Trying to replace the adjuster screw on a screen door -- low-profile threaded screw insert and bolt (identification needed)
They are most often called a "binding post", at least that is what the fastener suppliers in the U.S. generally sell them as. I have heard people call them "Chicago nuts" but not often.



As a side note, those adjustable sliding screen doors are difficult to make work properly and of poor quality. Do yourself a favor and get a custom made heavy duty door, with a frame made of extruded aluminum. They are worth the investment over the long haul, provided they are sized correctly and installed and maintained properly. At least that has been my experience.