ET: Engine (Twin) Identifying cams

[kettlrj]

I take your point but I think I could design a spindle with a shoulder that would screw up tight leaving the holes pointing downwards 45 degrees left or right?

Sorry Jim, but a shoulder will not guarantee where the hole ends up. It’s to do with where the threads in hole and the one on the spindle start relative to each other, which normally can’t be controlled.
Richard Kettle