Shaft Locking Devices connect hubs solidly to shafts, using a keyless mechanical interference fit, to transmit torque or to withstand axial thrust. This mechanical interference fit utilizes screw tension in the Shaft Locking Device, converted into radial pressure via an inclined plane. This pressure expands the Shaft Locking Device to eliminate the gap between the hub and the shaft. The Shaft Locking Device uses the friction bond between the Shaft Locking Device and the shaft/hub to create a zero backlash connection. This connection is easily releasable to remove the mechanical interference fit.