Method for measuring or checking dimensions of a mechanical part which comprises a first surface and a hole, the hole defining a second surface, a connecting surface between said first and second surfaces and a substantially circular edge, by means of a checking apparatus comprising • a supporting frame movable with respect to the mechanical part at least along a first direction, • a first feeler movably connected to the supporting frame at least along the first direction, • a second feeler movably connected to the supporting frame at least along a second direction perpendicular to said first direction, • the first and the second feelers being spaced apart from each other along said first direction by a fixed space, • a first transducer coupled to the first feeler and adapted to provide signals responsive to displacements of the first feeler with respect to the supporting frame along said first direction, and • a second transducer coupled to the second feeler and adapted to provide signals responsive to displacements of the second feeler with respect to the supporting frame along said second direction, the method comprising the following steps: (i) arranging the supporting frame in a starting position, (ii) causing a mutual movement between the supporting frame and the mechanical part along the first direction, during said mutual movement: a. the second feeler performs an at least partial scan of the connecting surface and the second transducer provides a relative scanning signal, and b. the first feeler cooperates with the first surface and the first transducer provides a relative reference signal, said scanning signal and reference signal being mutually synchronized, and (iii) performing a calculation of the distance of said edge from the first surface along the first direction based on said synchronized reference and scanning signals and on said fixed space. • a supporting frame movable with respect to the mechanical part at least along a first direction, • a first feeler movably connected to the supporting frame at least along the first direction, • a second feeler movably connected to the supporting frame at least along a second direction perpendicular to said first direction, • the first and the second feelers being spaced apart from each other along said first direction by a fixed space, • a first transducer coupled to the first feeler and adapted to provide signals responsive to displacements of the first feeler with respect to the supporting frame along said first direction, and • a second transducer coupled to the second feeler and adapted to provide signals responsive to displacements of the second feeler with respect to the supporting frame along said second direction, (i) arranging the supporting frame in a starting position, (ii) causing a mutual movement between the supporting frame and the mechanical part along the first direction, during said mutual movement: a. the second feeler performs an at least partial scan of the connecting surface and the second transducer provides a relative scanning signal, and b. the first feeler cooperates with the first surface and the first transducer provides a relative reference signal, said scanning signal and reference signal being mutually synchronized, and a. the second feeler performs an at least partial scan of the connecting surface and the second transducer provides a relative scanning signal, and b. the first feeler cooperates with the first surface and the first transducer provides a relative reference signal, said scanning signal and reference signal being mutually synchronized, and (iii) performing a calculation of the distance of said edge from the first surface along the first direction based on said synchronized reference and scanning signals and on said fixed space.