Replicator 2 - 40 mm - tool stopping fan guard

As seems to be a common problem, I've nicked my fan with tools before. The stock fan guard also always seemed off to me. Always falling off during maintenance and not having anything holding the top in.

I've taken ideas from a few sources. I wanted a retaining pin for the top connector. I also wanted it to stop tools. While I was designing it I also noticed there was space all around the fan so I decided to extend a shell around the fan to make the fit even more snug.