PolyDryer Filament Dry Box Center Bearing Shaft-Uses 608zz Bearings

PolyDryer Filament Dry Box Center Bearing Shaft-Uses 608zz Bearings

I designed this bearing assembly to be able to feed flexible filaments and nylon's from the PolyDryer PolyBox, with significantly less rolling resistance than the stock center tube or even the questionable quality bottom rollers would provide. In my experience the bottom rollers were of poor quality and were susceptible to increased filament friction if the spool edge was anything other than perfect. This is designed to fit Overture's cardboard spools, although other spools may fit. If you modify the STEP file to work with other spools, please upload a Remix of that file so others can benefit from it!

Build Details:

• Materials Needed:
  • (2) 608zz bearings per assembly
  • (2) 8mm or 5/16" washers
• Filament Requirements:
  • You NEED a filament that can withstand the dryer's internal temps without warping or deforming. 
  • PC is recommended, although fiber-reinforced Nylon may also work well, just be aware of the potential for creep to occur
  • Do NOT print this in PLA and expect to use the dryer with it inside. Just don't….please
• Print Details:
  • 3MF file is attached, for anyone who wants pre-loaded settings for PC
  • Walls-4
  • Top and Bottom layers-4
  • Reinforcing modifier on the bearing stems for 100% infill zones, extend in to main body for extra strength
  • Infill-25% rectilinear
  • Cooling-15% max (Prusa Core One) with Overture PC Professional
  • Chamber temp-min 40C

• Assembly Instructions:
  1. Print 2 of the side pieces and 1 center axle, then remove all supports when complete.
  2. Add a single washer on one of the axle studs, then press on a 608 bearing. The bearing should be a snug fit and be retained. Ensure smooth movement after installation. Repeat with other side.
  3. Place the center axle through the spool, then orient the spool in whichever direction you would like to optimize filament feeding.
  4. With one hand, align one of the side guides with the bearing on the axle, with the thin side facing upwards. The bearing should rest in the cup created by the side bracket. Repeat with the other side. 
  5. Guide the brackets into the grooves in the box until they are started and run true. 
  6. Press on the tops of the brackets until both bottom out against the center rib in the box. 
  7. Spin the spool to ensure nothing is binding and confirm operation. 
  8. See directions below. 

If you do decide to print this, please leave a comment at least so I know the design is working for other folks too! 

If you have spools of other widths and would like custom center spindles designed, let me know and I would be happy to do so as time allows. 

Only STEP and 3MF files are included, because this is 2025 and STL files are antiquated and hard to modify. Join me in helping to make STEP files the new standard for 3D file sharing. STEP's are included for ease of resolution control, and for anyone who would like to import this design into your own CAD software to remix as you like. Let's make the 3D printing world better for all of those folks who are involved!