Number one son reckoned I should have a go at printing the screw jack above, so I did. The intriguing thing about this design is that the entire object is printed as one, standing on its edge. There are some fairly prodigious unsupported elements in the design (you can see how the bar at the bottom left of the picture has some bowing at the bottom as it sagged during print) but to my amazement it printed mostly OK.
The only major problem was that I broke the knob off the screw thread in the middle when I was trying to "un-stick" it from the elements around it. However, the designers have thought of this and provided the design file for just this component so you can re-print it.
The jack does work; you can raise and lower it using the screw. I've not got a use for the jack as such (although it makes a fine support for the robot printing arm when I'm not using that). If you've got a few hours to spare and fancy a challenge I'd advise you to have a go. Great fun and amazing to think that such a complicated device was made as one thing.