CB1 heatsink 4020 fan mount

There are already very good alternatives available, but none of them seem to force the air flow on the fins of the BTT-made CB1 heatsink.
This version tries to make sure that all the air exits only through the fin channels (give or take) for maximum cooling efficiency.

4x M2.5*25 FHCS required for mounting the heatsink and mount to the board (M8P) assuming a 0.5-0.75mm thermal bad under the heatsink.
If using a 1mm thermal pad, do not over-tighten.

4x M3 3x5x4 heatset inserts for the fan mounting holes

4xM3*8 SHCS bolts work a charm for a Noctua fan, YMMV.

Printable without support when positioned “upside down”, layer height 0.3mm and low infill. Don't go too low with layer height as it may cause heat creep and clog at the end of the trip (many small filament extrusions and retractions).

For those wanting to go overkill and using a Noctua 4020 with PWM input on a Manta M8P, you can get inspired by the following klipper configuration (adapt the pins depending on where you plug it). The PID is somewhat stable while printing PETG, a bit watermarking when on idle.

[temperature_fan CB1_fan]
pin: PB9 #adapt this to where you connect on the board
max_power: 1.0
shutdown_speed: 1.0
kick_start_time: 0.5
hardware_pwm: True
#off_below: 0.3
tachometer_pin: PC15 #same remark as above
sensor_type: temperature_host #if present in your configuration, you have to comment the CB1 temperature sensor to use this configuration.
control: pid
pid_Kp: 0.5
pid_Ki: 0.1
pid_Kd: 2
pid_deriv_time: 10.0
target_temp: 43.0 #happily maintains it while printing at 20-30% duty cycle
max_speed: 1.0
min_speed: 0.1
#control: watermark
#max_delta: 5.0
min_temp: 0
max_temp: 90