Shrinkage calculation object

*EDIT*
Check out the new version of this tool at: http://www.thingiverse.com/thing:1982686
The new version is easier to measure, and the new spreadsheet will account for both shrinkage and radial compensation error.
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I've started using this thing to work out how much my materials are shrinking.

I'll run this part first on a new type of filament, plug the results into a google spreadsheet that averages out the error a bit, and get a scaling factor for my slicer (S3D for me) for a