Abstract: A blade, such as the blade of a precision shear, having a cutting angle which changes progressively along the length of the blade through a predetermined angular measure is sharpened by coupling the blade with an articulated arm assembly through a drive mechanism which rotates the blade about a longitudinal direction in response to movement of the blade along the longitudinal direction, as the blade is drawn across a sharpening surface. The drive mechanism includes a cam and follower for rotating the blade through an angular displacement corresponding to the predetermined angular measure of the change in the cutting angle so as to preserve the changing cutting angle. The drive mechanism is selectively uncoupled to permit free manual rotation of the blade as the blade is drawn across the sharpening surface for finishing the blade subsequent to the sharpening operation. The drive mechanism accommodates blades of both right-handed shears and left-handed shears.