What is considered acceptable wear for the pitman arm ball? I have an original pitman arm off my 1910 T (marked T929)and I'd really like to use it if I can. It is worn, measuring .978 at the sides of the ball and .986 at the front of the ball. If this isn't acceptable, can the ball be welded up and machined to spec?
If the steering can be moved throughout it's range without binding, and there is no appreciable steering slack when going straight ahead, I can't see why what you have isn't going to be fine. I am assuming that you do NOT want to use an APCO drag link cap.
If you want, I don't see why you couldn't build up with weld and file back. Drill a hole in a stub of material and use that as a spherical gauge and work slowly with the file or hand-held air sander. It will go faster than you think.