lathe as a milling machine
- 12 turret stations fill quickly once a job needs a full turning set plus live tools
- Maximum cutting diameter is 298 mm (11.75 in) with the BMT65 turret, well inside the 533 mm (21.0 in) part swing
Best For
Frequently Asked Questions
01
The chuck is 254 mm (10.0 in) on an A2-6 nose, with maximum part swing of 533 mm (21.0 in). Usable cutting envelope is 298 mm (11.75 in) in diameter with the BMT65 turret by 572 mm (22.5 in) long. The 88.9 mm (3.50 in) spindle bore gives 76 mm (3.00 in) bar capacity.
02
It handles milled features on turned parts well. Y travel is ±51 mm (±2.0 in) about centerline at up to 10,231 N (2,300 lbf) of thrust, with live tooling to 4,000 rpm on the BMT65 turret. That covers flats, hex forms, slots and off-center holes. It is not a substitute for a machining center — the Y offset is a feature-cutting budget, not a prismatic-machining one.
03
C-axis positioning is ±0.01° with a 3.7 kW (5.0 hp) drive and a 60 rpm maximum. The important part is the brake: 353 mm (13.9 in) in diameter holding 339 Nm (250 ft-lbf). It locks the spindle during milling rather than relying on the C-axis drive to resist cutting load, which is what allows a milled feature to hold a finish.
04
It carries a 135 mm (5.3 in) chuck on an A2-5 nose with a 38.1 mm (1.50 in) bore and runs to 6,000 rpm. It is a noticeably smaller spindle than the 254 mm main, so back-end operations should be scoped as finishing and light cutting rather than a second roughing pass.
05
The machine weighs 5,580 kg (12,300 lb) and takes 220 VAC 3-phase at 70 A or 440 VAC 3-phase at 35 A. Air demand is 113.0 L/min at 6.9 bar (4 scfm at 100 psi) with a 5.5 bar (80 psi) minimum, and the coolant tank holds 208 L (55 gal).
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Community Discussions
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Community discussion — Haas has quality gone down? : r/Machinists - Reddit
Community discussion — Is Haas Really That Bad? : r/Machinists - Reddit
Links to community discussions. Summaries are editorial — visit the original thread for full context.
