The Crescent Nicholson bastard cut mill files sharpen mill or circular saws and are ideal for draw filing and finishing metals. The rectangular shape lets you smooth and sharpen straight surfaces. 2 square edges allow you to make grooves fixed at the same width as the file, and all sizes taper slightly in width to improve access in slots. Bastard cut, American pattern mill file. Sharpens mill or circular saws. Great for draw filing and finishing metals. Rectangular shape lets you smooth and sharpen straight surfaces. All sizes taper slightly in width to improve access in slots. Great for draw filing and finishing metals.