... bits 2.) Spiral flute 3.) Step drill, bright finished 4.)HSS steel 5.) ISO9001Step drills are ground from solid high ... bits 2.) Spiral flute 3.) Step drill, bright finished 4.)HSS steel 5.) ISO9001 Step drills are ground from solid ... rejection. SizeDiameter ListOverall Length(mm)Step QTY.4-12mm4,5,6,7,8,9,10,11,12mm65mm94-22mm4,6,8,10 ... ,18,20,22,24,26,28,30,32mm105mm156-38mm6,9,13,16,19,21,23,26,29,32,35, ...