Thread these chucks onto the spindle of portable drills and stationary machines to hold bits. They're a keyed chuck, so they hold the bit tightly, preventing it from slipping under load. Use the included key to tighten and loosen the jaws. If your machine doesn’t have a threaded spindle, mount them with a threaded drill chuck arbor.

To maximize grip and minimize wobble, choose a chuck where your drill bit diameter falls in the middle of the shank size range.

Heavy duty chucks give you the rigidity and heft needed for high-torque drilling in hardened metal. Their extra mass means they resist vibration and fluctuating cutting forces to keep your bit stable. While they share all of the same features as medium duty chucks—one-piece sleeve, center-ground jaws, and hardened wear points—they grip bits tighter and stay accurate longer under heavy loads.