Apparatus and methods for a magnetic coupling motor drive for a surgical cutting instrument. A magnetic coupling motor drive unit includes a motor housing containing a motor and a magnetic drive hub assembly, the magnetic drive hub assembly having a drive hub and a driven hub, the driven hub rotating about a driven hub spindle, the driven hub spindle attached to a seal cap, the seal cap sealing the drive hub and the motor to the motor housing, wherein the drive hub includes an array of magnets aligned to a respective array of magnets in the driven hub.