# Did You Know?



## astjp2 (Apr 21, 2015)

The inch changed by 2 millionths of an inch in 1959? This was to make it exactly 25.4 mm per inch.....so if you have a real accurate indicator, built before 1959, it will be off!  Just some trivia.  Tim


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## John Hasler (Apr 21, 2015)

astjp2 said:


> The inch changed by 2 millionths of an inch in 1959? This was to make it exactly 25.4 mm per inch.....so if you have a real accurate indicator, built before 1959, it will be off!  Just some trivia.  Tim


And so, of course, did the mile.  That can be a headache for surveyors in some circumstances.  Thus we have the "statute mile" and the "survey mile".


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## Tony Wells (Apr 21, 2015)

Yes 

And the UK inch changed to, but a different amount.


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## 18w (Apr 21, 2015)

I knew something was up, and all this time I was blaming my Chinese gage blocks!   

Darrell


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## ariscats (Apr 22, 2015)

Go metric because the nose of the King might go a little bit longer like Pinocchio. L.O.L.


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## astjp2 (Apr 22, 2015)

Could the Chinese make gauge blocks before 1959?


18w said:


> I knew something was up, and all this time I was blaming my Chinese gage blocks!
> 
> Darrell


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## ARKnack (Apr 22, 2015)

astjp2 said:


> The inch changed by 2 millionths of an inch in 1959? This was to make it exactly 25.4 mm per inch.....so if you have a real accurate indicator, built before 1959, it will be off!  Just some trivia.  Tim



Wow. that's about 1/8" per mile. I hope they calibrated my speedometer correctly.


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## 18w (Apr 22, 2015)

astjp2 said:


> Could the Chinese make gauge blocks before 1959?




Dunno but I have a couple of indicators that were.


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