US Patent 10476350 Electric motor for a power tool

An electric motor includes first and second balancing members coupled to an output shaft for rotation with a rotor. The first and second balancing members substantially balance a mass of the rotor about a longitudinal axis of the output shaft to reduce vibrations of the electric motor during use. The first balancing member includes a brass bushing supported on the output shaft adjacent a first face of the body of the rotor. The brass bushing includes a hole drilled into an outer circumference of the brass bushing providing a first balancing feature of the electric motor. The second balancing member includes a fan supported on the output shaft adjacent a second face of the body of the rotor. The fan includes a plurality of fins extending from a first face of the fan and a second balancing feature of material removed from a second face of the fan.