I've been watching you tube videos lately, and seen welding school shops and in their booths they had posts with a small steel table and then adjustable arms to move to where you like. I know the generally jist of them. I would like to fab one up for myself to work on vertical welding and to try overhead. But I don't know how to make the clamping mechanism to hold the steel. And to be able to hold metal for butt welds fillets and others, I have not seen one up close, so I would like to know how they clamp the metal so i can make one of my own, any help or pictures would be great! Thanks for your time!