Specialized category for jigs and chucks used to securely fix and position workpieces in machine tools. Includes lathe chucks (3-jaw, 4-jaw, collet), milling machine vises, machining center fixtures, grinding machine magnetic chucks, NC lathe hydraulic chucks, rotating centers, tailstocks, and index tables. Provides optimal gripping force and positional accuracy according to workpiece shape, material, and machining precision requirements, achieving vibration suppression and improved machining quality. Excludes simple tool holders and cutting tools, focusing specifically on workpiece fixturing machine device components.