Once upon a time most manufactured stuff was assembled with screws with nuts or inserted into machine tapped holes. Now, almost everything has various forms of self-tapping, thread-forming or other type of screws going into plain holes. After taking something like that apart for repair (something the manufacturer often never intended), the challenge is to re-assemble the item so as to be usable again. A common misstep is to blindly start putting the screws back while absently remarking how difficult it seems. That is because you are probably cutting new threads which can easily strip as you try to tighten. Over the years I have developed a simple technique. Before starting to tighten, I turn to the left while putting a bit of pressure on the screw until I can feel it drop slightly often with an audible "click". That is the sign that the screw has found the original threads. It should go in easily and be able to be tightened as new.