Is it possible to set a rotating axle?

Hello guys,
In this brand new project I wanted to make pop-out headlights in my F40 model, by simply rotating them in object mode (ref image: https://i.imgur.com/m6p1WNi.jpg).

The problem is: how am I supposed to lock a rotation angle that is not X, Y or Z. Can I somehow take an edge of the mesh and define the rotation angle? Thanks.


It is far simpler: press R to rotate and then press the corresponding axis key two times (in your case x). This will change the rotation axis from global to local.