i originally designed this spool holder for a Creality machine. i recently made new parts to work for the A1 Mini EXT spool. this was absolutely necessary to print TPU 85a without the extruder slipping. this accommodates many different ID spools and can quickly be placed or removed by at most ⅓ rotation of the spool nut. i hope this helps many of you get better use out of the EXT spool placement or on any printer.
the image show the rev 002, lower mount on a Bambu Labs A1 Mini.
you will need a 5/6 x 6" bolt, nylon nut and two 608 bearings. tighten the nut until the desired drag is achieved. then put a dab of glue on the cover.