ISO 2768 Postion Tolerance Question

[jckc779]

Simple question, does the "Ranges in nominal lengths in mm" for position refer the feature size, for instance, hole diameter, or does it refer to the distance between features?

 

[KENAT]

jckc779 - which section of the standard are you asking about, part 1 or part 2? I assume part one.

My understanding is that the tolerances apply to any linear dimension not otherwise specified per 4.1 of my 1981 version of the std (part 1).

So depending on tolerance scheme they potentially apply to both the locating dimensions and the feature size dimensions.

Obviously depending on the value for the size and location dimensions the actual tolerance may be different.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[pmarc]

Excerpt from ISO 2768-1:1989.
"This part of ISO 2768 only applies for the following dimensions which do not have an individual tolerance indication:
a) linear dimensions (e.g. external sizes, internal sizes, step sizes, diameters, radii, distances, external radii and chamfer heights for broken edges);[...]"

However the standard has no power over theoretically exact dimensions (in ASME Y14.5 they are called basic).

 

[CheckerHater]

Also from ISO 2768-2 Geometrical tolerances for features without individual tolerance indications:
"General geometrical tolerances apply to all geometrical tolerance characteristics, excluding cylindricity, profile of any line, profile of any surface, angularity, coaxiality, positional tolerances and total run-out."
So, no position. (you were asking about ISO 2768 position, right?

 

[jckc779]

I need to clarify my question. I'm looking at a drawing that has the statement "TOLERANCES ARE PER: DIN ISO 2678-FK". As I understand it, the F refers to Class f (fine) linear and angular dimensions and the K refers to form, such as position, flatness, perpendicularity, etc. These form tolerances have specified values for ranges of size, ie "up to 10mm", "10 - 30mm" etc. So, if I have a plate with 7mm holes located 1300mm apart from each other, is the tolerance range the feature size (7 mm) or the distance between features (1300mm). Or am I missing something?

 

[pmarc]

jckc779,
1. The drawing statement should be: "TOLERANCES ARE PER: DIN ISO 2678-fK".
2. K refers to general geometric tolerances, but position is not amongst them, as CheckerHater noted.
3. For the 7mm holes general linear tolerance class "f" applies. According to the Table 1 in ISO 2786-1 this will be +/-0.1. For 1300mm distance between them the same general linear tolerance class "f" applies. According to the Table 1 in ISO 2786-1 this will be +/-0.5.

 

[KENAT]

The location tolerance comes from the tol on 1300mm.

The hole size tolerance comes from the tol on 7mm.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[jckc779]

Thanks for the help!