Printrbot Brand Spool Spacer for Printrbot Simple Metal Spool Holder UPDATED

This is a spacer to center Printrbot brand spools of plastic for my Simple Metal Spool Holder available here: http://www.thingiverse.com/thing:322923
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Fits these roles of plastic: https://www.amazon.com/s/ref=sr_nr_n_1?rh=n:16310091,p_4:Printrbot,p_89:Printrbot,n:!16310161,n:6066126011,n:6066128011&bbn=6066126011&ie=UTF8&qid=1404111459&rnid=6066126011
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It should also fit any spools with an inside diameter of around 51.75mm.
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UPDATED 2014-08-04. I increased the diameter slighter a