The original adjustable legs from the IKEA Fullen were too high for my situation, so I remodeled them in a shorter version but kept the adjustable height features.

They can be adjusted from 85mm to 105mm. The threads at the top and the bottom are the same as in the original (Top: M8x1.25|Bottom: M22x2.5). So if wanted the top screw and the adjustable feet from the original can be reused. I reused the top screw because a 3d-printed M8 screw would be too weak and printed the bottom feet instead of using the original one because I wanted to legs to be uniformly white.

I printed my legs without any supports; make sure to disable them so they don't interfere with the inside thread. Depending on your setup, a brim is needed for better adhesion.

IMPORTANT: The threads are designed with an additional 0.1mm margin so that they work smoothly. I've printed my legs with an adaptive/variable layer height, pending between 0.08 in the areas of the threads and 0.28 in the middle for faster printing time.