All you do is cut nock and uni bushing off, then take a dremel tool with cut off wheel and cut shaft down the middle from top to bottom.. insert the short piece of hollow threaded rod(from lamp building kit) by prying shaft open with big screwdriver, drive down in shaft with small hammer leaving enough to attach lamp socket.. do the same to the bottom of shaft where arrow goes into deer skull, drill hole in skull with 25/64 or 27/64 wood bit making sure to not wobble and get it straight up and down..to secure the shaft in skull you can put some 3500# epoxy on shaft and slide into hole or if you got a rally good fit you can use gel super glue and let it run in hole around edges..
if I didn't explain this well enough can take pics but its pretty easy.. you can get the extra threaded rod at Ace hardware, Menards etc..I used a 2216 shaft for lamp post so if you use something different will require different drill bit..