This past weekend I made a server rack for my shed out of 2x4s. I used the design concept from Mythos & Rini which I tweaked slightly for my space. I needed a short rack I could wheel out from under a shelf. This rack is screwed together and feels very sturdy. The front wheels as locking casters so I can keep it in place in my shed.
While making this rack I learned that the industry standard for rack widths is 17.75 inches wide and that 1U is 1.75 inches.