There are a lot of great spool adapters on the internet. A LOT. Too many. To the point that I wondered why everyone has a model for “<this brand> spool adapter” and “<that brand> spool adapter." There are some okay models for reusability, but there are two problems with most of them for me: 

• I don't know what the dimensions of my spools are by looking at them
• After they are printed, it's hard to know which adapter is which

To fix these issues, and to eliminate the need to keep dozens of 3MF files, I have created Paraspool: a fully open, fully customizable, parametric spool adapter. 

What makes Paraspool good? 

• LIke most of the models out there, it aspires to be as filament friendly as possible (~10g per adapter)
• It has presets for common spools - Right now it supports Polymaker, AICOPYTO, Inland, Elegoo, and Overture spools perfectly (and others as well as possible)
• It has handy nameplates for each manufacturer, so you know which ones to grab when you need them
• Because it is parametric, it is fully customizable!
  • If you want, you can omit the nameplates
  • You can specify any size spool you like
  • You can specify any name you like
  • You can tweak the tolerance values to suit your printer's dimensional accuracy
• IT IS FULLY OPEN SOURCE - https://github.com/bmelton/paraspool

The rim adapter is defined in OpenSCAD, and the source code for it is on Github under the MIT license. STL artifacts are licensed under Creative Commons. This means if you want to add a preset, or change the font, or submit a batch of spools, you can! 

Reasons not to use Paraspool? 

• It doesn't support RFID within the rim adapter yet (I use RFID in the spool, but not the adapter, so this has been deprioritized, others might want their RFID tags in the rim)
• It might not yet support your spool adapter (but you can make a pull request)
• Some of the custom spool adapters are really custom to the brand, and might offer anti-slip or other custom capabilities that a universal solution cannot easily accommodate

With a little community participation, this could be the last spool adapter anyone ever needs.

A note about eSun spools

I got a bunch of help from redditor /u/5skinnn on the first version of eSun spools, but he reported irregularities and inconsistencies with the physical spools. To verify, I ordered some myself, and it's worse than you could imagine. Rim sizes are not consistent at all. Even on a single spool, I am seeing rims that deviate from each other by more than 1mm. 

I added the new (larger) eSun spool as it respresented a net new outer diameter, but in my opinion anyone who promises you a bulletproof eSun rim adapter is lying, and both they and eSun spools should be regarded as feral. 

A note about all spools

It's worth pointing out that the purpose of this project is to accommodate cardboard spools that enclose and ensconce hygroscopic materials. Cardboard itself is hygroscopic, and will absorb moisture. When it absorbs moisture, it will change in size and dimensionality. There is no avoiding this.