The CT-S Super Tite-Lock Milling Chucks incorporate dual-stage clamping for improved performance in both heavy milling and finish milling. For finish milling applications, tightening the chuck’s clamping ring until the black area on the toolholder body is no longer visible will achieve high gripping torque and minimum runout. For heavy milling applications, completely tightening the clamping ring will achieve maximum gripping torque. To improve performance over previous generation milling chucks, this tool incorporates a number of other advancements. Specially designed T-slots in the bore help to prevent slippage and pullout during heavy machining. Unique deep groove slots in the bore also increase gripping force and prevent cutting tool rotation.