A step is cut into a stationary or movable flange in a two-flange engagement. As the two flanges are brought closer to one another by tightening a nut or knob attached to a central shaft, contact is established along the edge of the step. Contact along this line does not create a point contact about which the flanges will pivot. Therefore, consistent friction is obtained when tension is applied by tightening the nut and the flanges are brought into contact.