It's handy to have a small rack to hold PCB's while you're building them. This little rack is printable in sections of 4. The racks snap together with dovetails, and have screw holes for mounting to a large board.After printing you may have to adjust the dovetails a bit. Use a triangular jeweler's file. Since the dovetails are 60 degrees, the triangular file works perfect. You can fasten these down to a larger board using #4 screws (or 3mm. Double sided tabe or carpet tape also works well.