What is a three-jaw chuck?

The three-jaw chuck consists of a chuck body, movable jaws and a jaw driving mechanism. Under the guide part of the three claws on the three-jaw chuck, there are threads that mesh with the flat threads on the back of the dish-shaped bevel gear. When the small bevel gear is turned with a wrench through the square hole, the dish-shaped gear rotates, and the flat threads on the back simultaneously drive the three claws toward or away from the center to clamp workpieces of different diameters. It is used to replace the three claws with three anti-claws to install workpieces with larger diameters. The self-centering accuracy of the three-jaw chuck is 0.05-0.15mm. The accuracy of processing workpieces with a three-jaw chuck is affected by the manufacturing accuracy of the chuck and the wear and tear after use.

The chuck is divided into two types: manual chuck and power chuck according to the power used to drive the jaws. ① Manual chuck: It is a universal accessory. The commonly used three-jaw chucks with automatic centering and four-jaw chucks with each jaw can move independently. The three-jaw chuck has a small bevel gear driving a large bevel gear. There is an Archimedean spiral groove on the back of the large bevel gear, which meshes with three claws. Therefore, by turning the small bevel gear with a wrench, the three claws can move in the radial direction at the same time to achieve automatic centering and clamping. It is suitable for clamping workpieces such as circles, regular triangles or regular hexagons.