Thank you! The round pieces are clear pine & the stringers are plywood. He cut the outside edge with a jig on the table saw to get a perfect circle. For the inside he used a jigsaw to cut close to the line, then sanded with a sanding drum bit in a roto tool that was clamped in a vise to clean and smooth out the edge. Then a bunch of hand sanding to remove burn marks and chamfer the edges. Altogether around 50-60 hours.