Screw spool holder

This is my remix/recreation of bolt/nut spool holder I've once made for my first printer - The Zonestar P802M. I can't find where I've got the original files, I just had printed one, so I've decided to make my own. The original piece was to long for me, so I've made my with some tweaks. Fits almost every 0,5 and 1 kg spools. It is 80 mm long (with 6 mm "big circle" on the side), half plain, half threaded with M50x4 thread. For the pivot I've used some threaded M8 rod.
I have plans to make an fi