Summary

Two Piece Prusa Spool Holder based on http://www.thingiverse.com/thing:20663
Split holder to ptint on smaller bed, such as Thing-O-Matic.

Instructions

I am building my first Prusa using my Thing-O-Matic, however the bed on my TOM is smaller than the original design by QuantumConcepts. I had to split it up and join it with some 1/4-20 rod.
I have posted two different ends, one closed, and the other open. I found the open end easier to switch out spools. I have placed two 1kg spools on this and it holds, though I haven't finished my printer so I don't know how it will do in production.
I printed the parts with 15% infill, 0.30 layer height, 2 shells, 30m/s feed rate. Largely Mk7 defaults, although I recommend at least 2 walls for support.
BOM would include 2x 1/4-20 3" Rod, 4x 1/4-20 Nuts, 2x 1/4 Washers.

Prusa Simple Spool Holder Split