The one I made in the original thread that I linked held up fine, but I kept having problems that I later discovered was because the gate was sitting right in front of the opto beam and causing intermittent breaks in the beam. I made several out of brass (because it was much easier to work with) until I got to one I was really happy with. I then lucked into an original and have had that on my game since.
It is a delicate balance of getting the gate to sit low enough to not interfere with the playfield, but still open enough for the ball to pass under due to the very small amount of movement provided by the solenoid, and the proper height to stay out of the opto beam.
For my final brass gate, which I was happy with, I actually made the gate itself W shaped in the middle so that the ball had more room to pass under and also keep it out of the way of the opto. That worked really well and provided a ton more room for error.
Edit: The brass, being easier to work, was also easier for the ball to malform during play. It wasn't a big problem, but it did need to be straightened a little every once in a while.
Post edited by aobrien5: 5th edit? need to proof read more.