Wall Mount Spool Holder for Large Spools and Akro-Mils Rail

When you build a Voron (or buy/build any large/fast printer), you may find yourself needing to order larger quantities of filament on bigger spools than you did previously.  I needed to use a 3kg spool of ABS from Polymaker on my 2.4, and there isn't much available in the way of a spool holder for 3kg to 5kg spools that mount directly to the machine, which would work with where I have mine positioned.

I found a few wall or ceiling mounted options, but in the location where I wanted to mount my spool, I already had a section of rail mounted which was intended to hold a couple of Akrobins which I was no longer using there.  So I designed a spool holder which mounts directly to the rail, which I am sharing here because it seems like the sort of thing others might find useful.

You will need to print a right and left arm, and there is a brace which runs between them holding them together using 4 M5x20 BHCS threaded into heat set inserts.  The brace probably isn't absolutely necessary, but I think it makes for a more solid installation.  The cross-piece (spool axle) is a slip fit into the notches in the arms.  I like the Voron style of spool holder with a length of 4mm PTFE tube, so that's what I used.  This seems to provide about the best compromise between smooth function, and preventing the filament from getting loose on the spool.  I used one of the ball bearing type spool holders on another printer and found it to move too easily; the spool would get moving and overtake the filament, which led to some problems.  The PTFE tube is simple and relatively foolproof.

This spool holder will fit both 3kg and 5kg spools from Polymaker; for other filament brands your mileage may vary.  Looks like it will also hold 2 normal 1kg spools if that's what you want.  I printed it out of Polymaker ABS on my Voron 2.4 using a 0.6mm nozzle, with 4 perimeters and 20% infill.  There are “mouse ears” already built into the files to prevent the parts from warping up off the print bed.  I am including the stepfiles in case anybody wants or needs to alter it.

One last note; the parts will print best with your perimeter generator set to classic mode rather than arachne, since arachne will take a shortcut around the internal corners where the axle sits in the arms.  The parts will work either way, but I added features in the cad to trick the slicer into making true square corners in those pockets, and use of arachne will negate that.

Amazon link for Akro rail:

https://www.amazon.com/gp/product/B000EFPI94/

Assortment that the M5 inserts I used came from:

https://www.amazon.com/gp/product/B0B46YBNV4/