... Step drill with spiral flute1.) Step drill bits 2.) Spiral flute 3.) Step drill, bright finished 4.)HSS steel 5.) ISO9001Step ... are ground from solid high speed steel. A range of hole diameters can be drilled using only one tool and holes ... ,19,21,23,26,29,32,35,38mm100mm126-40mm6,11,17,23,29,30,31,32,33,34,35,36,37 ... 38,39,40mm105mm1610-20mm10,11,12,13,14,15,16,17,18,19,20mm88mm11 Step drill with spiral ...