HHIP USA Made 4.0 X 10mm Carbide Center Drill and Countersink Size 4.0 plain style with a 10mm body diameter. Ground high speed steel 60 degree center drill and countersinks are essential tools for achieving accurate hole preparation and machining operations in metalworking and manufacturing environments. Their combination design, precision cutting capabilities, durability, and versatility make them indispensable for professionals seeking high-quality results. Used for centering work ends, where the workpiece is to be revolved on machine centers, the 60 degree countersink angle fits all standard centers. A combined center drill is a tool that can both drill and countersink a hole in one operation. It can be used to create a tapered feature in the end of a part or stock to provide a secure contact point for a live or dead center. The straight pilot drill section starts the hole and provides clearance for the point of the center, so it does not contact the bottom of the hole. Ideal for chamfering or spot drilling.