This an axle for a homemade DC motor. The ends fit into a 8mm ball bearing which can then be mounter to a stationary object. The holes are to wrap coils of wire into to create the electromagnetic field that runs the motor.

MakerBot

MakerBot Replicator+

Doesn't Matter

Yes

When printing make sure the model is facing upright so that it is as tall as possible and make sure to put supports or else the print will not work.