"E" With Metric Tolerance 2

[drbauer]

I am looking for an explanation of the use of the letter E in a circle following a metric tolerance (h6) on a German drawing

 

[ewh]

Revision?

 

[Heckler]

In the Military/Defense world we put this symbol on our drawings to indicate what the changes were on each revision.

Here is an example of a Milspec bolt

http://www.mooload.com/new/file.php?file=/data/210607/1182437217/MS9560G-X+-+Double+Hex+Bolt.pdf

Heckler
Sr. Mechanical Engineer
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(In reference to David Beckham) "He can't kick with his left foot, he can't tackle, he can't head the ball and he doesn't score many goals. Apart from that, he's all right." -- George Best

 

[drbauer]

It does not appear to be a rev

 

[PaulJackson]

drbauer

Circle(E) in ISO signifies the "Envelope Principle" which suspends the ISO "independency principle" for measurement of size and form and invokes conditions equivalent to the ASME "Taylor Principle, Rule #1" commonly known as "Perfect form @ MMC".

Paul