ISO/TC 213 N 560-11 (Poland)
Document: DIS 286-1
Date: 2003-04-29
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MB1
Clause No./
Subclause No./
Annex
(e.g. 3.1)
Paragraph/
Figure/Table/
Note
(e.g. Table 1)
Type
of
comment2
Comment (justification for change) by the MB
Proposed change by the MB
Secretariat observations
on each comment submitted
PL
3.2.8
PL
3.2.8
PL
3.2.8
PL
te
See our comment on 3.2.8.1.
Modify the definition: “difference between the
upper and lower limits of size”.
NOTE 2
te
The term “tolerance zone” is not used in this standard.
“Tolerance zone” should be replaced by “tolerance
interval”.
NOTE 3
te
See our comment on 3.2.8.1.
Modify the text: “For the calculation limits of size
can be replaced by the upper limit deviation and
the lower limit deviation”.
3.2.8.1
te/ge
It seems that “tolerance limit” means here exactly the
same as “limit of size” according to 3.2.4. The term
“tolerance limit” was not used in CD 286-1. It should be
noted that the standard deals only with sizes (see Scope),
not with “characteristics” in general.
Delete 3.2.8.1, replace in the whole document
“tolerance limit” by “limit of size”.
PL
3.3.2, 3.3.2.1,
3.3.2.2
te
The definitions are incomplete. Interference is the
absolute value of the hole and shaft sizes. See our
analysis of problems related to fit and its characteristics
given in an annex.
Add “absolute value of …” in definitions of
interference.
PL
3.3.3
te
The definition of fit is not clear because the term
“assembly” is ambiguous. For engineers it means a set of
machine parts mounted together. “Assembly of features”,
mentioned here, has not been defined and this term can
confuse users of the standard.
A fit is not just an assembly of two machine parts (e.g., a
bush and a mandrel) but it is a property (characteristic) of
such assembly. Therefore, the definition in the CD was
much better.
The NOTE is very important and this pre-condition should
be also considered in Annex B.
Adopt the definition according to CD 286-1, 3.3.3.
(NOTE is OK!)
PL
3.3.3.4
te
The calculation of the span explained here is based on
two different meanings of interference (see our analysis
annexed). The result of calculating the span of an
interference fit, according to the given rule, is wrong: see
example in B.2, where – to get the correct result –
another formula was used (minimum interference –
maximum interference).
The 2nd sentence should read: “The span of a
transition fit is the sum of the maximum clearance
and the maximum interference”.
NOTE 2
1 MB = Member body (enter the ISO 3166 two-letter country code, e.g. CN for China; comments from the ISO/CS editing unit are identified by **)
2 Type of comment: ge = general
te = technical
ed = editorial
NOTE
Columns 1, 2, 4, 5 are compulsory.
page 1 of 3
ISO electronic balloting commenting template/version 2001-10
ISO/TC 213 N 560-11 (Poland)
Document: DIS 286-1
Date: 2003-04-29
1
2
(3)
4
5
(6)
(7)
MB1
Clause No./
Subclause No./
Annex
(e.g. 3.1)
Paragraph/
Figure/Table/
Note
(e.g. Table 1)
Type
of
comment2
Comment (justification for change) by the MB
Proposed change by the MB
Secretariat observations
on each comment submitted
PL
4.3
te
In technical documentation the values of limit deviations
are usually expressed in mm.
Add information, e.g.: “In practical applications
limit deviations should be given in millimetres”.
PL
5.1
te
Adoption of the pre-condition mentioned in 3.3.3 allows
for performing calculations of clearances and
interferences without using limits of sizes, but basing only
on limit deviations.
Therefore, an additional subclause on calculation of fits
would be useful.
Add:
5.1.3 Calculation of fits
If the nominal sizes of the hole and the shaft are
identical (see 3.3.3), in calculations of clearances
and interferences the limit deviations instead of the
limits of sizes can be applied.”
PL
5.1.1
EXAMPLE
ed
Error in the 2nd designation of the fit.
PL
5.2.1
1st para
ed
The term “element” does not seem to be correct here.
Instead of “element” use e.g. “factor”.
PL
A.2
2nd
ed
The modifier E should be written in a circle (not in
parentheses).
Correct the code: 30H6
PL
B.1
te/ge
See the comment concerning calculation of fits (5.1, new
subclause 5.1.3).
Modify all calculations basing them on limit
deviations (not using limits of sizes). E.g., in
EXAMPLE 1:
PL
B.1
PL
B.2
para
EXAMPLE
1, 4th line
Correct the code; it shall read: 52
H7
g6

