Which factors should be considered for the calculation of torque,and which should not?

(N/A) The role of moment of inertia and torque in the rotational motion of a rigid body is analogous to the role of mass and force in translational motion.
In the rotational motion of a rigid body,only the components of torque parallel to the fixed axis of rotation should be considered,as these components are responsible for the rotation of the body relative to that axis.
The components of torque perpendicular to the axis of rotation tend to rotate the axis itself from its position. To cancel the effect of these perpendicular components,an equal and opposite reaction torque is generated by the supports,keeping the axis steady. Therefore,the perpendicular components of torque are not considered in the calculation of rotational motion about a fixed axis.
In summary,for the calculation of torque about a fixed axis:
$(1)$ We consider only those forces that lie in planes perpendicular to the axis.
$(2)$ We consider only those components of the position vectors that are perpendicular to the axis.