A measuring tool (1) for measuring dimensional characteristics (D) of a production part (2). The tool (1) comprises a unit (3a, 3b) for positioning the measuring tool (1) relative to the part (2) and at least one measuring apparatus (4a, 4b) mechanically linked to the positioning unit (3a, 3b) by a mechanical link (5). The positioning unit (3a, 3b) comprises a first centring device (6a) for coming into contact against an inner surface (7a) of a first bore (22a1) of the production part (2) and a second centring device (6b) for coming into contact against an inner surface (7b) of a second bore (22b1) of the production part (2), the first and second bores (22a1, 22b1) being coaxial. The mechanical link (5) allows the relative displacement of the measuring apparatus (4a, 4b) relative to the first and second centring devices (6a, 6b).