I must be dumb as a rock. I have these and rarely use them. I tried again today and realized why I never use them. The side with the screw drive is square to the pipe. The side that slides on the pipe is not. When I use them, it raises up the board closest to the side opposite the screw. It must be something simple that I have not done correctly. I have used them before by putting a wedge in between the board and the off square side but hate to do this as I have other clamps. I have only used these when I need a very long clamp. Any idea what I am doing wrong?