CR-10 40mm stock hot end fan mod

Hopefully this is accurate as I made it from aluminium in my workshop and then came back to my PC and drew it out from memory.
The idea is that it will block some airflow from the bottom of the fan and therefore will not cool the heater block, you may even be able to run without a blanket on your hot end.
If you're 3D printing it ABS would be recommended although with a fan blowing on the part nearest the hotend you may get away with PLA.