To calculate the surface area of a cylinder: Work out the area of the two circular faces (2 × π\(r\)²). Work out the curved surface area, this is the rectangular face (2π\(r\) × \(h\)).

Milling and routing flat surfaces is pretty much the point of a CNC router, but how about curved surfaces? Auto leveling of hobby CNC machines and 3D printers is becoming commonplace, but Scorch ...