By cutting experiments, this paper investigates the effect of various chamfer widths and chamfer angles on cutting force, cutting temperature, and chip morphology when hardened steel GCr15(HRC60+2) is machined with PCBN tools. The research results indicate that with the enlargement of chamfer angle both cutting temperature and main cutting force increase gradually, and especially, radial force increases more significantly. In addition, it is shown that as chamfer width increases both cutting force and cutting temperature rise. The analytical results of chips derived from cutting experiments reveal that chamfer angle being 20º, chips are the thickest and less serrated. Furthermore, chip thickness diminishes gradually with the increment of chamfer width.