Of course the ur-lightbulb is the UK model with the bayonet fitting. This is known as the traditional lightbulb. When held in the mouth while climbing the stepladder it becomes oral tradition.
When the lightbulb travelled to the Americas it acquired a screw thread. This is the revivalist lightbulb. Of course once it is switched on it becomeselectric and outside the scope of the Mudcat.Torches were introduced for travelling folk and bluespersons to see to ride the rails. As most of them were blind, it didn't matter that they couldn't switch them on. Some people believe Cecil Sharp invented the lightbulb years before "Eddie" Edison (where were you, Eddie) Some people believe that oil lamps are the only true light,these are bluegrass or country lights.
Candles, on the other hand, are Celtic.
What do you mean thread creep? I may have had too many Fast Eddies or was it the mushroom omelette a la Kersey?