[HO455]

I was rereading your thread the other day and later it occurred to me you had been talking about milling several index holes to find the ideal distance. With your access to an alignment rack you could grind down the rivet in the saddle that indexes the shaft. After reassembling without an index, move the shaft around and find the best location to balance your alignment and the shim stack. Obviously you couldn't drive it that way but as a test bed it should work. When you are satisfied mark and mill your new index holes. Then it would just be a case of drill out and replace the rivets with more positive indexing cap screws

I drilled my rivets out after I found one side half sheared off and no way to positively position the shaft. When I looked at the other side I found that there was approximately an 1/8" of play between the rivet and the index hole. By machining the new hole to 3/4" and using a 1/2" cap screw I now have virtually no play. I did have to shorten the head of the cap screw as my index holes were not deep enough. Anyway its just a thought.