[Eliot Ness]

I read these post, and I am having a hard time understanding what they are trying to do with piece of tubing and enlarging the hole etc.......

Mark, they are talking about the hole where the tuning shaft goes (circled in red).  It becomes worn (enlarged) so they either enlarge it and install a brass bushing, or using tubing to do the same.  I copied Ron's picture and circled the area in question in red.  Hopefully this will help clear it up.