-I printed it with PLA, on the the STL position, without any support type.
-Heat a M3 nut and put it into M3 housing. Use a M3x20 or larger screw for it.
-Fix to the extruder body with 2 M4x20 or larger screws.
-For 40x40x10mm fan i am using 4 M3x10 screws without nuts needled (screw directly to plastic)
NOTE: after several ABS prints the support deform due to heat. I've reprinted in ABS :)