To rotate an axial load LEGO developed the turn table. For light loads this works great but the friction increases dramatically with heavy loads. This thrust ball bearing uses standard LEGO balls to transform the friction into rotations. This allows the two disks to easily rotate. The balls and an additional rim keep the two disks in place.
A motor can be attached on the inside to power the rotation. Even the smallest LEGO motor is sufficient to easily rotate this 2 kg load. This thrust ball bearing is fully LEGO compatible and even allows studs to be attached to top half. Standard 14.2 mm LEGO balls can be used. The bearing measures 20 studs across and is three bricks high. This should be big enough for even the biggest crane or MOC display.
The 3D data is available from the Autodesk Gallery.