Received the package right to my door, 250' down from the road.  Extra strong packing & all parts in perfect condition.  Step by step directions easy to follow.  The part #144 & similar one included with #516  has an exploded drawing showing twisting the part in place with a vertical arrow.  I assume that they were to be a tight fit but most of the receiver holes were a bit larger than the blue plastic ends.  To insure that the parts fit snug I filled the holes with an all purpose white glue and let them stand overnight with the parts in them.  Perfectly tight and sturdy assembly.  Be prepared to spend 2 or 3 hours +.  It's well worth the time to produce a very nice product... worth the money and time spent.