A double rotatable spindle head of non-perpendicular axis type has a first half
head and a second half head. The first half head is connected to the machine structure
and rotates about a first axis. The second half head is coupled to the first half
head on a flat surface and rotates about a second axis perpendicular to the flat
surface. The rotation of the first and second half heads is achieved by a first
and second direct motor, respectively.