Here's something I can't get my head around due to not having exercised that part of the old grey matter for over half a century. Here's a cross section of the problem. The 'blue bit' needs 0.003" of 'wriggle room/endfloat/free play' within the confines of the 'black bit'. So I need to be able to measure that amount of play at 'A' on the diagram. The question is: where do I stick the shims to achieve this: at B or C or D?
Key: the yellow bit at the top is a nut, The green bit below that is a washer, The purple bit under that is a separate steel tube which forms the inner race of the top bearing. The orange bit is the rollers and shell comprising the outer race of the top bearing, seated against the black coded casting. I've shown the rollers as horizontal for clarity but they're vertical in reality.