I noticed that most walls are printed too thick. For example, I printed something today that mostly consists of a 2mm thick wall. I measured it with a caliper afterwards and it was 2.1mm.
That’s a big problem with the following print: Scaleable CD Rack by b0rn3y - Thingiverse. For the back part, the .stl file has the measures for tongue and groove at 9mm and 9.2mm. They are printed at 9.3mm and 8.9mm, respectively. So they are all 0.3 mm off and so won’t fit together anymore.
It is known that 3D printers tend to vary by a few tenths of millimeters, so if the parts you are printing were designed without adequate clearance for printing tolerances then you will have to finish the parts by hand sanding.
Also, double check that the whole walls are that thickness, and not just the top or bottom layer. It’s not uncommon to have one of those two layers squish out more, which can throw off your measurement.
If that’s happening, you can adjust the first layer line width. I generally don’t, and just use a scrapper to clean up the few parts that need the tight tolerance.
