Very cool! The only thing that doesn't really fit is that little grip section...
Reminds me of a Porsche Design pen. It's called a Mikado, P3130. Do you know it? It's a ballpoint pen, the long rods have a small spacing - they probably sit in a ring groove and there is a tiny gap. The effect is that when the ends are pulled together there is a twist till the gap closes. I imagine there is an internal spring that does that. Of course there is a left and a right relaxation, i.e. a left and a right twist - and this advances the refill. I only saw it briefly at the last pen show I was at.
I like the design of your pen very much! Well done! Did you use SS bicycle spokes?