Being or having an enquiring mind I looked up Ted Schimmel,s u tube video re The Little Giant Pen Kit. It uses a Parker refill. The end presses in for good,the tip has a screw in to press first then load the refill and screw the tip on.This tip piece is not obvious at first if pressed together it can jam the threads. The pen is 4.5 inches long and 5.25 inches posted the preferred used position .Takes an 8 mm or 5/16 drill for the brass.Weighs an ounce. Same bushing either end for turning. My comment re turning I would turn to the round ends not below but above and before the top of the rounds. Comes in Gunmetal, Chrome and Antique Brass. Most useful. I like your pen.
Peter.