The more i use the gray material the more I am amazed with i and like it. It cuts and sand easily, and can be tapped for small items. If the part is large enough it is good to 200 degrees. Ask me how I know!
This is the first time I have tried it as a wear part. I wanted to try and make U joints for my trains. I have about 10 minutes of run time so far. It all seems to be OK, The wear areas are liberally oiled.
I hope I don’t have to find out what the life span is and repair with new U joints.
Bill