my tool of choice for checking alignment was a 6'' slide rule and a feeler gauge. Then when digital came along I had to use a Dial Indicator because noone knew what a slide rule was.
slide rule museum
actually scatter I have to wonder if you know what a slide rule is. I have a Picket N4-ES in my desk and while it is great for dividing, multiplying, and finding square roots I have no clue as how you would change the alignment of 2 holes bored in a piece of cast metal with it
but then you guys that claim you can align holes bored in a piece of cast metal are some magical fellas in my opinion