I have a MendelMax 2.0 printer, which, like several other printers, is built with an extruded aluminum frame. One of the great things about these extruded aluminum frames is that you can easily attach things to them using bolts and T nuts. So why not bolt a spool holder onto my frame? I created this spool holder to handle 1kg spools. The two bearings allow the spool to rotate freely and very smoothly. I've tested this with Ultimachine 1Kg spools, and it works with either orientation of the spool. I have not tried with other makes of spools.Print out the part as shown in the photo, and oriented in the STL file. You'll need the following hardware: Place one M8 washer on each side of a 608 bearing and place into the slot as shown in the photo. You can insert the M8 bolt through the large hole on eaither end. Fasten in place with an M8 nut, as shown. Insert the M5 bolts into the spool holder from the front, and then add the M5 T nuts to the back, keeping them very loose. Finally, slide the T nuts into the beam's channel and tighten.