Printrbot Simple Metal Spool Holder w. semi printed ball bearing & thread lock

Even though there are many holders for mounting the spool on top of the Z-axis rods, I wanted to create my own variant. I had some metal balls that I wanted to do something with, so I integrated them in the spool holder. Also my first attempt at creating threads, got the clearance right on the first try!

The bottom part attaches to the printer rods and 6mm balls (you could probably print the balls as well!) fits in the groove. The spindle snaps on the pin, and the nut is used to hold the spool in position.

The design can probably be enhanced, if I have time I might look at it. Works fine as it is though! I have taken inspiration from other designs already out there.

UPDATE 150409:

• "bottom" has been updated so that the snap on knob is perfectly sized
• "arm_V2" has a protruding part to prevent the filament to fall off the spool when doing long travel moves or large retractions
• "nut_slim" is a slimmer nut for spools with smaller center holes
• "top_shorter" is a shorter spindle for smaller spools