Key benefits High precision cutting and drilling for consistent, repeatable results. Improves production efficiency on machine tools in the processing industry. Compatible set of tools (hex bolt-hole milling, countersink cutter, drill, straight-shank end mill) to handle common fastening and component-machining tasks. What each tool does and why you need it Hexagon bolt-hole milling cutter Function: precisely machines six-corner (hex) bolt holes. Benefit: creates accurate hexagonal bolt recesses for reliable fastener fit and torque transfer. Use with: machine tools in the processing industry for high-volume or precision production. Countersink cutter Function: provides centering and guidance for drilling and countersinking operations. Benefit: ensures accurate alignment of fasteners and clean countersink geometry, reducing rework and improving assembly quality. Drill Function: general drilling for holes and pre-drilling for countersinking. Materials: suitable for die steel, stainless steel, spring steel, general steel, cast parts, and aluminum parts. Benefit: versatile drilling performance across a wide range of metals and part types. Straight-shank milling cutter Function: general-purpose milling with a straight shank for secure toolholding. Benefit: stable cutting performance for finishing and profiling operations on machined parts. Performance and compatibility Designed for use on machine tools in the processing industry. Emphasizes high precision and high production efficiency to support consistent part quality and faster throughput. Covers common shop materials: die steel, stainless steel, spring steel, steel, castings, and aluminum. Typical use scenarios Assembly-ready bolt pockets: Mill precise hex bolt recesses in automotive brackets, machine housings, or structural components to ensure correct fastener seating and torque handling. Mold and die work: Drill and countersink features in tooling plates or die components made from die steel or cast materials, using the countersink cutter for accurate centering. General metal fabrication: Drill and mill holes and countersinks in aluminum parts, castings, and steel components for fabrication, repair, or prototype work. Additional note to buyers Due to lighting, monitor brightness, and manual measurement, there may be slight differences in color and size between the photos and the actual item. Please allow minor variations. Thank you for your understanding.