There are many versions and remixes of this type of roller. This one is remixed from: https://www.thingiverse.com/thing:2693565.
I wanted to be able to print certain filaments while the filament spool resides in the dryer / dehydrator; this can be handy for very hygroscopic filaments like nylon. This remix is such that the filament roller fits inside my filament dryer / dehydrator while still being able to handle 1kg spools.
The original design is modified such that the filament roller base plate is higher and has a recess to allow the base to fit the filament dryer tray. Also I made two changeable spool adapters: the 'normal' spool adapter fits most filament spools (with inner diameter of ~52 mm) that I have and the smaller version fits spools with an inner diameter of ~ 48 mm.
More information about the filament dryer / dehydrator and the related dryer tray extensions can be found here: https://www.thingiverse.com/thing:2865085
The filament feeder (angled) is this one: https://www.thingiverse.com/thing:2116535
Assembly is self explanatory. You will need:
3 bearings, type 626ZZ
1 bearing, type 608ZZ
3 bolts M6 x 20 mm (or longer will work too)
3 nuts M6
I used this https://www.thingiverse.com/thing:1928974 and my vise to insert the 608 bearing in the roller. Make sure the bearing is flush at the top of the hole of the filament roller base plate.
Only supports are needed for the roller base plate. The rest can be printed without supports.
Print in PETG, ABS or anything that can withstand some heat.