I do not have Ender3 any more. My thoughts after week or more of using this: -Cover does not need to be so big. This part can be easily removed and mounting points for part cooling fan moved to main part. Hot end would be better accessible and there is no need to cover it so much. On the other hand cover could be mounted with neodymium magnets. -Hotend cooling fan need cover. I accidentally damaged my fan with screwdriver too easy. If you are as clumsy as me and damage your fan then you can exchange it with motherboard cooling fan. https://youtu.be/WVlCcw_Ls6A - Assembling animation. Older version but still works. This is my attempt of ender 3 direct drive with clone BMG (Fysetc) and clone V6. I accidentally bought V6 without fan so i decided to make this with original fans. Its second iteration of this project and changes are based on flaws that i found in the first printed version that im using about several days. Nozzle is about 8-10mm before printer bed so printing Y axis is "shorter" about that value. This problem can be "fixed" by moving printing surface, changing home offset in firmware or just some slicer tweaks. With standard motor you will need new X endstop housing part. *Updated with new fan duct, lid part and some minor tweaks.* "GrillPart.stl" is supposed to be a modifier\part of LidPart in your slicer. With this you can make cover with infill pattern. If you add a part to lid in PrusaSlicer then grillpart should be placed automatically in right place. In other slicers you need to move that modifier in right place manually. Then you can rotate whole to right orientation. After that set per-model settings of GrillPart to 0 or 1 perimeter without top and bottom and adjust infill. For this thing you need additional screws.

For cooling fan:

- 2 * M3x12 + 2 * M3x19 OR 4 * M3x12

M3x19 will better hold the "lid" part from side
For "lid" front side:

- M2x(+9) with nuts

OR

- M3x(+9) with nuts

Holes are 3mm because i thought 3mm would be better but my M2 screw works good and they are smaller so used them. Check head size of your M2 screws or change holes size.
For main part:

- threads of original heatsink: M3x12 with nut

optionally two screws with nuts, more info below

- thread of original hotend housing (looking frontside left one): M3x9

for second thread you can useoriginal screw
For new X endstop housing:

- M3x19

its possible to use longer screw but it requires modification in model

Isolation cotton from upper side of heatblock may be required! Original blowing fan duct works. Fan is mounted with original ender 3 screws. This cable chain https://www.thingiverse.com/thing:2920060 will work with this design.

Found 191 3D-models for “BMG clone” across many websites

Bondtech Filament Guide

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BMG + V6 | Ultimaker Direct Upgrade

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BMG Clone Push fitting fix

BMG Clone Extruder Fix

BMG Aero Direct Extruder

Ender 3 BMG V6 clone with creality fans

UM clone BMG + E3Dv6 carriage (Now with mounts!)

BMG-X2 Chimera Creality Ender 5 Extruder Mount

Ender3 direct extruder modification