Threaded self-aligning grippers have a hex-shaped body with a threaded stud that allows adjustment of their height to accurately position workpieces for machining and assembly processes. These grippers support and clamp workpieces or function as supports, stops, or thrust pads in jigs, fixtures and toolmaking applications. They have self-aligning inserts that accommodate uneven work surfaces, and built-in O-rings that secure the gripper's ball in place and prevent dirt and contaminants from entering the body. Inserts are replaceable and available in different materials and pad surfaces to meet specific application needs.