Fork of the self-centering oscillating type, particularly for the bending angle measuring, in a pressbrake including at least a fork provided along a matrix or a matrix fractioned element, able to detect the real inclination of the two specular planes of a pressed-bent sheet-plate, each having two detection points, one of which is static and known, and the other one is dynamic. The fork including a forked end and a relative shank which interacts with a position transducer, communicating with a data processing logic unit which controls the pressbrake. The fork being hinged in correspondence with the shank top.