Simple Fidget Spinner

Guess I am somewhat stuck on this project. Here is a copy of my project file.

FidgetSpinner.3dm (3.1 MB)

The object still appears to be extrusions and polysurfaces in Rhino. You can see the full circles outlines I extruded and the wedge piece of the square. I am wondering how to join all the parts into one solid object.

When I choose to fillet the edges, select gives me the inner part of the circle and overlap. I just want the outer edges, outer part of each circle.

When I export to STL and slice with Simplify3D, the model initially looks great, but once sliced, the preview shows three triangles open around the center hole, and the slicer is basically recreating circles around each open hole, rather than treating it like a solid object. There is also a wedge gap on the outer border of the body and the circle.

What I was hoping for is this object to print.

If anyone has any ideas to assist me, I would very much appreciate it.

Thanks,

Jerold