ISO Drawing unit

[rumlyronny]

A question arised in my group..
Where is it stated that the units in an ISO drawing are "mm"? In which standard?

I'll be very happy to find this info


-RR

 

[CheckerHater]

ISO 129-1

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

 

[rumlyronny]

Can't find that "mm" is mentioned, but if you mean chapter 4.1 - last section?

"Where all linear dimensions are expressed in the same unit, the unit symbol may be omitted, provided the
drawing or associated documentation carries a statement of the unit used."

By this I read that it should be stated in the drawing that all dimensions are in "mm". No standard is telling the default unit for an ISO drawing.
Agree?

-RR

 

[CheckerHater]

I mean Chapter 4.3 Units of dimensions referencing SI units.

Which year is your version of 129-1?

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

 

[rumlyronny]

Ok, but still chapter 4.3 only state SI units, not "mm" in specific.
I know that the relevant basic SI unit is "m", but with the allowable prefix(es) there can be "cm", "km" and "mm"

My version of 129-1 is from 2004. I see that it is foreseen a new version this year.

-RR

 

[drawoh]

rumlyronny,

I have a copy of ISO[ ]406 Technical Drawings -- Tolerancing of linear and angular dimensions. Under Units, it states that "Deviations shall be expressed in the same unit as the basic size." As per ISO[ ]406, you can dimension in furlongs if you want, but you have to express tolerances in them too. I assume you need a note on your drawing indicating what the dimension units are.



--
JHG

 

[rumlyronny]

Thank you for your time
I'm quiet happy

-RR

 

[CheckerHater]

So am I.
ISO 406 is happily discontinued. Perhaps for mentioning furlongs
There is a small hope that ISO 129-2 could shed some light on the issue, but unfortunately it still in Draft stage since 2013

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