13 August 2018
I have printed one for myself and tested. It fits perfectly. The original m4 screws from the stock spool holder can be recycled and used to clamp the spool holder adapter V2. The z-rod holder works as well and I have inserted a 608 bearing to hold the z rod in position. Next I will print the other spool holder parts and mount it on top.
11 August 2018
I have just realised that the z rod is slightly higher than the top 2020 frame and hence a slight modification to the adapter, name ending V2. Now you can insert a 608 bearing to hold the z-rod in position.
10 August 2018
I have just designed this at my work place and have yet to print one for myself to test. This is a spool holder adapter to allow the spool holder and filament guide to combine as one.
The aim is to use 608 bearings to reduce the fraction generated as the spool turns on the stock spool holder that comes with ender-3. So instead of sliding, now it is rolling and it allow the filament to be fed into the extruder more easily without having to exert too much force to pull it.
The problem I had with the original spool holder is that when the spool is new or the spool hole is smaller, the filament spool cannot roll freely on the spool holder. Instead it depends on the extruder motor to pull the filament. This has resulted in some region of the print being under-extruded. This weaken the print and wasted time and material.
I had remixed this from the spool holder adapter that I designed for CR-10.
Installing the adapter should be easy. I have designed this to slide in from the top left hand corner of the 2020 aluminum extrusion. Then, the spool holder should be mounted first. To prevent the adapter from moving, there are two 3.5 mm holes to allow you to secure the adapter to the 2020 extrusion with t-nuts.