I don't understand why my pieces are not becoming flush.

I don’t understand why my pieces are not becoming flush. Should I be using washers? Alignment is horrible all around.

Screws are too long. You can bias them with washers or use the correct 12mm M5 screw.

For clarification, if you do use washers, they should go between the screw-head and the plastic part, not between the plastic part and the aluminum extrusion.

I think something else is wrong. I took a picture of the wrong screw. I am using M5 x 12mm screw.

That seems like too long of a screw mine barely had enough thread to grab the tnut

Are you sure? You could try 10mm screws, but I would first make sure you’re using the screw you think you are, and that your part is dimensionally accurate.

@Gus_Montoya ​ if you have tightened the screws then they are to long, or from your picture the top one is longer than the bottom, if all the printed parts are of the same dimension then I would think you should be generally fine for alignment once you have them mounted correctly. Having said that I am no expert and I will defer to others with greater experience.

I’ll remeasure them later.

I found the problem, it was the screw (deformed) and when cleaning up the part I carved into it too much. Duh…

That’s what happens when trying to do things in a rush right before work.

Glad to hear that you got it sorted out.