Hello, I'm in the planning stages of a personal project that involves creating a cellphone mount. Its going to end up being made up of a number of different pieces, and while I have a small history of 3d modeling, I have never designed anything with the purpose of it being made in real life, and this will be my first foray into 3d printing. First question, screws. Is it a good idea to make 3d-printed screws? Can the threads be represented accurately, can they survive small amounts of trauma? It seems like this would be the easiest way to solve some of the design challenges I'm coming across, as I could simply make a screw and screw hole match each other perfectly. If printed screws are not advisable, what about making unthreaded holes with the purpose of driving a metal screw into them? Should the hole match the shaft of the screw, or should it be somewhere between the shaft and the apex of the thread? Alternately, are there any commonly-used designs for fastening pieces together? What about hinges? I was thinking about simply having the pin with a cap on one end and a threaded tip in the other, to allow for a sort of screw-on cap. If threaded objects are not advisable, though, I really don't know what I would do for the hinge. Also related, what should I expect when designing two pieces that are meant to play on each other? In the case of a hinge, can I make a pin with a diameter of 3mm, and a hinge with a hole of 3mm and expect them to fit perfectly? Stiff? Snug? Not fit at all? Does it depend on the material? Thanks for your time!