Martindale, OSSB072, Type SS Screw Slotting Saw 2-1/4" OD, 13 Frac 0.072" Dec Used for Cutting-off, slitting and slotting of Steel. Similar to slots in screw heads. Features: Ground Teeth M-2 High Speed Steel Hollow Ground For Side Clearance Rake Angle of Teeth: 0 Degree