Martindale, OSSB051, Type SS Screw Slotting Saw 2-1/4" OD, 16 Frac 0.051" 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