Pen Wire Guide

I've recently got into wiring some coils for metal detectors and the likes. Some of the coils don't require any thing special while others can be vexingly complex.
Suffice to say working direcly off the spool just wasn't working for me. There were a bunch of old pens laying around and 20 min later one of them had been repurposed!
The stl has support material built into it to help with the end being tapered.
I currently have two spools of magnet wire the one pictured is rather stout the other is much longer. Both were taken into account in the design so there is a decent bit of flex.
Short spool ~50mm,~40mm
Tall spool ~45mm,~60mm