. The addition of a keyway allows for use in positive drive applications as a shaft collar or for extra torque capacity when used as a rigid coupling.Tightly controlled face to bore perpendicularity is maintained (TIR of This two-piece double wide shaft collar has a 1.0000", Steel, OD 1 3/4" Ruland clamp style shaft collars do not mar the shaft, are infinitely adjustable, and have superior holding power when compared to set screw collars.