The finished C-clamp rack...

The finished C-clamp rack...  Per a reader's request, here it is (at right).  The photo is a bit of an optical illusion: the rack is actually perfectly level, though it looks like the right side is slanted sharply downward.  What's really going on is that it's mounted on the wall encasing a set of stairs (to my loft and office), and the bottom of that wall is slanted sharply up!