Machine Comparison
Okuma GI-20NII vs Okuma GP-47N
Okuma vs Okuma · CNC Grinding Machines
Summary
The Okuma GI-20NII and the Okuma GP-47N are Okuma CNC grinders for different surfaces. The Okuma GI-20NII is an internal grinder for bores, including long bores with its center rest option and small bores with high-frequency spindles. The Okuma GP-47N is a cylindrical grinder for long, heavy shafts held between centers.
Okuma publishes few comparable figures for this pair. The one row the table holds is rapid traverse, and it is a tie at 12 m/min (472 ipm). With no figure separating them, the choice comes down to the work: inside diameters on the Okuma GI-20NII, outside diameters of shafts, journals and seats on the Okuma GP-47N.
Specifications Comparison
| Specification | Okuma GI-20NII | Okuma GP-47N |
|---|---|---|
| Rapid Traverse | 12 m/min (472 ipm) | 12 m/min (472 ipm) |
Advantages
Okuma GI-20NII
- Grinds inside diameters, which a between-centers shaft grinder is not built for
- Center rest option for long bores and high-frequency spindles for small bores
Okuma GP-47N
- Grinds outside diameters on long shafts held between centers
- Suited to plunge grinding of journals and seats
- Low workhead speeds for heavy shafts
Verdict
These grinders do different jobs, so choose by the feature on the part. Shops grinding bores, whether short production bores or long ones that need a center rest, should choose the Okuma GI-20NII. Shops grinding journals and seats on long, heavy shafts should choose the Okuma GP-47N. The shared 12 m/min (472 ipm) rapid traverse gives no reason to prefer either, and neither machine can take over the other's work.