Universal spool holder with 608zz bearings for bigger spools

I was inspired in Artur Sass Braga's “Central filament spool axis…” design in which I found that its nut is very small for spools that have inner diameters larger than 63mm, so I redesigned it from scratch and created two versions of nuts:

• The smaller nut: which can handle any spool from 35 to 65 mm of inner diameter.
• The bigger nut: for spools from 35 to 75 mm (like Sunlu's spools)

The axis measures 90 mm and you can insert 608zz bearings on both sides. The inner hole is for an M8 screw to mount the whole thing.

Be advised that this was completely redesigned, so these threads doesn't work with Artur's design.

Let me know in the comments if you need a nut with a particular size.

About the tolerances…

All the parts were designed with their proper tolerance values so they could fit, but I've included a pair of test designs so that you can print them according to the tolerance values that your printer requires. 

In my case, I've sliced them using -0.2 horizontal expansion for the nuts and -0.1 for the screws, but that's how my printer works. You've better try your own parameters with the testing models.

Changelog :)

29/mar/25: 

• Added a 60mm long axis, as required by @MattyNic_3080557 
• Did some fillets on the nut's edges as suggested by David Williams to reduce its sharpness (find it as V2).