The Alibre Design/Geomagic Design CAD file has 2 configurations for the spool holder and for the axis.
SPOOLCOUNT, SPOOLWIDTH SPOOL_INNER_DIAMETER and SPOOLDIAMETER specify the spools.
The axis has 0.5mm wider ridges between the spools to better keep them in place and have a tiny gap in-between the spools. This helps to keep one spool from rubbing on the next one and turning it.
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