Harvey Tool 896444-C6 | 1/4-20 Thread 0.1870" Diameter 1/2"FL Coated 0.5000" Helical Flute Thread MillFeatures Designed for threading in hardened steels and difficult to machine materials Left hand cut, left hand spiral designed for climb milling from top to bottom of right hand threads Three forms and helical design reduces tool pressure and deflection resulting in accurate threads Cuts internal 60 Degree UN threads Able to cut larger threads of the same pitch h6 shank tolerance for high precision tool holders Latest generation AlTiN Nano coating