Drill Blanks -- Number Sizes Excellent for use as gages, punches and special boring tools. Hardened and ground. High speed steel, jobber length. Tolerance sizes up to 1/4 inch (+0/-.0005 inch); 17/64 to 25/64 inch (+0/-.0009 inch); and 13/32 to 1/2 inch (+0/-.0010 inch).