A knob with a ~2cm standoff built in. I made it for the bed leveling screws on my FLSun Cube as they are tucked up behind the bed rails and small and hard to adjust. This uses the small M3 knurled nut which came with the cube.
I am pretty happy with these knobs and find it a lot easier to make fine adjustments to the corners of the bed. The only problem I have is that I like the feel of them and now I have to resist the urge to fiddle with them and mess up the leveling.
Lately I have been playing with G29 V4 and adjusting from there - one turn of the knob/nut is 0.5mm.
I printed it with the larger end down (upside down from the orientation in the STL - sorry) and I used Cura's experimental make overhang printable which slightly beveled inside the knob where the nut goes. This gave me a nice clean face but it is covered by the nut anyway so it doesn't matter much. I used PETG and printed fairly slowly for the grips on the fat end.
Press fit the round nut into the knob, insert a screw and gently tap it in far enough to be able to reach it with a screw from the other end. Then just use the screw and a washer to pull the nut down into the knob and seat it firmly. For me, the nut fit easily and tightened nicely as is but you may have to scale if you find it too loose or too tight.