One of a kind mechanical spool bushing that can retract and expand, also can fit on any kind of filament spool. However, this is just a mechanical spool bushing, mounted on any threaded rods of your choice, Just adjust the parameters and some other stuffs in the scad files to fit your liking and print away.

You can use any kind of filament stand with this, save more filament and not to mention, it is quite stylish and cool as well to have something simple, and mechanical properties as well.

The picture is an example of how it is assembled and mounted on your existing filament holder.

Please give me feedback.

What's needed:

At least 3-4 M3 x 16mm screw (for outer part)
At least 6-8 M3 x 12mm screw (for center part)
Threaded rod of your choice
2 nuts for the threaded rod of your choice

Print at least:
3 arms
2 center (of your choice)
3 holder (of your choice)

Put them all together like in picture shown, then the nut of each side of the threaded rod will be used to compress the mechanical spool bushing

One example of filament holder you can pair with this is http://www.thingiverse.com/thing:712159 but you just replace the spool bushing with mine

SCAD files:
Do change the parameters and values to your liking and experiment with it, I'm still new in openscad so you have to adjust one by one.
You have to reduce the arm thickness in its scad file if you want to thicken the holder