A flat reamer (200) has a reamer shaft (270) and two opposite blade wings (220, 221). The blade wings have a proximal reamer area (202) with first cutting areas (240-241) and second cutting areas (250-252) intermittently separated by first recesses (245-246) and second recesses (255-256), respectively. The cutting areas have variable sharpness with the highest sharpness at the center and decreasing to the outside.
