Parametric Spool Hub Adapter

Overview

Here is a set of different adapters for different types of spools, and the FreeCAD source to create them. A bit rough on the FreeCAD side, but it gets things done (mostly). (On other than Linux systems you might have to update the reference to the font).

The two main factors determining size are printed on the side so it will be easier to keep track of multiple adapters. Certain spools also have off-center hubs, and those can also be accommodated.

Printing

Measure the width of your spool and the diameter of its center hole, then pick an adapter that matches. If you have something not already covered add a row to the spreadsheet in the FreeCAD file and export a new one.

For any spool that is symmetrical you can print two of the same model. For the ones with offset centers you will need an “A” and “B” version.

Each adapter needs a pin. If you do not want to use 608 bearings, print a Pivot to use in its place.

Post-Printing

Fit either a 608 bearing or a Pivot into each adapter and secure by pushing an adapter pin from the other side until it is seated, holding the adapter tight against the center of the bearing or pivot.

Then fit a pivot/bearing into each side panel of a drybox and they should hold your spool in place and still  turn nicely. 

Updates

Jul 17, 2025

Updated to hold better if heat or age starts causing the cereal container to start bowing.

• New design with clearance for the pivot or bearing to be clipped in by the side panel.
• Adapter pin now clips in more tightly.