About this 3D model
I still keep sticking my alan wrench into the fan blades by accident. After replacing the fan for a 4th time I decided it was time to make a grill guard. I based this on http://www.thingiverse.com/thing:188358 - I added a couple split pegs to push this into the top un-utilized holes of the fan. This simply pushes on. I added a light-weight piece of kapton tape along the bottom to keep it from vibrating while running (optional). Note when I printed this (because it's only 3 layers thick the center pulled out. I'm not too concerned about the center so I mounted it anyhow.