[hharney]

I would suspect fitting issues cause the internal abnormal wear. There may be some justification to prop balancing also but the higher percentage of damage is most likely the spinner not properly fitted. More washers would be one concern but I thought I read somewhere that the number of washers is limited. This would indicate that the spinner or the internal support is worn beyond specs. I have seen many units with multiple washers, homemade too. One needs to be careful as the internal support will be compromised on the prop hub if too many washers are stacked up. Remember these things are 50+ years old and have been removed at least 50+ times.