Filament roll holder

This is a spool holder end cap. Well two of them really.

Perfect for the 30mm and 50mm spool inner diameters and when you're hanging your rolls on an 8mm rod.

The stepped sizes are designed to slip inside the spool core and lock it in place. The steps are at 30mm and 50mm so work with the cores I have here and any that I know off right now.
Should fit any of these:
https://www.idig3dprinting.co.uk/news/how-to-guides/3d-printer-filament-spool-sizes/

The advantage of these, especially the slotted one, is that it slips off quickly and easily when needed. Just loosen the nut a few turns and it comes off. When you want it locked in place though it's not coming off. Makes for quick and easy filament swaps.

Using a core like this makes sure the rod is in the middle of the core and this greatly reduces drag and skipping of the roll as the filament is pulled out.

The holes in the model make for a strong model. The many walls this generates remove any thought of crushing. The si