This is my first attempt at an upgrade to my Printrbot Play's Spool Holder, it adds two 608 bearings to the inside of the spool, on top of the existing spool holder, allowing the spool to spin more freely and not cause large lines up the z axis hopefully.
After printing you'll need to add:
x2 608 Bearing
x4 M8 Washers (one on each side of the bearing, inside the arches)
x2 M8 1.25 x 25 Hex Cap Bolt
x2 M8 1.25 Nut (Possibly optional as in an initial test I was able to thread the bolt into the print)
The file ending in full holds two bearings with a connecting spacer between, the other file is essentially half as it holds a single bearing for a slightly more modular spacing for different spools
Added file - Key
The Key slides over the nub on the stock Play Spoolholder to help keep the spool from working it's way off the holder.
Key prints with the Hole at the top, I used a brim, 10% Fill, and 0.3mm layer height for speed
Update March 5, 2016:
Added a clip to hold everything in place. As it is it's a snug fit into the spool holder upgrade, and therefore you might need to scale it down just a hair in one dimension or sand/file it a smidge. For me, it was just a bit of a press fit and then slide the assembly onto the existing spool holder bracket on your printrbot play. Place your filament, and then lock it in with the key.
I did three shells (1.2mm thick walls) as well as the same for the bottom/top thickness