Machining of round tensile samples to ASTM A370

[LEB1]

Hi all
When machining Round tensiles to ASTM A370 Fig 5 specimen 4 is the metric 12.5mm size a standalone size and NOT a conversion from the imperial 0.500" quoted.
what is the reason for this not being 12.70mm ?

L.E.B1

 

[mrfailure]

The answer is proportions. There is a 1.6% difference between the English and metric diameters for these specimens. This is the same percentage difference between the 50.8 mm gage length of a 2" specimen and the 50 mm metric length that is actually specified. The difference is to maintain specimen proportions while maintaining easily defined dimensions.

Aaron Tanzer

http://www.lehightesting.com

 

[metengr]

Simply put, Codes and Standards typically rely on soft conversions between SI and US customary units.

 

[Zinov]

Hi Leb1,
I think that in all ASTM standards there is a sort of 'warning' in the 1st section of the standard. This 'warning' concerns units conversion between imperial and metric

Regards,