Broken truss rod repair :: 1960's Silvertone 1488 Silhouette

While attempting to correct the excessive relief in this neck I was surprised to find that the truss rod nut was missing.  My guess is that it was overtightened and snapped off a portion of the threads at some point.  Upon researching I was pleased to find that Frank Ford over at (and Gryphon of course) had made a post about a Harmony Sovereign with an identical removable truss rod.  I cut away enough material around the washer collar (pictured resting on the fingerboard above) to get enough grab with my pliers.  Once the collar was removed, I used hemostats to pull the rod free from the neck.  The truss rod was set quite far into the neck, leading me to believe that a portion of the threaded rod was in fact missing.  I'll need to source a new nut, shorten the upper bar and extend the threads on the lower bar before reinstalling.