PTFE Joiner Box for Drybox Auto Rewinder

Update 11/7/2025 - Increased the bottom height by a decent amount so the back PTFE tube routing has less of a significant bend before it goes into the back of the enclosure.  This should help with alleviating friction on filament as it is guided through the PTFE tubes.  Uploaded these freecad files as “version 3” and updated the pictures to show this as well. 

Since I do not use the Drybox I needed a way to hold the PTFE connector against the top of the enclosure so it was not being held in mid air by PTFE tubes.  The magnets allow a very strong hold against the top of the enclosure so the part does not move or lift off the surface.  I originally designed this with (2) magnets but it was not strong enough.

Hardware Required

• (4) 6mm x 20mm x 2mm (6x20x2) magnets - N53 grade (the ones that Prusa uses in their MK4S printers)
  • Compatible with 5x20x2 magnets as well, however the magnet slot width is designed for 6mm so there will be a little bit of extra side to side room.
• (2) M3x10 socket cap head screws (use some from the spare parts in the Prusa kits)
• (2) M3nS nuts (use some from the spare parts in the Prusa kits)

Assembly

1. Insert the magnets into the slot openings (The chamfers help easier insertion)
   1. It is suggested to hold your finger over the slots while inserting one magnet at a time to avoid the magnet from popping out since they are in relatively close proximity of each other
2. Insert the M3nS nut into each of the openings on the sides of the bottom (see pictures)
   1. If necessary use a small allen key to align the M3nS hole with the hole of the screw
3. Insert the PTFE connector box into the bottom
4. Insert the M3x10 socket cap head screws into each of the sides of the top (see pictures)
5. Place the top onto the bottom and fully screw the parts together
   1. If the screw does not align with the M3nS nut please see sub bullet point of step 2 above
6. Put the assembled part on top of the enclosure (see pictures)
   1. Once the assembled part makes contact with the top of the metal enclosure the magnets will automatically lay completely flat since the magnetism is very strong.

Disassembly

1. Unscrew the top from the bottom
2. Take the PTFE connector box out of the bottom
3. Remove the magnets by taking a piece of metal and attracting the magnets.  They will pop out of the slot very easily but be careful attracting each other since the magnets can be brittle.
4. Remove the M3nS from the sides of the bottom
   1. Use a needle nose tweezers or a small allen key to push the nut out from the top of the screw hole
5. Remove the M3x10 socket cap head screws from the top

Printing

• PETG
• .20mm Structure Profile
• 20% Infill
• 100% Fan for the bottom and top
  • The small overhang for the M3nS nut in the bottom needs rapid cooling
  • The small overhang for the socket cap head screw in the top needs rapid cooling
• No Supports
• Directionality
  • Bottom - Print face up (The STL defaults to this on import)
  • Top - Print with the closed side on the print bed (screw hole inserts facing the bed, IE: upside down)
• Originally printed on a MK4S + MMU3 

The file name having “Version 3" naming implies there was a “Version 1” and “Version 2”, however I never published them because they were a sub-optimal part requiring to be printed at a complete 45 degree angle.

Since I do not use the Drybox I needed a way to hold the PTFE connector against the top of the enclosure so it was not being held in mid air by PTFE tubes.