HHIP 13/16 x 1 Inch Depth M35 Cobalt annular cutter is best used for making heavy cuts, at high speeds and feeds, or where high heat is a factor. Pilot hole. 3/4" diameter shank. Produces a slug of material. High heat and abrasion resistant properties. M35 Cobalt (5%) is designed to cut difficult and abrasive materials ranging from medium to high hardness, such as castings and forgings.