DOOR HARDWARE - Fitting Door Knobs And Back Plates Together

Question: How do I know what door knobs will work with a particular rosette or door plate?
Answer: This is determined by measuring the inside diameter of the collar on the door plate or rosette and then measuring the outside diameter of the base or shank of the door knob or lever. The knob shank diameter should be a little less than the inside collar diameter on the rosette.