Simple filament spool holder

Yet another filament spool holder...

I was looking for a filament spool holder that fits my needs:

)fits >2kg spools
)still compact
)simple
)yet with ball bearings --> friction test: http://gph.is/2lKmGoh
)and adjustable friction

Considering the huge amount of spool holders here on thingiverse I was quite amazed not to find one that is just perfect for me. So I designed this. Due to it's simpleness it's a bit wobbly but it does the job.

Additional stuff you'll need:

)8mm threaded rod
)2x 8mm nylock nut; alternatively 1x nylock and 1x normal nut
)4x 8mm ball bearing
)a pipe wrench for drilling the rods into the holes (should be tight enough to prevent the need of further nuts)

Perhaps the holes in the spool holder are too loose with your printer's tolerances - if that's the case, please tell me and I'll decrease their size.

edit:
Just a warning!

This design is flawed. After using the spool holder for some time now, I have problems with the thread of the