MMU variable wall spool holder system

I like the idea of wall mounted dryboxes to save space, but they cannot hold large 2+kg filament spools with 30cm diameter. I also don't like the fact they are fixed to the wall behind the printer which is not very comfortable. So I created more variable system, where you can combine both Prusa dryboxes and simple open spool holders of various sizes according to your needs by simple hanging them on the rods.

System is fully customizable, OpenSCAD sources are atached. 

For printed threads I'm using great metric thread library by Dan Kirshner: https://dkprojects.net/openscad-threads/ (GPL licensed threads.scad).

Rod holder

Depending on particular threaded rod type and wall type you will need to use 3 or more rod holders. For sturdy steel M8 threaded rod, 3 are enough.

Extra parts:

• 2× 1 meter long M8 threaded rod,
• 12-20× M8 nut (4× for each printed rod holder),
• 6-10× 4mm screws with flat head (type depends on surface you will mount the holder on),
• (optional) 6-10× large M4 washers with 12mm outer diameter (to more evenly spread pressure on printed part)

Printed parts:

• 3-5× spool_wall_mount-rod.stl

Print settings:

• it is good idea to use more perimeters (3+)

Instructions:

• fix printed holders on threaded rods using nuts (evenly spaced),
• fix completed holder to wall in appropriate way depending on type of the wall.

Drybox hook

It is intended for use with Prusa dryboxes (https://www.prusaprinters.org/prints/4603-wall-mounted-drybox or https://www.prusaprinters.org/prints/4605-wall-mounted-drybox-with-sensor). You can use either 4 or all 6 mounting holes in drybox.

Extra parts:

• 4× M4×14 mm screw with flat head,
• 4× M4 nut (standard 6-sided)

Printed parts:

• spool_wall_mount-hook.stl

Print settings:

• use more perimeters (3+)

Instructions:

• drill 4 of the marked holes in the back of drybox (upper and bottom row),
• place nut in the hole in the hook, hold it with finger and screw the drybox with M4×14 screw,
• placing nut under the hook can be little tricky, I used small pliers for this,
• repeat for all drilled holes

Spool holder

There are 2 basic sizes of the holder, depending on spool diameter either 20 cm (up to 90 mm wide) or 30 cm (up to 105 mm wide). Both can be used for smaller spools as well (minimum spool diameter is 16 cm for both holder sizes).

Extra parts:

• 4× 625 ball bearing
• 4× M5×14 mm or longer screw with flushed head,
• 5× M4×20 mm (12 - 25 mm should be ok) with flushed head

Printed parts:

20 cm size:

• spool_holder-20cm.3mf (or spool_wall_mount-hld20-a.stl + spool_wall_mount-hld20-b.stl + 2× spool_wall_mount-roller20.stl)

30 cm size:

• spool_holder-30cm-left.3mf (or spool_wall_mount-hld30-a.stl + 2× spool_wall_mount-roller30.stl),
• spool_holder-30cm-right.3mf (or spool_wall_mount-hld30-b.stl)

Print settings:

• use more perimeters (3+),
• use 200 µm or smaller layer height to have reliably printed M4 metric threads,
• for rollers use seam position: random to prevent “bump” on the roller caused by the seam,
• for 30 cm version, disable skirt (holder is too large and there is not enough space for skirt)

Instructions:

• first screw in M5 screws into larger holes in both halves (they will serve as bearing axis),
• place larger (a) part on the desk and place bearings on the 2 M5 screws,
• place the rollers on the bearings and place bearings in top of the rollers as well,
• place second half (b) on the top with M5 screws going through bearings and align both parts,
• screw in 5× M4 bolts