Spiral step drill bit designed for fast, accurate drilling and chamfering in a single tool. The twostage step profile performs reaming and countersinking in one pass, reducing tool changes and saving time when preparing holes for fasteners or fittings. Key benefits Two functions in one tool: reaming and chamfering combined to streamline hole preparation and improve processing efficiency. Two available step angles: 90 and 180 for countersink geometry choices to match screw or nut seating requirements. HSS countersunk head for cutting a wide range of materials up to 30 HRC, including cast iron, tool steel, copper, aluminum, alloy steel, iron, and die steel. Spiral flute design promotes efficient chip evacuation and cleaner hole finish. Replaces multiple drill operations when creating stepped holes for installing fasteners such as hex nuts or countersunk screws. Product features Product name: Spiral step drill bit Material: HSS speed steel Color: Black Optional step angles: 90, 180 Available sizes: M3, M4, M5, M6, M8, M10, M12 Suitable for: Drilling and chamfering Quantity: 1 Pc per package Typical applications Create stepped holes and countersinks for flushmounted screws and bolts in metal fabrication and assembly. Drill and chamfer holes for installing hex nuts or fasteners in machinery, brackets, and enclosures. Deburr and chamfer drilled holes in sheet metal and plate work to improve fit and finish. What makes it practical Combines two machining operations in one pass to reduce setup time and tool changes. HSS construction balances hardness and toughness for reliable performance on metals and some nonmetal materials below 30 HRC. Multiple size and angle options let you match the tool to common fastener sizes and seating geometries. Package contents 1 x Spiral step drill bit Important notes Total length may vary slightly between production batches; this does not affect use or performance. Actual item color may differ slightly from images due to monitor and lighting differences. Please allow slight manual measurement deviations for listed dimensions.