Okuma GP-57N

$280,000 - $400,000 Updated 2026-03-13

Key Specifications

X Travel

305 mm (12.01 in)

Z Travel

1,050 mm (41.34 in)

max grinding diameter

500 mm (19.7 in)

distance between centers

2,150, 2,650, or 3,150

grinding wheel size

510 x 50 mm (20.1 x 2.0 in)

wheel speed max

45 m/s (8,858 sfm)

Overview

The Okuma GP-57N is a mid-range CNC universal cylindrical grinder from Okuma's N series, stepping up to a 500 mm (19.7 in) maximum grinding diameter with 1,000 mm (39.4 in) between centers. The combination of larger diameter capacity and longer center distance compared to the GP-47N makes the GP-57N suitable for a wider range of shaft-type and disc-type components requiring universal grinding operations.

The swivel wheelhead with programmable angular positioning provides OD cylindrical grinding, shoulder grinding, angular plunge grinding, and taper grinding without table swivel. The grinding wheel is 510 x 50 mm (20.1 x 2.0 in) with a maximum peripheral speed of 45 m/s (8,858 sfm). The larger wheel diameter compared to the GP-47N provides more grinding surface and longer intervals between dressings. The wheel spindle uses hydrodynamic bearings.

The X-axis (infeed) travel is 305 mm (12.01 in) with a minimum feed increment of 0.0001 mm (0.000004 in). The Z-axis (traverse) travel is 1,050 mm (41.34 in). Rapid traverse rates are 10 m/min (394 ipm) on X and 15 m/min (591 ipm) on Z. The headstock provides workpiece rotation from 10 to 350 RPM with an MT5 center.

The 1,000 mm between centers accommodates long shafts with multiple grinding features spaced along the workpiece length. The programmable wheelhead swivel allows the control to automatically reposition the wheel angle between grinding operations on different features, enabling complex multi-feature grinding in a single setup. Gap elimination, in-process gauging, and automatic wheel dressing are standard features.

The optional ID grinding spindle attachment adds internal grinding capability for parts requiring combined OD, ID, and face grinding. This is particularly valuable for medium-sized bearing rings and similar components where all ground surfaces need to be concentric.

Machine weight is approximately 9,000 kg (19,842 lb). Floor space runs approximately 5,000 x 2,800 mm (197 x 110 in). New pricing typically ranges from $280,000-$400,000. The GP-57N competes with Studer S41, Kellenberger KEL 1000, and Toyoda GL6Pi for universal cylindrical grinding on larger workpieces.

Full Specifications

Parameter	Value
Max Grinding Diameter	500 mm (19.7 in)
Distance Between Centers	2,150, 2,650, or 3,150
Grinding Wheel Size	510 x 50 mm (20.1 x 2.0 in)
Wheel Speed Max	45 m/s (8,858 sfm)
Wheelhead Swivel	Programmable angular positioning
X-Axis Travel	305 mm (12.01 in)
Z-Axis Travel	1,050 mm (41.34 in)
Min Feed Increment	0.0001 mm (0.000004 in)
Rapid Traverse X	10 m/min (394 ipm)
Rapid Traverse Z	15 m/min (591 ipm)
Workhead Speed	10 - 350 RPM
Workhead Center	MT5
Id Grinding Spindle	Optional attachment
Machine Weight	9,000 kg (19,842 lb)
Floor Space	5,000 x 2,800 mm (197 x 110 in)
CNC Control	Okuma OSP-P300G
Max Grinding Dia	Ø550
Grinding Wheel Odxid	Ø760 × Ø304.8
Max Grinding Wheel Width	130
Rapid Traversex	12
Rapid Traversez	10
Wheel Spindle Motor	15
Okuma Global Repair Center	Charlotte, North Carolina
Inches	Metric

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

Strengths & Limitations

Strengths

500 mm grinding diameter is the largest in the N series, handling large-diameter components including large gear blanks, pump housings, and turbine components
1,000 mm between centers accommodates long shafts with multiple grinding features spaced along the workpiece length
Programmable swivel wheelhead automatically repositions between OD, shoulder, and angular grinding operations within a single program
510 mm grinding wheel with 305 mm X-axis travel provides the reach and surface area for efficient grinding on large-diameter workpieces
Optional ID grinding attachment creates a true universal grinder for OD/ID/face work on medium-sized bearing rings and similar components
9,000 kg machine mass ensures stable, vibration-free grinding even on heavy, large-diameter workpieces

Limitations

5,000 x 2,800 mm footprint is substantial, requiring dedicated floor space with appropriate foundation support for the 9,000 kg machine
50 mm wheel width is narrower than the GA-F series' 75 mm, reducing material removal rate compared to dedicated OD plunge grinders
350 RPM maximum headstock speed limits surface speed on very small diameters; the machine is optimized for larger workpieces
Price of $280,000-$400,000 represents a significant investment for a single grinder, requiring justification through multi-operation consolidation
Swivel wheelhead mechanism adds complexity and requires periodic calibration to maintain angular positioning accuracy

Best For

Heavy equipment manufacturers grinding large pump shafts, hydraulic cylinder components, and gear blanks requiring both OD and shoulder grinding on parts up to 500 mm diameter Power generation shops grinding large turbine shaft journals and bearing seats with both cylindrical and angular features across long shaft lengths Aerospace manufacturers grinding large landing gear components, bearing housings, and structural shafts requiring universal grinding capability Large bearing manufacturers grinding complete bearing rings in the 200-500 mm diameter range with OD, face, and optional ID operations on one machine Job shops serving heavy industry where a single versatile grinder replaces dedicated OD, angular, and face grinding machines

Frequently Asked Questions

01 What does an Okuma GP-57N cost?

New pricing ranges from $280,000-$400,000 depending on wheelhead configuration, ID grinding attachment, in-process gauging, and automation options. The ID grinding attachment and multi-position gauging add significantly to the base price but enable consolidation of multiple grinding operations.

02 How does the GP-57N compare to the GP-47N?

The GP-57N offers 500 mm vs 400 mm grinding diameter, 1,000 mm vs 500 mm between centers, a larger 510 mm grinding wheel vs 455 mm, and more X-axis travel at 305 mm vs 275 mm. It's a substantially larger machine for substantially larger workpieces. Choose the GP-47N for compact parts under 400 mm diameter.

03 Can the GP-57N replace a dedicated OD and ID grinder?

For job shop and mixed-production environments, yes. The swivel wheelhead handles OD and angular grinding, and the optional ID attachment adds bore grinding. For high-volume production where OD and ID grinding run continuously, dedicated machines are more productive. The GP-57N excels when versatility and setup reduction matter more than maximum throughput.

04 What's the maximum workpiece weight the GP-57N can handle?

Workpiece weight capacity depends on the specific headstock and tailstock configuration. The 9,000 kg machine mass and MT5 centers support heavy shaft-type workpieces. For very heavy parts, additional workpiece support via steady rests and drive dogs is recommended. Consult Okuma for the maximum weight specification for your specific grinding application.