This is only the nut, the part under the frame where inside is present a nut 30mm lenght and 6mm large (i think is a M6).
need to printed 30 mm up the bed, with support BUT NOT with support inside the enter part where the nut need space. With cura and simplify3d is possible, with other slicer i don't know.
The frame is from: https://www.thingiverse.com/thing:3167714
The tripod is from: https://www.thingiverse.com/thing:2250451
i wrote this as a remix but not really true, the above part (frame and tripod) are the same... the nut is mine from scratch
Anycubic Kossel linear plus
print with object 30mm up the bed, with support BUT NOT with suppor in the inside part (where the nut need space).