I need to drill two concentric holes on a 10 mm. polycarbonate sheet. The first one is 50 mm (diameter) and 6 mm. deep, while the second is 30 mm. (diameter) and goes through the sheet. I am not familiar with the polycarbonate material and I am not sure if what I am describing is even possible. In case it is possible, which tools can I use, I thought in using a 50 mm hole saw, but the afterwards I am not sure how to carve the remaining material. The idea is depicted in the schema.
Use a 30 mm hole saw for the hole going through, on the bottom side use a router with a rabbet cutter with a dimension of 10 mm from the bearing top the cutter edge.
When using the router on the bottom side, tape the surface where the router will be to eliminate the possibility of scratching the plastic.
Using a drill press to keep the hole saw square would help keep the router from making a slightly oval cut.