# When does torque applied on a shaft produce bending and when does it not?

In both cases in the picture above torque is applied to the shaft, however in the first case the force $$F_{c}$$ also produces bending across the shaft. So my question is, how do I know if a torque should be shown with a force like in the first example, or with a torque vector like in the second example?

My best guess is that it depends on what produces the torque. Some ways do produce bending (like conic friction plates for example), while some don't.

In your first figure the force $$Fc$$ results in a moment along the vertical direction $$y$$ because the force is offset in the $$x$$ direction, as well as a moment along the $$z$$ direction because the force is offset in the $$y$$ direction.