A three pieces support for a 40 mm fan, designed for my prusa mendel from makergear, because I was thinking the fan I mount before was to far from the printing piece and the hot end I made a cone for it to blow closer, it use 8 M3 bolt, I use 6 M3x25 and 2 M3x10.
The different pieces are, the support that go on the x carriage, and the support for the fan that you can rotate. See picture for better understanding.
Print the fan support support, there's two objects mirrored in the file.
Print the fan support.
Screw, that's it.
Update : Because of the pressure a very little amount of air go through the cone, it work for me (it's enough to cold a little and not to much the prints while not cool the hotend), but not for everybody so I post an update, the support fan bis, there less pressure, so more air go through, try and tell what you think.