This holder is half the size of the one I built some years ago. It consists of a flexure made from a truck’s leaf spring incorporating at one end a dovetail clamp and stem at the other. An internal screw jack pushes on a steel ball to flex the joint.
I made it because I needed a compact version and to see if I could still heat treat a spring
I made it because I needed a compact version and to see if I could still heat treat a spring