I keep losing my outdoor faucet handles. Although they are easy enough to buy, I never seem to be able to find one when I need one. A simple fix is to just print a bunch at once and leave them in the faucets.
There are quite a few faucet handles available for printing already, but I wanted one that was small, good looking and could be printed in PLA. The others mostly look like copies of commercially available keys. These requires printing in ABS, since they are to thin to take any force at all if you print them using PLA.
The common type of keys for outdoor faucets where I live (Sweden) seem to be called 8mm, but the square taps in the faucets are actually a bit smaller (7.5mm). I don´t know whats up with that, I just made the handle to fit my faucets.
You want the handle to be dense and snug since it should stay in place and be handle to handle a bit of force. I printed mine on 0.2 mm layer height and 75% infill. As usual you might have to adjust the scaling slightly to produce a snug fit. But the handle prints with perfect dimensions on my particular printer, which I have tried to calibrate as precisely as I can.