I had an old machinist ruler that actually did have 64ths - barely could read it haha - time to get out the calipers! One reason these whole even numbers are u

I had an old machinist ruler that actually did have 64ths - barely could read it haha - time to get out the calipers! One reason these whole even numbers are used is because it's easier to inspect with basic tools - ie just fold/layer it a few times and measure the thickness - like using a rule to measure 64 sheets of 1/64" stock and hoping to get 1". The evenness is about doubling/dividing to achieve this effect. They also had very primitive measures for bore size that worked the same - ie "gauge" for shotguns was the number of how many balls of the barrel's size added up to 1 pound of lead, so you could have a basic scale and infer everything from there.