Suitable size: shafts have diameters of 7 mm (0.28 inch), 8 mm (0.32 inch), 9.5 mm (3/8 inch), and 10 mm (0.39 inch); the cutting head measures approximately 19 mm (3/4 inch) in external diameter and 6 mm (0.24 inch) in inner diameter; the "O" style sleeve adapter fits pilot shafts over 7 mm to maintain center alignment Quality material: cutter shafts are made of solid carbon steel, offering rust resistance, strength, and durability with excellent cutting performance for efficient drilling; the sleeve adapter is constructed from brass; this pen barrel trimmer kit provides a practical and convenient solution for pen blank preparation Easy to clean: cutting shafts allow for easy removal of excess glue, wood debris, and impurities from tubes, resulting in smoother and flatter tube cuts; ensure proper mounting of the cutting shafts into a drill or lathe chuck before use Various applications: shafts are compatible with drill chucks, lathe chucks, drill presses, and hand drills; useful for pen polishing, hole milling, and cleaning inner tubes due to their compact size Increased efficiency: multiple shaft sizes meet various needs in woodworking projects, helping improve work efficiency and reduce effort during drilling and milling operations Durable cutting head: the pen barrel trimming set features a solid and durable cutting head with a pointed edge for precise cutting; maintains sharpness through repeated use and supports easy polishing for surface flatness Color: Silver Material: Metal Package Contents: 4 x pilot cutter shafts in different sizes 1 x cutting head 1 x sleeve adapter 1 x hex key wrench Note: Contains small parts; not intended for children Only the items listed are included; additional products not included Note: Lighting and display differences may cause slight variations in color between the image and actual item; measurement tolerance is +/- 1-3 cm