With the first one I printed, I had the same screw break problem many others reported. Rather than print just the replacement screw, I tried reprinting at 100% infill. That did the trick!
I also printed an extra screw for the jack with the broken screw (also at 100% infill). It was a little tricky to connect the two parts, but I think it will hold. If not, I'll probably put it back together with some CA glue.