Flatness Callout Question

[rsm7400]

Good afternoon all. I have a new print with a callout I am unfamiliar with. It is a rectangular plate with the following callout tied to the thickness

I am unfamiliar with the TOT. All I can think of is Total Over Thickness? Not really sure.



________________________________
Ryan M
Quality Engineer
3d Printer Hobbyist

 

[Nescius]

TOTAL? Check out the link below:

http://www.tec-ease.com/gdt-tips-view.php?q=90

The brief Tec-Ease article is...brief. It does, however, specifically say that "In the early days of GD&T, TOT was used to indicate total."

 

[CheckerHater]

Yes, indeed, TOT was used to indicate "total" but only to separate circular and total runout.

I am wandering if by any chance drawing is produced somewhere overseas, and what standard it follows exactly?

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[rsm7400]

The customer is an American based company, but that doesn't mean their customer is not. We resolved just to flat grind the part to with in .002, which will be easy. Thanks for the inputs though!

________________________________
Ryan M
Quality Engineer
3d Printer Hobbyist

 

[CheckerHater]

I may be late for this discussion, but is there a way to directly ask the customer what they think it means?

I understood you have solved your problem, but tomorrow yourself or someone else may encounter similar "creativity"

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[monkeydog]

According to ASME Y14.38, page 121, TOT is an abbreviation for total.

 

[CheckerHater]

Thank you monkeydog,

The only thing left now is to find reference to "total flatness" in ASME Y14.5

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[monkeydog]

I have ASME Y14.5 1982

Appendix D (Former Practices) paragraph D6 reads:

D6 Identification of the Tolerance Zone
For a positional tolerance or symmetry tolerance, the word TOTAL following the tolerance value was used to represent the distance between two parallel planes (noncylindrical zone). For the present practice, see 3.6. For a positional tolerance, the symbol R following the tolerance value was used to represent the radius of a cylindrical zone or one-half of the distance between two parallel planes (noncylindrical zone). The radius method is no longer used.

 

[CheckerHater]

Thank you md,

So, it was "former practice" back in 1982 (still not applied to flatness)

Sometimes symbolics come back, like BAS for basic in 2009, but still no sign of total flatness. Pithy

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[monkeydog]

Not saying it's right, but I would bet a red star, that was the intent of the designer.

 

[rsm7400]

Thanks for still looking further in your standards. If the project moves beyond this prototype run I will ask what their intent of that call out is. Because of the size of this ceramic component, it does not fire super flat. We have intentionally left stock on the thickness to diamond grind both of the main surface to final thickness. Because of this planned process, we will easily hit the flatness of .002"

________________________________
Ryan M
Quality Engineer
3d Printer Hobbyist