Just finished printing my first own design!
The screw holes are too small, the fan itself is blocked and the nozzle would hit the print bed…
But hey, I made this. And as a software developer I’m used to debugging. 
Nice job!
I’m guessing you use OpenSCAD since you’re a software developer (as am I).
The holes on my prints usually come out a bit too small as well. It seems to be a common thing to either have the outer or inner dimensions correct. For now, I just fix up screw holes with some drill bits I have epoxied to (printed) handles.
@Carlton_Dodd yeah, I was thinking along those lines, too. But as I’ll have to print it again anyway, I’ll increase the hole diameter by half a mm. Oh and thanks!
@Carlton_Dodd yes, OpenSCAD it was.
My ideal program would be something with the point and click editing of Tinkercad or 123D, with the programmatic generation of OpenSCAD. Given that every time you open a project in Tinkercad, it quickly steps through all of your boolean operations, it’s probably generating a script in the background. How hard would it be to give everyone access to the full script for the part?
Cost to print first iteration: $XXX to $XXXX, cost to print N+1: practically free!
Adjust, print, release V1.01
Nice!!
Very cool! I imagine you’ll find that is too much “choke” on the duct. I printed out some similar ducts in various configurations and found that if the opening of the duct was less than maybe 1/4 of the size of the fan (diameters) then the back pressure reduced the air flow significantly (I had two fans of the same size, so experimenting was quite easy). Worth experimenting with.
@Carlton_Dodd , how do you affix the drill bits so they do not turn in the handles?
@Matt_Harrington
I epoxy glued the bits into the handles. They are older bits, but very handy!
@Michael_Vaughan that would be difficult. In my script I use variables to specify certain basic sizes and derive the details from them. If I were to grab some edge with the mouse and move it, how should that be reflected in the script? The position of one edge is often determined by more than one variable. As much as I like point and click, I still prefer the power of the script!
@Mike_Miller Thanks to Mr @Brook_Drumm it was only three Xes.
Love the gay color 
@Florian_Wallburg poor form.
@Florian_Wallburg me too.