spool cone for filamentspool M8 nut screw Anet A8

I've created a pair of cones to fit into my filamentspools. They can be screwed into the spool with two M8 nut-screws and a piece of threaded rod. The outer nut screews are self-locking nuts.
The biggest diameter is 61mm and the smallest 40mm. The hight of the cones is 20mm.

The cones are optimised for Kaiserlich24 spools and the overhead spoolerholder for the Anet A8.
http://www.thingiverse.com/thing:1505075

They will fit to serveral other spools between 40mm and 60mm, too.
Also usable