BuMat Spool fitting

Outer diameter - 57.5mm
Inner Diameter - 32mm

Made to fit this thing, *Printrbot Simple Metal - grip with spool holder http://www.thingiverse.com/thing:446649

Print with 2mm brim to prevent the part buckling/lifting up from print bed and set slow travel speed for a smooth inner circle finish.
I use a Printrbot Simple Metal printing PLA and set my travel speed to 20mm/s and got good results, no need to remove the brim afterward.

I left the construction lines in place inside the .dxf file if you want to edit the part.