EXACT step drill with straight groove, 4-20mm, HSS, TIN coating Application: For burr-free drilling and rubbing of sheets, pipes and profiles and single-sided deburring in one operation Drilling area: 4-20mm step height: 4mm total length: 67mm shank diameter: 8mm drilling stages: 2 mm rising 4-6-8-10-12-14-16-18-20 3-surface shank Stophers enable holes with different diameter levels in different materials up to 4.0 mm material thickness. The material thickness is determined by step height.