The pics were originally to large, I had to resize them to get them to upload.

Note that there is a 2x6 a hair more than 1 1/2" above the bench surface. This allows a 2x4; 2x6; etc. to "wedge" between the top of the bench and the 2x6 that runs parallel to the top. A press, vise, or whatever you want to be mounted can be locked into the bench. In the case of my Dillon, it is mounted on a double layer of 3/4" plywood to make the 1 1/2" thickness to fit tight. This system also requires a clamp to be used on the leading edge of the press or device you are trying to secure.

I despise a wobbly weak workbench! The top is two layers of 3/4" plywood plus another 3/4" layer of hardwood flooring. The braces are considered "architectural" grade and very heavy, utilized at every stud. Note that addition support is added with another 2x6 under the back edge of the surface, and there are 2x4s layed flat under the brace legs.

This set up is rock solid, even when I have my vice locked it and banging on the flat anvil section of the vice with a 3lb hammer.