I received this lamp months ago and have never had the opportunity to address the following issue.  I am using it as lighting over my work desk.  I is a very heavy lamp and the base is large.  After moving all of my computer equipment and desk, I was able to situate in the corner behind my L-shaped desk.  It had to be put in place BEFORE I put the lamp shades on it.  I began to put the 5 lamp shades on only to discover that on the rings that holds the shade on was cross threaded and the light socket was loose.  There is no way to remove the crossed threaded ring so I am missing a lamp shade.  Due to the size, weight and the amount of time spent setting it up and rearranging wiring and my desk, I decided to live with it.  It would be an insurmountable task to return the item due to the sheer weight of the entire lamp.  Otherwise I would love it If that lamp shade could be installed.