Test printed but not yet flown
I designed this for mounting 2204 motors on 1/2" wooden booms. It is customizable not overly so right now. The mounting hole pattern and boom size are configurable but the shell doesn't fully adapt to all possible changes yet.
You may want to enlarge the screw size slightly, my printer is very accurate and I still had to make them slightly larger for 3mm bolts to fit easily. With the stock 16x19 mounting pattern the screws will just penetrate the sides of the wooden boom. The bolt shafts are 20mm long so 22mm bolts are probably the best bet I don't have a spare motor handy right now and didn't want to fully strip an existing quad to test. I did take one motor off test mounted with some 25mm bolts...they were too long so I couldn't tighten them but the bolt pattern fit..
I printed with a 0.4mm nozzle at 0.48mm line width and 0.24mm layer height using 4 perimeters for strength. I only used 30% infill and may try even less since I want to keep these light and the high perimeter count should give it enough strength. But we'll see how they do in some crashes soon.
The bridging wasn't perfect in PLA or PETG so I ran a drill bit through to open the holes a little and clear any stray filament. I also used tweezers to remove any sagging threads. 1/2" dowel fit perfect and bolts went right in.
I started out modifying this design: http://www.thingiverse.com/thing:1025343 adapting it to fit a 1/2" dowel. I was able to make the modifications but the resulting part was too weak and I decided starting from scratch would be easier than trying to make the changes I had in mind.
I tried to keep it parameterized from the start but got sloppy in a few places and haven't gone back to tweak them yet. This is my first attempt at designing something to work with the customizer and this seemed like a simple but complex enough part to be a good first go.