Here is a table for the grades of steel used in the motor shafts of Parker Servo Motors.
| Motor series | Shaft alloy grade |
| N, J | 1144 carbon steel |
| SM, BE | 303 stainless steel |
| SMN, M | 39NiCrMo3 |
| MPM | 416 stainless steel |
| MPP | 416 stainless steel |
| MPW | 316 stainless steel |