These are a little tricky to assemble as the two tall shafts come in 3 internally threaded pieces, held together after assembly by loose threaded connector pieces designed to thread half way into one shaft piece and half way into the next one inside the shafts.  The issue is that since the connector piece is free moving, its difficult to ensure it stays threaded equally (or close to equally into both sides.  We bought 10 of these to light a large room around the edges, so I got good at assembling them after the first 2-3.  They've worked great and we love the look of them them.