You know when you want to extract a short, unbroken stud from a casting without damaging it, but it's stuck tight? Well I never found a good way. But I had an idea this afternoon. I took a hex nut, cut a radial slit through the nut, screwed it onto the stud, and squeezed it tight in a mole wrench. So it worked a bit like a collet. It turned the stud out easily. Here's a picture:
Chris