If you don’t own a traditional steel hold-down, here’s a way to secure objects to your bench when you can’t reach them with ordinary clamps. Find a pice of scrap-wood that is slightly thicker than the workpiece and place it on your bench parallel with the edge. Next, lay another piece of scrap-wood on top of and perpendicular to the thick piece and the work piece. Position a C-Clamp so that the jaws extend beyond the thick piece. When you tighten the clamp, this makeshift hold-down will exert considerable pressure on the workpiece.
-John Plank Sr.