General description The AlwaysH 4pcs Countersink Deburring Chamfer Conical Drill Bit set is designed for precise cutting in various materials including metal, wood, plastic, and thin iron plates with a hardness of less than 25 degrees. The drill bits feature a 90-degree tip for clean and accurate milling, making them ideal for chamfering round holes or tapered holes in workpieces. Technical specifications Material: High speed steel Sizes: 2-5mm (hole size), handle 6mm, head diameter 9.7mm Sizes: 5-10mm (hole size), handle 8mm, head diameter 14mm Sizes: 10-15mm (hole size), handle 10mm, head diameter 21mm Sizes: 15-20mm (hole size), handle 12mm, head diameter 28mm Installation Recommended use with a bench drill to minimize shaking. Using a hand drill may affect the chamfering effect. Other information All measurements are taken manually; allow for a 1-3cm error due to lighting and display differences. Please refer to the actual item received for precise details.