Update 24May2021 Added a Hex Shaft, Hex Shaft End Cap, Bearing, and Bearing Extended. I didn't like having to purchase the threaded rods so I created a hexagonal printed shaft for the spools that is 90mm as opposed to the 80mm of the threaded shafts from amazon. They are meant to be printed laying down (hence the hex shape) because printing them vertical results in shafts that break at the layer lines regularly. They have a slight detent at each end which holds the Hex Shaft End Caps in place preventing them from falling off while putting the filament spool in the box. Being longer helps keep the box at the proper width as well. The plastic bearing replaces the purchased 22mm bearing and I have now used them for over a month with no issues from friction. I printed in PETG so I am not certain if another filament would have different results. I was not happy with the bearing since it resulted in wobble of the Hubs if it were placed in a larger hole. I designed the Bearing Extended to take care of this problem and have been using it for a couple days.

I have experienced a few problems with the passthroughs if the filament is pulled at too tight an angle it binds at times. As a workaround, I simply place the box across my desk from the printer to keep the angle relatively strainght. As a result though, I am designing a new passthrough that will allow the pneumatic connector to be used with a tube to better control the filament. Should be within a couple weeks.

Updated again. The Shaft Plates weren't printing well with no supports. I have re-modeled them a bit and now there are only a few strings. None if you print them with a 0.12 layer height.

Filament Dry Box Set (Updated 3/11/2021)

This set of prints are designed for use with the following items to create a very slim box that will hold ever 1kg spool I have used so far. It will rub slightly with the YOUSU spool but it still works fine. Care must be taken to center the side walls or things will not work out. I have included an indexing tool that currently ONLY works with the earlier version (not V2) side wall holders. I will update that as soon as time allows and it ONLY works with the cereal box I have listed. You may be able to use these with others but the spacing may be different.

All of the box parts are designed for PLA, 4 walls, 4 top and bottom layers with 25% infill and print pretty quickly.

The hub is best printed in PETG but will work in PLA for the larger diameter spools. If compressed to the smaller diameter spools, they will break.

If you have a different box you would like a design for and are willing to send one to me, I could update the designs.

https://www.amazon.com/gp/product/B07K3TPQ86/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&th=1

https://www.amazon.com/gp/product/B07THYZ4DB/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B08JQ78L8C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

This is a clean sheet design but it was inspired by several things on here. Most notably

https://www.thingiverse.com/thing:4716425

None of which could accommodate the two extremes in spool hub diameters I have. I have Yousu (pretty good PLA) with a diameter of about 51mm and I have Sunlu with a hub diameter of around 74mm. The conicals did not work, either stuck out too far to fit in my cereal boxes or passed all the way through the hub. I didn't want a ton of different ones lying around. I wanted one to rule them all (at least all that I currently have). Squishing it down for the 51mm hub was not the easiest, but it wasn't rocket surgery either. UPDATE printing the hub in PETG makes for a much more manageable spring and has worked in all of my hubs.

Designed in Fusion 360 (files available if needed)
It prints without support, But there will be a few strings in the center. Normal support removes easily there.
It is designed for a 22mm bearing and 8mm nut on threaded shaft.
Nut will sit flush with outside of the adapter which only protrudes 3mm from the side of the hub.
It is a PETG spring. It works in PLA but is best if used with larger diameters as wrapped into a 51mm hub, the PLA versions I have broke within 2 weeks. No effects were seen on the 74mm Sunlu spool. As always, in progress. Use at your own risk.

Let me know how it works!

After doing this in PETG finally, the results are much better.

Hope it helps someone

Parts

Universal Spool Hub Adapter - works with all of the diameter hubs for 1kg spools that I have found so far. Let me know if you find something that doesn't work.

Sidewall Shaft Holder - When attached to the box sidewall and used in conjunction with the Shaft End Caps, provides a very slim holder that prevents the box sidewall from flexing and dropping the shaft.

Side Wall Index - Works ONLY with the same cereal box as mine to place the Sidewall Shaft Holder at the proper height to hold all of the filament spools I have come into contact with. I am currently redesigning this and if you provide me with measurements, I can design one for any box you choose to use. I am thinking of making a parametric version of this you can choose your height of.

Shaft End Cap Short (normal) and Tall - Attaches to 80mm m8 shaft and prevents shaft from slipping out of the Sidewall Shaft Holder.

Filament Passthrough Bolt - A cosmetic remix of the bolt found in the referenced THING.

Filament Passthrough Nut - A cosmetic remix of the nut found in referenced THING.