So posted this topic earlier, and had to figure out the file thing. So just would like some thoughts on how to make the center "shaker section" easier to print? The rest I think will print ok but not sure if the threads will match, and the threads aren't printing that great.
I have been looking at this thread for some time ... must be the most important salt shaker in the world of 3d printing :) no offense here!
first thing that make impression is the thread itself, very narrow grooves very deep, look at the cross section, this will not print well and even if it prints it will break or chip off very easily. try to make the thread more wide and less deep, with bigger thread angle, i.e more than 60 deg.
second you can see the cavity in the middle where the protrusions are, those things are not printed well. you should make it solid in this section.
in case that you still struggle with the thread you can simply remove it, use snap fit parts and in case they don't snap fit use magnets to keep them in place.
the easiest way to avoid supports is to cut the parts so that you print flat bottomed parts. then you need to glue the parts together or to find some way to fit them to each other. designs for 3d print are not like designs for machining, fdm 3d printed parts are easy to brake or chip out and overhangs need to be supported, on lathe the fabrication process is entirely different therefore threads are easy and good on lathe and always compromised on 3d fdm prints.
For the threads try to configure an angle of 60° this is easier to print. Otherwise you could model it to a trapezoidal thread with 60° or even 90° angle. It will be much more stable and way better for printing.
Also, so that the thread will move smoothly do not hesitate to design the counter parts more loose. I would say at least 0.5mm difference as tolerance between bolt and nut.
For the middle part, I would further suggest to give it a chamfer on the side you want to place it onto your bed again with 45° angle so you do not need supports here.
I hope some of my suggestions helps you!