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by nickpinkston 1211 days ago
Yea, I'm always blown away by the old master machinists I've worked with when they talk about getting to "50 millionths" (ie half a tenth of a thou) on manual lathe and measurable with a bench micrometer [1].

Also the auto body guys whose hands are like profilometers [2] and can just feel various surface quality [3]. This is actually where precision originally came from with the 3 plate lap where you're just using fingers and candle soot to create crazy high surface flatness [4].

[1] https://willrich.com/product/starrett-direct-reading-bench-m...

[2] https://en.wikipedia.org/wiki/Profilometer

[3] https://en.wikipedia.org/wiki/Surface_roughness

[4] https://ericweinhoffer.com/blog/2017/7/30/the-whitworth-thre...

1 comments

You should watch the documentary on the most famous Card Mechanic (Card Magician, but they like to go by 'mechanic') - Richard Turner.

He fan feel thousands of inches and can note the individual thickness of each card he touches.

He is also 100% blind, and he talks about how sensitive his touch is.

He is unbelievably remarkable

https://en.wikipedia.org/wiki/Richard_Turner_(magician)

the documentary he is in is called "Dealt"

https://www.imdb.com/title/tt3127902/

Very cool - thank you!