... .ISO9001:2008 2.Professional manufacturer 3.Spiral flute 4.Good quality/Competitive price 5.Bright finished Step ... 2.) Spiral flute 3.) Step drill, bright finished 4.)HSS steel 5.) ISO9001Step drills are ground from solid ... 2.) Spiral flute 3.) Step drill, bright finished 4.)HSS steel 5.) ISO9001 Step drills are ground from ... Length(mm)Step QTY.4-12mm4,5,6,7,8,9,10,11,12mm65mm94-22mm4,6,8,10,12,14, ...