Three-jaw chuck Zinc alloy body material, inner diameter and outer diameter dual-purpose collet, used for DIY workbench, mini milling table, drill, etc. Easy to tighten & nbsp; Insert the pin clockwise or counterclockwise to fix and loosen, change the tightening mode (external tightening, internal tightening). Clamping range & nbsp; Outer Diameter: 12mm-65mm (solid processing cylindrical materials, wood, steel, copper, aluminum and other round bar); inner diameter: 1.8mm-56mm (processing materials of inner hole); exterior surface treatment. The base mounting hole & nbsp; It is convenient for you to fix it on your workbench, milling machine, woodworking workbench. Simple and fast. Note The jaws do not have serrations, which is convenient for DIY. Usually, it will not fall off during processing, but too fast speed is not suitable for the secondary chuck. You can grind the jaws to avoid sliding.