An apparatus and method for adding a velocity transducer to an electric motor, such as an elevator drive motor, includes mounting a shaft extension on an end surface of a motor shaft by drilling and tapping a bore at the shaft center as parallel as possible. A fastener with a bevel washer between a pair of flat washers attaches the extension to the motor shaft. With the fastener assembly snug, the extension is trued radially with a dial indicator. The bevel washer functions as a spring lock and distributes any off center clamping force produced from non-concentric hole drilling. A shoulder on the extension abuts the motor shaft end surface to maintain parallelism of the longitudinal axes of the shaft extension and the motor shaft. The shaft extension can be formed of an electrically nonconductive material to isolate the transducer from the drive equipment.