ISO Tolerances

[QA4]

Hi,

I got a print that has the following tolerances listed and i am having trouble finding what the actual +/- tolerances are? It's all metric.

ISO 2768-mk
ISO 13920-BF
ISO 1101

Example of one is: Dia 41H8(2X)

Thanks!

 

[IRstuff]

ISO 2768 has a table with the tolerances; it's only 7 pages long, so what's the difficulty?

TTFN

FAQ731-376

 

[QA4]

I should be a bit more specific. I can't seem to find what ISO 2768-mk tolerances are? In the example i do not know what the "H8" means?

 

[IRstuff]

Perhaps you have a typo. 2768-m certainly exists.


TTFN

FAQ731-376

 

[drawoh]

QA4,

This might be a better question for the Drafting Standards, GD&T & Tolerance Analysis forum.

Your Machinery's Handbook has enough information to make sense out of ISO tolerances. Your hole, Ø41H8(2X) translates to Ø41.039/41, and there are two features to be fabricated this way.

The H8 tolerance is recommended as part of a clearance fit, to be mated with an f7 toleranced shaft. Under ANSI B4.1-1967, this is classified as an RC4 fit. The H8 tolerance is called on some of the other ANSI fits.

JHG

 

[KENAT]

Iso 2768 is a 2 part document giving tolerances for essentially machined & sheet metal parts. First part gives different tolerances for linear & angular dimensions based on size and tolerance class. Part 2 gives geometrical tolerances, again based on size and class.

'm' (Medium) relates to the class for part 1, 'k' relates to the class for part 2.

You will have to get a copy of the standard, you can find portions of part 1 free on the net, possibly under DIN 2768, but you'll have trouble finding the whole thing for free, and arguably shouldn't expect to.

It's a bit of a Dog from the standard US/UK practice point of view but the Germans use it so it must be good right?

ISO 13920 I believe does similar for welded parts but I'm not sure.

ISO 1101 is a geometric tolerances spec, perhaps comparable to part of what 14.5 covers in the US.

H8 is to do with 'standard' shaft/hole fits as drawoh says, ISO 286 should explain this, again portions are available on the net.

Posting guidelines faq731-376

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

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

 

[rb1957]

"the Germans use it so it must be good" ...

jawohl ! (click)

 

[IRstuff]

Need to add a title to the response, like, "

Jawohl, Reichsmarshall!" (click)

Otherwise, it just doesn't seem to have the same impact, at least, to me...

TTFN

FAQ731-376

 

[Dan320]

No one who can speak German can be all bad...
From the Simpsons show.