I had an old timer to show me this trick several years ago. It's an easy and quick way to get the center point on a square blank for centering in a lathe. Just rip a piece of scrap 1/16" narrower than half the width of your square blank. Lay it down on the bench against the blank and make a mark across the end of the square. Do this 4 times,turning your square, and you have a center point. Ths eliminates dragging out the tri-square and holding it up on end fumbling around trying to mark it. Steve