The locking screws are also a very simple concept. I simply bored holes into one of the outside leg components, just above the bottom brass guides, and screwed in a 3/8" brass threaded insert. The insert has course threads on the outside to screw into the wood and 3/8" machine threads on the inside. I bought the knobs with a 3/8" threaded bolt from my local hardware store for around $3 each. This was more than I wanted to spend on that component but it was a perfect solution. So what the heck, I bought them!

(ABOVE:) The Lower (Fixed) Brass Guides Are Fastened To The Outside Leg Components. You Can See The Locking Knob And  The Eye For The Spreader Chain

The threaded bolt of the locking knob simply screws through the insert on the outside leg component, to press against the center component. Since the legs are red oak, a hard-dense wood, the adjustable screw doesn't dig into the wood but it leaves dimples from the threaded bolt. If this becomes a problem, I may later add a thin strip of stainless steel sheet on that side of the center leg component.

I also added a spreader made of brass chain as a saftey device. I screwed in eyes to the lower end of one of the outside components of each leg. The three 12" brass chains meet in the middle and attach to a ring at the center. Next>>>