Hi, I used a great models from Hugo Groeneveld over at https://www.thingiverse.com/thing:3020026 to create an excellent side mounted spool holder with bearings for the K1 Max.

This model replaces the two back screws with (M3*10) for mounting. You can mount high by using top and middle screws or at the bottom by using middle and bottom screws.

You will also need 2 x 608 type bearings.

Updated: Added model with K1 Max logo and filament tube guide.

Updated: Added model with more support to filament roller area, also changed K1 and Creality font.

Updated: Added model as above but with factory spool holder mount.

Updated: Added model with built in spool and ptfe holder, doesn't roll as freely keeping the filament tighter preventing tangles. Hole is 4mm for ptfe tube, if you would like a fitting instead, you can drill it out and tap as required.