Creating a concentric bowl is a challenge. One I have to play with to master. You can see from the bottom picture the when I was trying to remove the inner circle, a crack formed to the outer edge. I've got some ideas on how to work around this.
First, I could sacrifice the glass at the center and possibly make a number of cuts through the middle, hoping to get enough play to release it. Second, I could drill a small hole in the center before making my cut and try to score to that.
Third, I could cut 2 distinct half circles for the outer edge, thereby having a consistent cut, but the lines will still be visible in the final piece. I believe that the project will look even better when there is not a visible line in the edge piece, so I will aim for that in future pieces.
The other challenge to the plate was the inner circle. I cut it the same diameter as the inner piece. This require a bit more grinding than I would have liked to done and left some small gaps. They can't be seen now, but in the future, I will slightly shrink the inner circle next time.
