Flatness tolerance callout I have never come across 1

[rkmistry]

I have come about a flatness tol. never seen before. I use 1994 version, may be its in 2009. If someone can help me with this. Here is how the flatness is called out on the same surface:

The first feature control fame: "flatness symbol|0.25"
second feature control directly below it (same leader line): "flatness symbol|0.1/50"

I would really appreciate if someone can tell me what the second feature control frame means.

Ray

 

[CheckerHater]

This looks like flatness applied “on unit basis”, but something is missing.
There should be square or diameter symbol before the number 50, meaning flatness 0.1 per every 50 x 50 square (or 50 dia circle)

 

[CheckerHater]

Or it's not flatness, but rather straightness (same principle)

 

[CheckerHater]

Or it should say "50 x 50"

 

[powerhound]

If you look on page 162 of the 94 standard there is an example of how to specify it. The explanation is on the previous page, para. 6.4.2.1.1.

Powerhound, GDTP S-0731
Engineering Technician
Inventor 2010
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[rkmistry]

@powerhound, I don't have access to 94 manual, can you please elaborate your reply.

Thanks

 

[CheckerHater]

This is the basic idea:

 

[powerhound]

CH has it exactly.

Powerhound, GDTP S-0731
Engineering Technician
Inventor 2010
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[rkmistry]

Thanks CH. Makes sense. I will have to check with the customer and see if it is a typo on their drawing.