Mini filament spool skrew for 8mm threaded rod

I remixed this for two reasons:
1. The original threaded skrew wall was too flimsy for my taste.
2. The center bore is too big for the 8mm threaded rod I use to hold my spools.

So I beefed up the width of the thread plus added an inner 8mm hole with support arms that incidentally also help stiffen it overall.

I am also attaching the CATIA source CAD file.
Refer to http://www.thingiverse.com/thing:293382 for the mating socket.