which DIN/ISO std to reference for a "STD" tolerance on a drawing 1

[Reman101]

All,

We are kinda new to this DIN/ISO thing here and we have a drawing for a customer in Germany and we need to reference a tolerance we were given but which DIN/ISO tolerance do I put on the drawing? I found two so far, DIN-7168 (appears to be an older std) and DIN/ISO-2768 (appears to be newer). For now I am going to reference the 2768 std, but is there another one I should use or is this "the one"?

Thanks,

Reman

 

[pmarc]

What are those general tolerances on your print for? Is it trully customer requirement to have a reference to ISO/DIN standard or is it just your idea in order to have the print looking more European? What kind of part is the print showing - is it machined element, sheet metal, casted/forged/molded product or something else? Sorry if this questions sound stupid, but I'd simply like to know it.

 

[KENAT]

Like pmarc says, before just deciding to invoke make sure the standard applies to your application and that you understand the implications of the standard and understand how to use it.

ISO 2768 has some elements that are a bit different from the typical US way of doing things so make sure you, and if you use them any external machine shops etc., understand it.

A quick Google search suggests 7168 is not to be used for new designs.

Posting guidelines faq731-376

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

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

 

[juergenwt]

ISO 2768-1
Tolerances for linear and angular dimensions without individual tolerance indications.

ISO 2768-2
Geometrical tolerances for features without individual
tolerance indications.

http://www.ams-prototipi.it/webfiles/iso.pdf

http://www.unionpart.com/download/ISO 2768-2.pdf

Those two should be sufficient. It clearly states: "without individual tolerance indications".

 

[pmarc]

juergenwt,
You should have mentioned that both parts of ISO 2768 are intended for: "[...] dimensions of parts that are produced by metal removal or parts that are formed from sheet metal" with a remark that they "[...] may be suitable for use with materials other than metal" and for "[...] features manufactured by other processes" with special examination required. This is very important detail which is unfortunately quite often forgotten.

If OP deals with parts other than falling under this requirements... well, a lot can happen. Hence my initial questions.

 

[juergenwt]

Thank you pmark.

 

[Reman101]

Thanks guys. This item is a re-manufactured cylinder head and we are mimicking their tolerances on the original OEM drawing. There is just one dimension in question that doesn't have a specific tolerance so we were going to reference this std. to cover ourselves. This is a metal part and it is removed from certain areas during manufacture, this particular dimension is where the valve guide is pressed into the head (how much is sticking out). Would that count?

 

[juergenwt]

Reman 101 - ISO 2768-1