Haas ST-28Y
Key Specifications
Max Spindle
Tool Capacity
Weight
Spindle Power
max cutting diameter
max cutting length
Overview
The Haas ST-28Y is the first step into Haas's big-bore Y-axis turning center lineup. With a 305 mm (12 in) chuck on an A2-8 spindle nose and 102 mm (4.0 in) bar capacity, it handles workpieces that the ST-25Y and ST-30Y simply cannot swallow. The larger spindle bore opens up through-spindle machining on pipe, tubing, and large-diameter bar stock.
Spindle power jumps to 29.8 kW (40 hp) with a maximum speed of 3,200 RPM. Peak torque sits at 542 Nm (400 ft-lb) at 500 RPM on the standard drive. The optional gearbox pushes that to 1,898 Nm (1,400 ft-lb) at 150 RPM, which puts this machine in serious heavy-turning territory. That kind of torque lets you take aggressive depths of cut in alloy steel, stainless, and cast iron without stalling.
Y-axis travel is 102 mm (4.0 in) total on a 12-station BMT-65 turret with 6,000 RPM live tooling at 3.7 kW (5 hp). C-axis positioning holds plus or minus 0.01 degrees. The milling capability is the same as the ST-25Y and ST-30Y, so you get identical cross-drilling, flat milling, and tapping performance. The larger chuck and spindle bore just expand the range of parts you can hold.
Max cutting diameter is 406 mm (16 in) with a cutting length of 711 mm (28 in). The work envelope suits mid-to-large shaft work, flanges, and components that need both turning and secondary milling operations. At roughly 7,257 kg (16,000 lb), the machine has good thermal mass and stability for the price class.
Priced around $110,000-$140,000 configured, the ST-28Y competes with the Mazak QT-300MSY and Okuma LB3000 EX II-MY. The Japanese machines offer more refinement and tighter tolerances out of the box, but cost $40,000-$60,000 more. For shops that need big-bore Y-axis turning without crossing the $150K threshold, the ST-28Y delivers the capability at a Haas price point. Specs sourced from Haas Automation published data.
Full Specifications
| Parameter | Value |
|---|---|
| Max Cutting Diameter | 406 mm (16 in) |
| Max Cutting Length | 711 mm (28 in) |
| Max Swing Over Front Apron | 838 mm (33 in) |
| Max Swing Over Cross Slide | 559 mm (22 in) |
| Max Spindle Speed | 3,200 RPM |
| Spindle Motor Power | 29.8 kW (40 hp) |
| Spindle Torque | 542 Nm (400 ft-lb) @ 500 RPM |
| Spindle Torque Optional Gearbox | 1,898 Nm (1,400 ft-lb) @ 150 RPM |
| Spindle Nose | A2-8 |
| Spindle Bore | 105 mm (4.13 in) |
| Chuck Size | 305 mm (12 in) |
| Bar Capacity | 102 mm (4.0 in) |
| X Axis Travel | 318 mm (12.5 in) |
| Y Axis Travel | 102 mm (4.0 in) total / ±50.8 mm (±2.0 in) |
| Z Axis Travel | 711 mm (28 in) |
| Rapid Traverse X Y | 12.0 m/min (472 IPM) |
| Rapid Traverse Z | 24.0 m/min (945 IPM) |
| Tool Capacity | 12-station BMT-65 turret |
| Live Tooling Speed | 6,000 RPM |
| Live Tooling Power | 3.7 kW (5 hp) |
| C Axis Positioning | ±0.01° |
| Machine Weight | 7,257 kg (16,000 lb) |
| Coolant Capacity | 208 L (55 gal) |
| CNC Control | Haas Next Generation Control (NGC) |
Specifications sourced from haascnc.com — verified 2026-03-28
Strengths & Limitations
Strengths
- 40 hp spindle with 400 ft-lb of torque handles heavy roughing in steel, stainless, and cast iron without backing off feeds
- 102 mm (4.0 in) bar capacity opens up through-spindle work on pipe, tubing, and large-diameter stock
- Optional gearbox delivers 1,400 ft-lb of torque at 150 RPM for large-diameter interrupted cuts in demanding materials
- 12-inch chuck on A2-8 nose provides secure clamping on bigger workpieces than the ST-25Y or ST-30Y can hold
- BMT-65 turret with 6,000 RPM live tooling and C-axis delivers genuine mill-turn capability
- Same NGC control platform as every Haas machine, keeping operator training and programming consistent
- Priced $40-60K below comparable Mazak QT-300MSY and Okuma LB3000 EX II-MY configurations
Limitations
- 3,200 RPM max spindle speed limits surface speed on small-diameter work and aluminum finishing
- 3.7 kW (5 hp) live tooling motor is the same as smaller ST models, which can feel underpowered on a machine this size
- 16,000 lb machine weight requires solid floor preparation and careful rigging during installation
- No sub-spindle option limits done-in-one capability for parts needing back-working operations
- Resale value depreciates faster than Japanese competitors in the used machine market
Best For
Frequently Asked Questions
01
Base price starts around $110,000. With common options including tailstock, chip conveyor, high-pressure coolant, and bar feeder interface, configured price runs $125,000-$140,000. The optional gearbox adds about $5,000 for 1,400 ft-lb of low-speed torque.
02
The ST-28Y jumps to a 12-inch chuck, A2-8 spindle nose, 4.0-inch bar capacity, and 40 hp spindle versus the ST-25Y's 10-inch chuck, A2-6, 3.0-inch bar, and 30 hp. The ST-28Y also has a longer 28-inch cutting length. It's the machine you pick when your parts outgrow the ST-25Y's work envelope.
03
The Mazak has a more refined control, optional sub-spindle, and generally tighter tolerances out of the box. But it costs $40-60K more configured. The ST-28Y is the value alternative for shops that need big-bore Y-axis turning without crossing the $150K line.
04
Yes. The 102 mm (4.0 in) bar capacity works with the Haas Bar Feeder 12 and compatible third-party magazine bar feeders. The bar feeder interface is a common add-on for unattended production.
05
If you regularly turn large diameters in tough materials like stainless or alloy steel, absolutely. The gearbox pushes torque from 400 ft-lb to 1,400 ft-lb at 150 RPM. For shops primarily running bar stock under 75 mm, the standard drive provides enough torque without the gearbox.
Videos
Haas Automation UK
Haas Automation UK
Haas Automation UK
Pierson Workholding
Haas Automation, Inc.
Community Discussions
Community discussion — Haas has quality gone down? : r/Machinists - Reddit
Community discussion — Is Haas Really That Bad? : r/Machinists - Reddit
Comparison and buying advice — Milling CNC precision & stability - why does Haas suck? : r ...
Community discussion — Haas cnc machine reliability? : r/Machinists - Reddit
Links to community discussions. Summaries are editorial — visit the original thread for full context.
