Carbide is the edge of choice for turners because it stays sharp maintaining its cutting edge up to 20 longer than HSS! This carbide insert fits many of the woodturning tools on the market today. Recommended for tools with a 3/8″ shank for the best support. Insert is supplied with an alloy #4-40 x 5/16″ flat cap screw. The mounting hole in the insert is 5/32″ with a standard countersink. Orders of 3 or more come with a replacement 1/16″ allen wrench. Fits: Easy Wood Tools (Any tool using Ci2-SQ or Ci2-R2 insert cutter), Easy Start Rougher, Mini Easy Rougher, Mid-Size Easy Rougher, Pennstate Industries Carbide Magic Pen Genie and Ultra Carbide Chisel system, Craft Supplies Easy Pen Tool, many others!