There were two manufacturing defects.  The first one is that one of the buttons to lock one of the rods in place was misplaced so that it wouldn't line up with the hole.  It still went together and I don't think it will come apart at that juncture.  I could not get the top on even using WD40.  My son came over and manhandled it and got it to fit.   This is the second one they sent me.  The first one arrived in a box that was coming open and looking like it had been through a tornado and parts were missing.