Permsteading.com

One other thing that I failed to mention - the two 1' x 4' boards pass each pass through a dedicated cut out made into the superior horizontal board. It doesn't appear necessary to have two holes for one would likely suffice. At first glance, the portion of wood separating the two holes looks as if it provides the impetus for the "jaws" of the vise to open. In reality, it is the springiness of the two 1' x 4's that provides the force to spread the vise.

That said, if I attempt to make the above proposed change, the two 1' x 4's will pass through a common hole with a slightly smaller outside deminsion.

George, would the springiness be eliminated by replacing the horizontal with 8x2 like you used for the vertical, or is the springiness coming from the 'jaws'?
I had the same idea of using it for sharpening blades. I also plan to set up a forge in the future for making ulus, so the clamp would come in handy for sewing up the sheaths.

The springiness is in the jaws.

The two vertical boards are perfectly straight and are affixed to the base which, in this case is six inches wide. The boards want to be six inches apart along their entire length. The only time they aren't 6" apart is when they are being forced together. When the force causing them to come together is relieved, they spread.

This way does indeed work better.

Did you keep the same upright support or change it out for a beefier version, George"

The only thing different is the placement of the boards. By changing the position of the vise, and subsequently where one sits, we have changed the physics. Before, it was a Class 2 lever but now it is a Class 3 lever. As such, far less force is brought to bear on the resistance (vise) so with less force applied, those materials that previously felt too flimsy, now feel more than adequate.