Dual Internal Spool Holders for the Snapmaker J1S printer. Spools can be changed while the plate is in the Down Position or Full Up position. These have been in use for over 1,000 hours print time with No Issues.

There are Left and Right bowden tube holders that snap into the Square Holes into the inside of the rear panel of the machine, replacing the original spool holders... (note that this setup is designed so that the LEFT spool feeds the RIGHT extruder and Right to Left accordingly. This is used in conjunction on my machine with the J1S Top Extender that I designed (Also a Thingie File).

There is a central ribbed hub with bearings and then a variety of combinations of spring-tensioned cones and spacers that slide on to hold the spools depending on the center diameter of that manufacturers spool. The cones will slide on and detent into one of the many grooves and lock in place, holding the spool in a centered position. Tightening the nut on the end of the bolt will vary the tension if the spool is off balance and wants to free-wheel.

The Holders are held primarily by applying double sided Gorilla Tape to the upper back of the main plate (see photo), and also a small piece on the foot of the bowden tube guide that snaps into the rear panel.

These require (4) 608Z Ball Bearings (8mm X 22mm X 7mm) and (2) hex bolts/nuts (8mm X 75-80mm) and (2) of the small screws that hold clear side panels on get replaced with slightly longer ones that screw into the base of the upright side plate through the frame (unsure what size... tiny Metric). You will also need 60" of new bowden tube.

You will want 4 each of the "Short Hub V2" and the "Hub Spacer"... The "Long Hub V2" is a seldom used component only for deep recessed center spools.

The Cones DO NOT thread on... They are Push-On/Pull-Off with detents.
Removing spools is done by pushing on the center bolt with your thumbs and pulling back on the outer rim of the spool simultaneously.