This is a thrust tube for a Dr. Mad Thrust 70mm EDF and designed for high speeds
(I'm not an aerospace engineer, but i tried to design it as good as possible, and after schübeler's description on their website: http://www.schuebeler-jets.de/en/edf-know-how-en/configuration-of-the-channels)
I'm positive that it will fit on other brand EDF housings, but in case it doesn't I included the 123Design files for you to change the design for your needs
(and please upload it so others can use it, mention my name and include a link to my design :D).
0.2 mm - (propably as rough as you would like)
Print the tube and the wire-fairing upright, gives you the best result.
I printed the thrust tube with Hobbyking PLA at 0.2mm layer resolution and with 100% infill
You should be fine with approx. 15% infill and 0.4 mm walls (looks like it should print just fine with triangular infill) and you should end up with a weight of approx. 40g.
Mounting of the wire-fairing
Mount the thrust tube to your EDF and put the wires through the hole.
Then slip the fairing over the motor wires and glue it into place with a few drops of CA.
trimming of mounting tabs
You might have to trim down the mounting tabs on the sides, so they don't interfere with the ones mounted on your EDF.
Smoothing of the inner surface (not necessary)
You could try to sand down the inner part of the tube to get a bit higher efficiency out of it as the print isn't 100% smooth (I use my thrust tubes straight from the printer and didn't notice any loss of power on my models, but I also didn't make any scientific tests of any kind).