One of the project I worked required us to use specific captive bolts. The shoulder length, tread size, knob type, etc. all had to be a specific value. I researched companies for a while until I found one. That produced exactly the screw I wanted. Along with the procurement team we contacted them and were able to get a few samples, which were used in prototypes of the product we were developing. It was difficult to communicate with them since they were based in another country, but the samples we received met our specifications and strength conditions. So we ordered more screws from them, for production use. After our first order, which were fine, we ordered more for a second patch and they then explained they wouldn’t produce the screws anymore out of nowhere. I guess they weren’t profitable or no one really bought them. So now I was back to step one looking for another vendor with incomplete orders waiting. Lesson learned to make sure you have a backup plan or alternative source.