American Carbide Tool Carbide-Tipped Tool Bit for Threading, Neutral, C6 Grade, 0.25" Square Shank, E 4 Size E-style tool shape has a sharp tip with a 60-degree angle for fine threading C6 grade uncoated carbide tip for machining of steel and steel alloys Neutral cutting direction for right-to-left or left-to-right feed Positive rake angle provides a sharp edge for making continuous cuts Square steel shank fits square toolholders