The designer of the part didn't review the tolerance of the thread when he designed the part and put the tolerance he needed on the assembly and put the problem on manufacturing's back. A solution would be to have a turned diameter on the shaft and a counterbore on the impellor to locate the part and using the thread to retain the part.
I'm sure the answer will be we've been doing it this way for years. Have they ever inspected the assembly before this to make sure of the runout? I bet they haven't. |