A 13mm drill chuck key is a specialized tool used to tighten and loosen the jaws of a 13mm (1/2-inch) capacity drill chuck, securing the drill bit in place. These keys feature a specific gear tooth count and pilot diameter tailored to fit the chuck of your drill.Key Specifications & CompatibilityChuck Capacity: 1.5mm to 13mmMeasurement details: Typically features a 6mm pilot diameter, a ~17.5mm gear diameter, and 11 gear teeth (varies slightly by brand, such as Bosch, Makita, or Ingco).Connection Thread: Universal chucks usually mount with a 1/2"-20 UNF thread.