Okuma GP-GA-47FII

$260,000 - $350,000 Updated 2026-03-13

Key Specifications

X Travel

305 mm (12.01 in)

Z Travel

1,050 mm (41.34 in)

Rapid Traverse

max grinding diameter

400 mm (15.7 in)

distance between centers

350 / 650 / 1,000 / 1,500

grinding wheel size

510 x 75 mm (20.1 x 3.0 in)

Overview

The Okuma GP-GA-47FII is the largest machine in Okuma's GA-F series, combining the 400 mm (15.7 in) maximum grinding diameter with an extended 1,000 mm (39.4 in) distance between centers. This machine handles the most demanding cylindrical grinding work in the GA lineup: long, large-diameter shafts found in power generation, heavy equipment, marine, and aerospace applications.

The grinding wheel is 510 x 75 mm (20.1 x 3.0 in) with a maximum peripheral speed of 45 m/s (8,858 sfm). The longer table provides positions for steady rest support at multiple locations along the workpiece, critical for maintaining roundness on long shafts with large diameters. The wheel spindle uses hydrodynamic bearings and the increased spindle motor power handles the material removal demands of large-diameter grinding.

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 and heavy-duty workpiece driving options.

The FII generation OSP-P300G control manages complex multi-journal grinding sequences across the full 1,000 mm workpiece length. Each plunge position can have independently programmed grinding parameters, spark-out times, and in-process gauge targets. Gap elimination operates at each position, minimizing air grinding time on multi-journal shafts. The table swivels +/- 6 degrees for long taper grinding.

Machine weight is approximately 8,500 kg (18,739 lb). Floor space runs approximately 4,800 x 2,600 mm (189 x 102 in). New pricing typically ranges from $260,000-$350,000. The GP-GA-47FII represents the top of Okuma's cylindrical grinding range and competes with Studer S41, WaldrichSiegen, and large Toyoda grinders for heavy-duty precision cylindrical grinding.

Full Specifications

Parameter	Value
Max Grinding Diameter	400 mm (15.7 in)
Distance Between Centers	350 / 650 / 1,000 / 1,500
Grinding Wheel Size	510 x 75 mm (20.1 x 3.0 in)
Wheel Speed Max	45 m/s (8,858 sfm)
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
Swivel Angle	+/- 6°
Machine Weight	8,500 kg (18,739 lb)
Floor Space	4,800 x 2,600 mm (189 x 102 in)
CNC Control	Okuma OSP-P300G
Max Grinding Dia	Ø400
Grinding Wheel Odxid	Ø760x304.8
Max Grinding Wheel Width	150
Rapid Traverse Rate	16
Wheel Spindle Motor	15 [22]
Okuma Global Repair Center	Charlotte, North Carolina
Inches	Metric

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

Strengths & Limitations

Strengths

Combines 400 mm grinding diameter with 1,000 mm between centers, the largest capacity in Okuma's GA series for long, large-diameter shaft grinding
1,050 mm Z-axis traverse enables full-length traverse grinding and multi-journal plunge grinding across the entire workpiece length
Multiple steady rest positions along the longer table prevent deflection on long shafts with unfavorable length-to-diameter ratios
305 mm X-axis travel accommodates the approach and clearance needs of the full 400 mm workpiece diameter range
FII generation multi-journal grinding programs with independent parameters at each position optimize cycle time on complex shafts
8,500 kg machine mass provides the stability needed for consistent precision grinding on heavy, large-diameter long workpieces

Limitations

4,800 x 2,600 mm footprint is the largest in the GA series, requiring significant dedicated floor space in the grinding department
8,500 kg machine weight requires verified floor load capacity and may need foundation reinforcement in some facilities
Price of $260,000-$350,000 is the highest in the GA series, reflecting the large-capacity construction
Single wheelhead limits multi-operation grinding; complex parts with both OD and angular features require multiple setups or additional equipment
Heavy workpiece loading may require overhead crane access, adding facility requirements beyond the machine itself

Best For

Power generation manufacturers grinding large turbine shafts, generator rotors, and bearing journals with multiple diameter steps across long lengths Marine equipment manufacturers grinding propeller shafts, rudder stocks, and large pump shafts requiring precision OD grinding over long lengths Heavy equipment manufacturers grinding large hydraulic cylinder rods, mine hoist drums, and crane components exceeding both 300 mm diameter and 500 mm length Aerospace manufacturers grinding large engine shafts and landing gear actuators with multiple precision bearing journals Steel and metals processing companies grinding large rolls and cylinders for rolling mills and converting equipment

Frequently Asked Questions

01 What does an Okuma GP-GA-47FII cost?

New pricing ranges from $260,000-$350,000 depending on options. This is the top of the GA series range. In-process gauging for multiple positions, heavy-duty steady rests, and specialized workpiece driving systems are common options that push toward the upper pricing range.

02 How does the GA-47FII compare to the GA-44FII?

Same 400 mm grinding diameter, but the GA-47FII doubles the center distance to 1,000 mm and provides 1,050 mm of Z-traverse vs 525 mm. Choose the GA-44FII for compact large-diameter parts and the GA-47FII when you need to grind long shafts with large diameters. The GA-47FII costs more and has a larger footprint.

03 What types of steady rests are available?

Okuma offers fixed and follow-rest configurations for the GA-47FII. Fixed rests support the workpiece at a set position, while follow rests travel with the grinding wheel during traverse grinding. For multi-journal shafts, multiple steady rest positions can be set up along the table. Self-centering hydraulic steady rests are available for production applications.

04 Can the GA-47FII handle very heavy workpieces?

Yes, with appropriate workpiece driving and support. The heavy-duty headstock, tailstock, and steady rest system accommodate heavy shaft-type workpieces. Overhead crane loading is typically required for the heaviest parts. Consult Okuma for maximum workpiece weight specifications based on your specific center height and support configuration.