The invention is a gauge and method for measuring any circular object, but is most useful as a precision thread gauge for objects having either external or internal threads. A fixed gauge roll is supported in a stationary position. A first and second gauge rolls are supported so that the first and second gauge rolls simultaneously move with respect to the fixed gauge roll. The fixed gauge roll, first and second gauge roll together form a triangle. The interior angles of the triangle remain unchanged for every position of the three gauge rolls.