RedLine Tools - 4-40, 6-40 Carbide Thread Mill, AlCrN Coated UN Thread .0850 Cutting Diameter, 3 Flute - RM3006. $101.94 $ 101. 94. FREE delivery Feb 14 - 20 . Only 3 left in stock - order soon. RedLine Tools - 6-32, 8-32, 10-32 Carbide Thread Mill, AlCrN Coated UN Thread .1000 Cutting Diameter, 3 Flute - RM3011.