I had made these sometime back not as complicated as the one noted here but have served me well and were easy to make. I made them originally for handling small parts but have come in handy for many other uses too. Recently made some more clamps specifically for 3/4" thick material stock holddown for my CNC machine table. The vise came in handy for using cnc machine as a drill press (which I presently do not have) for cutting a hole in the clamps at specific angle in which I was going to be using the clamp.
Two Different Size Clamps of same design
Note the small clamp with hole in the larger vise and also note the clamps intended use lower left corner of that vise (specifically designed for 3/4" stock which is what I use most of). The vise was ideal for this purpose because its base is 3/4" stock so the angle was perfect when placed into it for cutting/drilling hole.