Bracket to hold a cooling fan (See Thing: http://www.thingiverse.com/thing:1161013 for the fan shroud) and inductive sensor on my Folger 2020 Prusa i3.
OpenSCAD file included but requires the .stl from: http://www.thingiverse.com/thing:1161013
Added new .STL and OpenSCAD files for an 18mm version. One about the same as the original 12mm but pulled in as close to the printhead as I could get it. And a second version I haven't printed yet with the ring pulled back in the Y axis so it will clear my binder clips better the bottom thickened for more strength and tried to make it look cleaner.
If you grabbed the new big-back.scad file before I'm putting this notice up - it probably won't work. I had to add a bit more clearance between the loop and the extruder. I've uploaded the replacement file and the print of it is what's shown installed in green.
I printed this in PETG since I like it better than ABS, but ABS should be fine as well. I wouldn't suggest PLA since this mounts right against the cold break and heatsink of the extruder, but the designer of the bracket I based this on said he used a PLA version successfully.
Original inductive bracket suggested printing with 100% infill, but the fan bracket I based this off is more substantial than the inductive bracket so I just went with 30% and it seems plenty strong.
I've printed and used both the 12mm and 18mm versions in PETG and ABS. Even when my printer was having overhang/bridging issues I was able to print this with no supports.
I made this in OpenSCAD by importing the bracket from Thing: http://www.thingiverse.com/thing:1161013
The loop for the inductive sensor I added manually based on measurements from Thing: http://www.thingiverse.com/thing:671600 with a small stretched cube to attach it.
I expected the fan bracket part to need support, but when I sliced it slic3r with supports enabled it didn't add any - it did however add some to the right mounting block so I went back in and added a cube under that so it could print without any support.