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Does the ISO drafting standards actually say not to use trailing (insignificant) zeros on dimensions 2

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fcsuper

fcsuper

Mechanical
Apr 20, 2006
2,204
Does the ISO drafting standards actually say not to use trailing (insignificant) zeros on dimensions? If so, where?

This is easy to find in ASME Y14.5-2009, but I cannot seem to find it in the ISO standards, like 129.

Matt Lorono, CSWP
Product Definition Specialist, DS SolidWorks Corp
Personal sites:
Lorono's SolidWorks Resources & SolidWorks Legion
 
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Would this be sufficient:

Decimal rule, ISO 14 659

"After the last indicated digits of dimensions and tolerances, zero applies (no rounding)."

Looks like "last indicated digit" is not zero, hence zero is not indicated?

Same in ISO 8015-2011:

"5.6 Decimal principle
Non-indicated decimals of nominal values and tolerance values are zeros. This principle applies to drawings
as well as GPS standards.
EXAMPLE 1 ± 0,2 is the same as ± 0,200 000 ...
EXAMPLE 2 10 is the same as 10,000 000 ..."
 
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Matt,
I do not think there is such rule in ISO. If you have a possibility take a look to latest revision of ISO 14405-1:2010 "Linear sizes". There seems to be quite a mess in the area you are asking for (see attached picture from that standard [figs. 9-11]
 
 http://files.engineering.com/getfile.aspx?folder=7bdecb12-1ff7-4f1a-9c16-14a9b03f50e0&file=iso14405-1_2010.JPG
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pmarc,

This isn’t a “mess”, but rather an EXCEPTION – Uniformity of inscription on drawings with limit dimensions, absolutely no different from ASME Y14.5 Para. 2.3.1 b) and c)
 
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CH,
Really? So why on the very bottom 2 pictures all limits have trailing zeros on third place after decimal comma? Are they really needed? Wouldn't two decimal places for each of those 4 limits be enough? Does ASME legitimate such practice as shown on those 2 pictures, and if so, could you indicate where?

I absolutely agree that all limits should have the same number of decimals, but why 3 and not 2?
 
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Of all the standards for me to be missing, I have 14405-2, but not 14405-1. Arg. Anyway, would you happen to have the verbage in 14405-2. The statement is 8015 isn't enough to preclude the use of insignificant zeros.

Matt Lorono, CSWP
Product Definition Specialist, DS SolidWorks Corp
Personal sites:
Lorono's SolidWorks Resources & SolidWorks Legion
 
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pmarc said:
I absolutely agree that all limits should have the same number of decimals, but why 3 and not 2?
Click to expand...

I have no idea.

It may have something to do with tolerances per ISO 286 being specified in ONE/THOUSANDTH of mm and being specified on the drawings same way.

ISO 14405 is very general upper-level standard, the best it can do is to say “keep number of decimals the same”.

Actual books of ISO 286-88 and/or ISO 406-87 may have the answer, but I don’t have a copy with me.
After all the tables (the most valuable part) of ISO 286 were reprinted everywhere including “Machinery’s” :)
 
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So, since there doesn't seem to be any specific wording to forbid the use of trailing zeros in ISO (at least from the current conversation), where is the source that does state this prohibition? ...or, is there really no rule at all, either way, in ISO?


Matt Lorono, CSWP
Product Definition Specialist, DS SolidWorks Corp
Personal sites:
Lorono's SolidWorks Resources & SolidWorks Legion
 
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fscuper,

I already mentioned 286 and 406 to pmarc. Maybe they go to finer detail.
But how exactly are you planning to “use” them? To use number of decimals for tolerancing you have to imply that 20.0 and 20.00 are NOT the same, while 8015 clearly states that 20.0 and 20.00 ARE the same.
It doesn’t forbid it, just makes it useless.
 
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406 is no more…

Replaced by… you guessed it - 14405 and new improved 129-1.

Unfortunately they also move stuff between the standards as well. Say, Independency and Envelope requirement went from 8015 to 14405.
I am quite sure that I saw the reference to 129 regarding number of decimals requirement somewhere.

Maybe it was the old 129? :)
 
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ISO probably doesn't give a crap about trailing decimals, because the main reason for using them is not applicable to ISO. Does ISO allow dimension tolerance schemes based on numbe of decimal places?
 
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Does ISO allow dimension tolerance schemes based on numbe of decimal places?
Click to expand...

It doesn't say it is not allowed.
 
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If anyone is interested, where does it say “you always have to put zero before the decimal point, if value is less than 1”, it’s in ISO 31-0. :)
 
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CH,
Is there anything in it stating that sign preceeding decimal fraction of dimension value shall always be "comma" and not "point" like in Y14.5?
 
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I think they are tired of arguing and now allow both.
(I don’t remember in which book – I already complained that they move some important statements from one standard to another :-()
What is strictly forbidden though, is using separator commas or point between groups of 3 digits like in 1,000,000.00.
I don't think I will miss it.
 
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