Supply3DPLA spool spacer

Just a simple spacer for the spools from http://supply3dpla.com , as they ship december 2011.

I'm starting to run out of 608 bearings, so I tried to just use a 8mm hole in the middle and thread it directly onto the rod, and it works surprisingly well.

Still, I have only used it for a week, so I don't know how it holds up in the long run.

If you want a version with a bearing, check out this thing: http://www.thingiverse.com/thing:14238