Quote Originally Posted by benjiboy View Post
How do you re-collimate the lenses when you re-assemble them to ensure that the elements are centred to a datum line, and are parallel to each other ?

I don't. What do you suppose I do when faced with a lens that's pretty old and not worth enough to spend money on professional repair? Well, in those cases, I carefully take it apart, do what I can, and carefully put it together the way they came apart. It works well enough and for the purpose intended, it's fine. If I mess up, oh well...

Obviously, I don't do this for my high-dollar Nikkors or anything else that matters.