This is a Remix of various projects i found here… it is short and i think more usefull and strong to have the filament spool in a better position…
You can mount it directly on the Bambulab X1 back side (instead on the original metal support) or mount it on the rounded arm to move your spool on the left side of your printer.
You need two M3x16mm screws and two squared M3 nut (5.5x5.5x1.8mm) to fix the support to his arm.
You need also two M3x12mm screws to fix the arm to the printer (or to fix the support directly to the back side of your printer if the arm is not used)…
You need to buy two ball bearing at this link (or similar)
https://amzn.eu/d/fX8sRgL