Item Type: Shell Mill Arbor Adapter Material: 40CrMnTi Model: R8 FMB40 Accuracy: 0.005mm Hardness: >HRC50-553 Thread size: 7/16-20 Package List 1 x Shell Mill Arbor Adapter 140CrMnTi Material: The milling cutter shank has high thermal strength and oxidation resistance, as well as good comprehensive mechanical properties, fully carburized heat treatment for inner and outer diameter grinding, strong wear resistance and stable quality. 2Quenching Process: The quenching process on the surface of the milling cutter shank increases the hardness of the object, and it will not deform after long term use. 3Not Easy to Swing: The milling cutter handle has a double sided card key and double sided restraint. It is not easy to swing left and right during heavy cutting to ensure processing rigidity. 4High Accuracy: The accuracy of this milling cutter head is as high as 0.005mm, which can perfectly complete the tasks you need to complete. 5Main Application: The tool used by the CNC milling machine can be connected to the spindle through the tool holder, and the speed and torsion are transmitted by the tool holder, and the milling cutter is rotated to achieve the purpose of milling the workpiece.