Apparatus for checking dimensions and/or shape of a mechanical part (2;61) comprising - a supporting frame (3;63), - one or more feelers (7,8;9;67,68) movable with respect to the supporting frame (3;63) and adapted to touch a surface of the mechanical part (2;61) to be checked, - an armset coupled to the supporting frame (3;63), carrying said one or more feelers (7,8;9;67,68) and including one or more thrust surfaces (15,16;17;74,75) in correspondence of said one or more feelers (7,8;9;67,68), - a transducer and/or display device (33;78) for detecting displacements of said one or more feelers (7,8;9;67,68), including a movable part (34;77), and - a mechanical transmission assembly coupled to said one or more feelers (7,8;9;67,68) and to said transducer and/or display device (33;78) and including o a shaft defining an axis, and o a guiding element adapted to cooperate with the shaft and to guide movements of the shaft along an axial direction, said movable part (34;77) of the transducer and/or display device (33;78) being adapted to move substantially along said axial direction, the apparatus being characterized in that said shaft of the mechanical transmission assembly includes - an abutment portion adapted to cooperate with said one or more feelers (7,8;9;67,68), said abutment portion defining an end abutment surface that is in contact with said one or more thrust surfaces (15, 16, 17, 74, 75) of the armset, - a guide portion that is at least partially housed in the guiding element and defines an end transversal surface in contact with said movable part (34;77) of the transducer and/or display device (33;78), and - a resiliently deformable portion between said abutment portion and guide portion. - a supporting frame (3;63), - one or more feelers (7,8;9;67,68) movable with respect to the supporting frame (3;63) and adapted to touch a surface of the mechanical part (2;61) to be checked, - an armset coupled to the supporting frame (3;63), carrying said one or more feelers (7,8;9;67,68) and including one or more thrust surfaces (15,16;17;74,75) in correspondence of said one or more feelers (7,8;9;67,68), - a transducer and/or display device (33;78) for detecting displacements of said one or more feelers (7,8;9;67,68), including a movable part (34;77), and - a mechanical transmission assembly coupled to said one or more feelers (7,8;9;67,68) and to said transducer and/or display device (33;78) and including o a shaft defining an axis, and o a guiding element adapted to cooperate with the shaft and to guide movements of the shaft along an axial direction, said movable part (34;77) of the transducer and/or display device (33;78) being adapted to move substantially along said axial direction, the apparatus being characterized in that said shaft of the mechanical transmission assembly includes o a shaft defining an axis, and o a guiding element adapted to cooperate with the shaft and to guide movements of the shaft along an axial direction, said movable part (34;77) of the transducer and/or display device (33;78) being adapted to move substantially along said axial direction, the apparatus being characterized in that said shaft of the mechanical transmission assembly includes - an abutment portion adapted to cooperate with said one or more feelers (7,8;9;67,68), said abutment portion defining an end abutment surface that is in contact with said one or more thrust surfaces (15, 16, 17, 74, 75) of the armset, - a guide portion that is at least partially housed in the guiding element and defines an end transversal surface in contact with said movable part (34;77) of the transducer and/or display device (33;78), and - a resiliently deformable portion between said abutment portion and guide portion.