Filament Spool Bracket Assembly

The stock filament holder is simple and functional. The filament, however, doesn't play out smoothly because the spool simply sits on the support without the benefit of a bearing. In order to rotate it must regularly overcome a small friction, and as a result the filament plays out in starts and stops.

[I'm sure you've noticed this during printing. The extruder stepper pulls on the filament and finally overcomes the friction of the spool against the support so that a small amount of filament can play out; the same pattern is repeated a short time later. I'm not claiming that this produces artifacts, but it is such a simple thing to fix that I believe its worth the effort to ensure that you've created the smoothest and most efficient filament feed system possible.

See the Extruder Bundle Strain Relief as well.]

Creality supplied a folded metal bracket that mounts solidly to the top 2020 extrusion of the frame; a 32 mm diameter plastic shaft mounts to the top of the metal bracket. The purpose of this mod was to replace the 32 mm diameter plastic tube with a metal shaft, printed hubs and a pair of common bearings.

For this mod, you'll need the following printed parts:

 
Quan
Part
 
2
Spool Hub
 
1
Cantilever Block
 
2
Shim

The following prints check the fit of the corresponding printed parts before committing to the "full" parts above (to save time and filament):

 
Quan
Part
 
1
Spool Hub Fit Test
 
1
Bearing Fit Test
 
1
Thread Fit Test

You'll also need some hardware:

 
Quan
Part
 
2
608zz Double Shielded 8x22x7mm ball bearing
Amazon Link
 
1
8mm / 5/16" x 145mm threaded rod
 
3
8mm / 5/16" washer
 
3
8mm / 5/16" hex nut

 

Download all STL models and Fusion 360 Archive as a single zip file.


20181113 105911
Fig. 1

Shown here is the disassembled Spool Bracket Assembly.

Note that the bearings are placed into the hubs from the outside surface; this ensures that the shims hold each bearing in place within the hub and eliminate the need for any type of press fit or adhesive.

The length of the threaded rod is ~145mm.

The cantilever block is 35mm thick (at its widest point) to support the threaded rod, including an 8mm thick pad to widen the face and resist the tortional force of the cantilever load.

Note that the 30mm thread is printed onto the cantilever block. (This worked well on my Ender 3 with a 0.4mm  nozzle. The stock 30 mm plastic nut threaded onto it without issue.)

20181113 110030
Fig. 2

Shown here is the assembled Cantilever Block with the  8mm / 5/16" threaded rod. The length of the threaded rod is ~145mm.

The threaded rod is held in place by a nut/washer pair on each side.

20181113 110207
Fig. 3

Shown here is the assembled Cantilever Block with the  8mm / 5/16" threaded rod inserted into the Creality folded metal support.

The stock 30mm nut (black) is reused.

AsmFront
Fig. 4

Shown here is the assembled and mounted Filament Spool Bracket Assembly the front.

You can see the Cantilever Block; it is placed in the web of the vertical support, then secured with the stock 30mm plastic nut.

You can see spool hub, bearing and the shim against the inner race of the bearing. This is to ensure that there is no friction against those parts which are supposed to reely rotate.

AsmRear
Fig. 5

Shown here is the assembled and mounted Filament Spool Bracket Assembly from the back. It's identical to the front, including the shim against the inner race of the bearing.

Since there is no rotation imparted to the nut as the spool unwinds, simply hand-tightening it works just fine.

TestFits
Fig. 6

In order to minimize wasted filament, I provide three small test print models. These enable you to check:

    1. the fit of the bearings within the spool hub;
    2. the spool hub within a standard filament spool; and
    3. the fit of the 30mm plastic nut on the cantilever block.