This is a replacement part for a mirror sliding closet door in my house.
The upper track guide that is attached to the door broke a long time ago. The missing guide would cause the door to jam on the track if you used anything but light tension while closing the door.
The closet door is the original from 1980, so finding a replacement part was impossible. The original plastic piece was riveted to a metal bracket giving me no easy way to make an exact copy. I realized that the metal side frames of the closet door were hollow and that I could redesign the guide to slide into the frame.
After a couple of tries, I came up with this final design that works perfect.
I doubt anyone will ever use this, but I'm uploading just in case.