So the stock rubber feet for the MK3 leaves your printer wobbling all over the place, the hard feet are great but make your printer a lot noisier. How about something in-between?
This is a designed to hold the stock rubber feet in place while stabilising them as much as possible. I have achieved this by designing the foot holder so that only a very small proportion of the foot clears the bottom of the support. The other part to this is that the foot holder is slightly undersized so it compressed the feet slightly to aid in stabilising the rubber feet.
Important: when you first fit the rubber feet the holder will seem too small, that is how it has been designed, as you tighten them against the frame it should force the rubber foot further into the part and into the correct position with just a small amount of the rubber foot clear at the bottom.
I then secured them using a 3D printed 3030 T nut for M3 fasteners (This is the one that i used. https://www.thingiverse.com/thing:3199057)
These have significantly reduced the amount my machine wobbles round and has a positive effect on print quality while maintaining it's quiet printing.
Update: I have slightly Tweaked the file to allow extra tolerance as i was finding installing them was slightly hard.