George, to lap tools that fit tight I apply the 400 grit silicon carbide lapping past to both parts and just work the parts together until I have the clearance I need. I renew the lapping compound every few minutes. I do not think that I am removing very much, maybe in the ten thousandths. It does take time. I cannot figure out why Carl hardens the wheel cups so hard. I just do not think at this time in history any of these tools are going to be used so much that they will wear out. In my experience wheels press on fairly easy. If they do not there is a risk of bending the axle. I find I usually have to ream the wheel bore to get an interference of about 0.002”. That is interference between the bore and shaft ignoring the serrations.
Most of my tool interference problems have been on the lower tool holder where I think less hardening has occurred. The rivet sets have always seem to fit well in the top tool holders. Most of the rivet sets I use are either original Lionel or from Jeff Kane.
