These designs are based on these cereal boxes, which are the cheapest I could find. ᐰt the time of uploading this, they are currently $15 for a four back. With all the filament it takes to complete these, that's a grand total of about $5 per box!
I wanted to make myself some dry boxes I could print from, but didn't want to drill a bunch of holes and have to purchase bearings and screws and other hardware, so I designed this. The base slides down to the bottom of the dry box and is sealed up like a bowl, so you can dump in some loose silica beads to keep your filament dry long term. Just put the cross bar inside your spool and lower the whole thing down onto the mount. They roll really easily while printing.
I included two types of caps, so you have options for different filament tube angles. They both fit standard 4mm OD Bowden tubes fairly snugly, so it won't wiggle out. The angled one may need the hole slightly cleaned up, depending on how cleanly your print lays it. You can either print the gasket out of TPU or use the one that came on the container. I chose to just use the container's included one. That'll lock the cap in and create an airtight seal. Just open the pour spot and drop it in.