A HSS centre drill is a type of drill bit used for drilling the center of a hole. It is typically used to drill a hole in the center of a piece of material, such as a piece of metal or wood. The drill bit is designed to create a conical shape that is used to locate and hold a center punch in place while drilling. This is done to ensure that the hole is properly centered. Common uses for HSS centre drills include drilling out pilot holes for larger drill bits and drilling out dowel holes in woodworking projects.