Haas ST-28Y
Key Specifications
X Travel
Y Travel
Z Travel
Max Spindle
Tool Capacity
Weight
Overview
The Haas ST-28Y is a big-bore turning centre with a Y axis and a sub spindle. The main spindle carries a 305 mm (12.0 in) chuck on an A2-8 nose, with a 117.3 mm (4.62 in) bore and 102 mm (4.00 in) bar capacity. That bore is the specification that defines the machine: pipe, tube and heavy bar pass through the headstock rather than hanging out the back on a support.
Spindle power is 29.8 kW (40.0 hp) with a 3,200 rpm maximum and 576.0 Nm (425.0 ft-lbf) at 325 rpm through a belt drive. High torque at low speed is the correct shape for a 12-inch chuck — the machine is set up to take a heavy cut on large-diameter steel and cast iron, not to spin small parts fast. Maximum part swing is 533 mm (21.0 in), but maximum cutting diameter is 298 mm (11.75 in) with the BMT65 turret fitted, over 572 mm (22.5 in) of cutting length. That gap between swing and cutting diameter is turret clearance, and it is the detail most likely to catch someone out when quoting large flange work.
Y-axis travel is ±51 mm (±2.0 in) about the centreline, with 239 mm (9.40 in) on X and 572 mm (22.50 in) on Z. That is enough Y for off-centre milling, flats, slots and bolt circles, not enough to treat the lathe as a machining centre. The 12-station BMT65 turret drives live tooling to 4,000 rpm, and the C axis positions to ±0.01° with 3.7 kW (5.0 hp), 60 rpm maximum, and a 339 Nm (250 ft-lbf) brake holding torque on a 353 mm (13.9 in) brake disc. That brake figure is what actually limits how aggressively you can mill off-centre.
The sub spindle takes 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, so back-end work happens in-cycle. Rapids are 12.0 m/min (472 ipm) on X and Y and 24.0 m/min (945 ipm) on Z, with 102.0 mm (4.00 in) of rear clearance for boring bars.
The machine weighs 4,926 kg (10,860 lb), holds 208 L (55 gal) of coolant and runs on 220 VAC three-phase at 70 A or 440 VAC at 35 A. It suits shops turning large-diameter or tubular stock that also need secondary milling — oilfield components, flanges, couplings and heavy fittings.
Full Specifications
| Parameter | Value |
|---|---|
| Chuck Size | 305 mm (12.0 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 | 102 mm (4.00 in) |
| X-Axis Travel | 239 mm (9.40 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 | A2-8 |
| Spindle Motor Power | 29.8 kW (40.0 hp) |
| Max Spindle Speed | 3,200 rpm |
| Spindle Torque Max | 576.0 Nm @ 325 rpm (425.0 ft-lbf @ 325 rpm) |
| Spindle Bore | 117.3 mm (4.62 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 | 4,926 kg (10,860 lb) |
Specifications sourced from haascnc.com — verified 2026-08-09
Strengths & Limitations
Strengths
- A 117.3 mm (4.62 in) spindle bore with 102 mm (4.00 in) bar capacity lets pipe, tube and heavy bar pass through the headstock rather than hang out the back on a support
- 576.0 Nm (425.0 ft-lbf) at 325 rpm from a 29.8 kW (40.0 hp) spindle is the right shape for a 305 mm (12.0 in) chuck - heavy cuts on large-diameter steel and cast iron
- The sub spindle carries a 135 mm (5.3 in) chuck on an A2-5 nose and runs to 6,000 rpm, so back-end work happens in-cycle
- Y travel of ±51 mm (±2.0 in) with a C axis positioning to ±0.01° gives real off-centre milling - flats, slots and bolt circles - beyond what a plain turret can do
- The 12-station BMT65 turret drives live tooling to 4,000 rpm and leaves 102.0 mm (4.00 in) of rear clearance for boring bars
- Axis thrust of 22,686 N (5,100 lbf) on Z and 18,238 N (4,100 lbf) on X supports the heavy feeds the spindle torque invites
Limitations
- Maximum cutting diameter is 298 mm (11.75 in) with the BMT65 turret fitted, well under the 533 mm (21.0 in) maximum part swing - that turret-clearance gap catches people out when quoting large flange work
- Spindle speed tops out at 3,200 rpm, which limits surface speed on small-diameter work and aluminium finishing
- The C-axis drive is 3.7 kW (5.0 hp) with a 339 Nm (250 ft-lbf) brake, and that brake figure - not the live-tool speed - is what really limits how aggressively you can mill off-centre
- Y travel is only ±51 mm (±2.0 in) about the centreline: enough for off-centre features, not enough to treat the lathe as a machining centre
- Sub-spindle bore is 38.1 mm (1.50 in) against 117.3 mm on the main spindle, so back-end work is confined to much smaller stock
Best For
Frequently Asked Questions
01
Maximum part swing is 533 mm (21.0 in), but maximum cutting diameter is 298 mm (11.75 in) with the BMT65 turret fitted, over 572 mm (22.5 in) of cutting length. The gap between those two figures is turret clearance, and it is the detail most likely to catch someone out when quoting large flange work. Quote against the cutting diameter, not the swing.
02
The main spindle bore is 117.3 mm (4.62 in), with a rated bar capacity of 102 mm (4.00 in), on an A2-8 nose carrying a 305 mm (12.0 in) chuck. That bore is the specification that defines the machine: pipe, tube and heavy bar pass through the headstock rather than hanging out the back on a support.
03
Y travel is ±51 mm (±2.0 in) about the centreline, and the 12-station BMT65 turret drives live tooling to 4,000 rpm. The C axis positions to ±0.01° with a 3.7 kW (5.0 hp) drive, 60 rpm maximum, and a 339 Nm (250 ft-lbf) brake on a 353 mm (13.9 in) disc. That brake torque is the real limit on how hard you can mill off-centre, not the live-tool speed.
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, so back-end work happens in-cycle rather than as a second setup. Note the bore difference - 38.1 mm against 117.3 mm on the main spindle - which confines the second operation to much smaller stock than the first.
05
Either 220 VAC three-phase at 70 A or 440 VAC three-phase at 35 A, plus 113.0 L/min of air at 6.9 bar (4 scfm at 100 psi) with a 5.5 bar (80 psi) minimum supply pressure. The machine weighs 4,926 kg (10,860 lb) and holds 208 L (55 gal) of coolant.
Videos
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