The device pictured below can be made from junk parts.
We used a trashed generator from an old Bell-47 helicopter attached to a 2X4.
Full View
Device was an armature from a helicopter generator.
All magnets and wires have been removed. The 3/8" shaft is mounted with two ball bearings, one on each end.
The bearings are held in place by strips of sheet metal wrapped over the bearings and tacked to the 2X4.
Close up View
Connecting unit with battery cables. Makes no difference which pole is connected to which bearing mount.
Armature spins in either direction when nudged into motion. Use a fresh 12 volt car battery.
CAUTION! Armature gets VERY HOT!!