Item Type: Milling Cutter HolderMaterial: 40CRModel: R8 ER25(7/16-20)R8 threaded shaftDrawbar: 7/16Use: R8 dedicated machineTotal Tightening Accuracy: 0.00Rounding: 0.8mmSurface Roughness: >0.8mmStandard Speed: Below 10000rpmSurface Roughness: >0.8mmStandard Speed: Below 10000rpmPackage List1 x Milling Cutter Holder1 x Storage Box1Accurate Workmanship: This milling cutter holder has a high accuracy performance and can be tightly fixed on the drill bit, which can ensure the safety and stability of the user. 2Polishing and Hardening Treatment: The chuck holder is accurately polished and hardened to increase stability, avoid carbide shaft breakage, and increase tool feed rate and cutting volume. 3High Efficiency: This milling cutter holder uses fewer extension tools, resulting in increased efficiency, which provides a better work experience. 4Wide Application: CNC milling tool holder straight extension handle is suitable for deep machining and solves the need of deep machining. It is suitable for lathe, drilling machine and milling machine, which brings great convenience to people's work. 5Tempered Forging: Milling cutter holder is made of 40CR material, repeatedly tempered and forged, it has a very high hardness and stable structure.