Polymaker Rims and Spool Adapters (1kg)

Why Use Rims?

Printed rims improve the strength and reliability of cardboard spools.  They also prevent the buildup of cardboard dust that can interfere with material handlers.  

Which Version?

These models fit Polymaker 1kg cardboard spools.  In late summer/early fall 2024 the hole pattern on the outer edge has changed, though some old inventory is still hanging around.  The old pattern uses six slightly asymmetric holes.

I am currently aware of two new hole patterns (as of 11/15/24).  The first one uses 3 pairs of oval holes, and the second one uses 2 pairs of round holes.  My pattern for “new” holes will fit both of these spools.  

Printing

For the smoothest rims, I highly recommend using step files because they accurately model perfect circles.  An stl file approximates circles and the artifacts are visible at a large size.  Be sure to enable arc fitting (G2, G3 commands) if your printer and slicer support it.  

Fit and Tolerance

TLDR - There is no perfect fit, but it is good enough.

While testing printed rims on about 8 spools, I found some factors that can change how well they fit.  The edges of the cardboard are sometimes pushed out where they are cut.  This lip creates extra thickness that can make it frustrating to fully seat the rims.  Humidity can make the cardboard swell, creating a fit that is tighter than normal.  I noticed that one of my rims was very tight on a “wet” spool, but after drying the same rim easily slipped back on.  

Thanks for visiting, and enjoy!

Major update: Added files for the old hole pattern.

Minor update:  I adjusted the oval standoff near the inner hole to have a looser fit.  

Minor update:  Added another hole pattern for the “new” design after discovering it in my most recent order.