Coupling for GREG spool for wide bobbin

This additiona part for spool of GREG filament manufacturer (St.Peterburg, Russia).
http://www.thingiverse.com/thing:3588186

I needed it because I bought a filament bobbin without spool of another production, and it turned out to be wider.
Adds 13 mm to approximately 22 mm from the original width without additional refinement of the original spool. if you modify the original spool, you can reduce the minimum width.