I use a shop-built table with T-tracks set into the top for most of my assembly work. But even with a dedicated assembly table, my pipe clamps are oftentimes too long to sit on the table. To help support my clamps, I made several of these pipe clamp stands that lock in place in the T-track.
Start by gluing a couple pieces of MDF together. The pieces should be large enough so that when trimmed to size they yield two stands. I then drilled a hole slightly larger than the diameter of the pipe clamps and cut the piece in half through the center of the hole. All that’s left is to chamfer the edges and glue it to the base.