This is a remix of the lock ring insert that ends up being flush with the spool vs protruding out. Josh-3D approved me posting this as long as I linked back to his original model which I'm more than happy to do since it's the best reusable spool I've used.  This fits his Version 2 spool that uses lock rings.

His model can be found here: [https://makerworld.com/en/models/868744-reusable-spool-for-bambu-refills#profileId-1189294](https://makerworld.com/en/models/868744-reusable-spool-for-bambu-refills#profileId-1189294)

I found adding a little weight to the spool helps it dramatically when being used near empty in an AMS. I used Josh-3D desiccant lock ring originally, but then I started storing my filament in dry bins and the spools have to sit right next to each other otherwise they don't fit so I modified the desiccant lock ring to sit flush. It does need a new lock ring tool, but it's super simple.  There's also 2 covers, a vented one for if you want to put desiccant inside or a solid cover if you just want to put weight inside.

Here you can see the dry bins I use and why I needed the spools to sit right next to each other: [https://makerworld.com/en/models/1120245-ultimate-ezystorage-dry-bin-desiccant-holder#profileId-1118485](https://makerworld.com/en/models/1120245-ultimate-ezystorage-dry-bin-desiccant-holder#profileId-1118485)

No supports needed. Would recommend not printing with PLA if you ever dry your spools since it has the lowest softening temperature. I printed mine out of ABS or PETG.