Machine Comparison
Okuma GI-20NII vs Okuma GP-47N
Okuma vs Okuma · CNC Grinding Machines
Summary
The Okuma GI-20NII and Okuma GP-47N are both from Okuma's cnc grinding machines lineup, making this a common upgrade or lineup decision for shops already invested in the Okuma ecosystem. The Okuma GP-47N leads in x travel (275 mm (10.83 in) vs 165 mm (6.50 in)). These machines are closely matched across most specifications, making the decision more about specific feature priorities, dealer support, and your existing shop ecosystem than raw spec advantages. Both machines are proven performers in production environments and represent solid investments for shops in the market for a cnc grinding machine.
Specifications Comparison
| Specification | Okuma GI-20NII | Okuma GP-47N |
|---|---|---|
| X-Axis Travel | 165 mm (6.50 in) | 275 mm (10.83 in) ▲ |
| Z-Axis Travel | 150 mm (5.91 in) | 525 mm (20.67 in) ▲ |
| Control | Okuma OSP-P300G | Okuma OSP-P300G |
| Min Feed Increment | 0.0001 mm (0.000004 in) | 0.0001 mm (0.000004 in) |
| Workhead Speed | 40 - 500 RPM ▲ | 10 - 400 RPM |
| Machine Weight | 5,000 kg (11,023 lb) | 7,000 kg (15,432 lb) ▲ |
| Floor Space | 3,200 x 2,400 mm (126 x 94 in) | 4,000 x 2,600 mm (157 x 102 in) ▲ |
| Price Range | $220,000 - $310,000 ▲ | $250,000 - $350,000 |
Advantages
Okuma GI-20NII
- Superior workhead speed at 40 - 500 RPM vs 10 - 400 RPM
- More competitive pricing at $220,000 - $310,000 compared to $250,000 - $350,000
- Backed by Okuma's dealer and service network for parts and support
- Bearing manufacturers grinding larger bearing race IDs, housing bores, and roller components in the 50-200 mm bore range
Okuma GP-47N
- Greater x travel of 275 mm (10.83 in) accommodates larger workpieces
- Greater z travel of 525 mm (20.67 in) accommodates larger workpieces
- Superior machine weight at 7,000 kg (15,432 lb) vs 5,000 kg (11,023 lb)
- Superior floor space at 4,000 x 2,600 mm (157 x 102 in) vs 3,200 x 2,400 mm (126 x 94 in)
Verdict
This is a close matchup. The Okuma GI-20NII and Okuma GP-47N trade advantages across different specifications, making neither a clear winner on paper alone. Your decision should come down to practical factors: which dealer is closer, which control system your operators already know, what tooling ecosystem you're invested in, and which machine's specific strengths match your highest-volume work. Get quotes on both, run test cuts with your actual parts if possible, and factor in long-term service and support costs.