After having an ideao for  the design, we began by working on modeling.
We started modeling with the chessboard. It set the dimensions for the rail, gripper, and pieces. 

The sphere is 20 cm in diameter.

For inspiration, as mentioned in our first log, we looked at Orb Chess by NKD Puzzle :

We first began modeling the spherical chessboard :

Since we are 3D printing it, we designed the board in 4 identical sections that connect with M3 screws or glue. We also made a custom coupling to mount the sphere onto a threaded rod. 

The squares fit into the sphere like puzzle pieces. Each square has a hole for a magnet so the chess pieces stay attached to the board.

Here is the fully assembled spherical chessboard.