lower hole deviation – upper shaft deviation =
0 – (–0,025) = 0,025 mm

upper hole deviation – lower shaft deviation =
+0,035 – (–0,025) = 0,089 mm
ed
Spelling error
lower
te
According to the definition of span (see 3.3.3.4), span of a
fit is arithmetic sum of the size tolerances of hole and
shaft – and this definition, preferably, should be applied
here.
Change the calculations, e.g. for the clearance fit:
0,039 mm + 0,025 mm = 0,064 mm.
If another way of span calculation is to be
presented (not based on definition!), in the cases
of transient and interference fits the calculations
should read:
0,008 mm + 0,033 mm = 0,041 mm
0,059 mm – 0,018 mm = 0,041 mm.
1 MB = Member body (enter the ISO 3166 two-letter country code, e.g. CN for China; comments from the ISO/CS editing unit are identified by **)
2 Type of comment: ge = general
te = technical
ed = editorial
NOTE
Columns 1, 2, 4, 5 are compulsory.
page 2 of 3
ISO electronic balloting commenting template/version 2001-10
ISO/TC 213 N 560-11 (Poland)
Document: DIS 286-1
Date: 2003-04-29
1
2
(3)
4
5
(6)
(7)
MB1
Clause No./
Subclause No./
Annex
(e.g. 3.1)
Paragraph/
Figure/Table/
Note
(e.g. Table 1)
Type
of
comment2
Comment (justification for change) by the MB
Proposed change by the MB
Secretariat observations
on each comment submitted
Annex to the Polish comments on ISO/DIS 286-1 (analysis prepared Prof. S. Bialas, ISO/TC 213/WG 12 member)
There is no doubt that the method of calculating clearances and interferences presented in Annex B is clear and correct. But if we consider subclause 3.3 (in particular – 3.3.2) and try to do
the same calculations as e.g. in Example 3 in B.1, but using the relationships given directly in 3.3.2, the results obtained will be quite different than in B.1.
According to 3.3.2.1:
maximum interference = – 0,059 mm
minimum interference = – 0,018 mm
– end of calculation!
According to B.1:
Interference of a given fit is calculated in two steps:
1.
Computing the differences of limit sizes of hole and shaft.
2.
Interpreting the results – taking their absolute values:
maximum interference = 0,059 mm
minimum interference = 0,018 mm
Therefore two different “interferences” can be distinguished:

according to 3.3.2.1, a quantity of negative value; let it be named interference*

according to B.1, a quantity of positive value; let it be named interference**.
If interference* is considered, the following contradictions can be observed:

The terms “maximum interference” (3.3.2.2) and “minimum interference” (3.3.3.1) are illogical, because the first is lesser than the second (–0,059 mm < –0,018 mm);

The span of an interference fit (3.3.3.4, NOTE 2) is negative: –0,059 mm – (–0,018 mm) = – 0,041 mm (note that in the case of transient fit the result will be correct). In B.2 another
formula was used; to get the correct result, the span was calculated as difference of minimum interference* – maximum interference*.
So it is obvious that in fact interference* is not the interference yet. It is only a kind of “semi-product” and the final quantity is interference**, after taking the absolute value of interference*.
Conclusion – the correct definitions
In 3.3.2: the absolute value of the difference between …
In 3.3.2.1: in an interference fit, the absolute value of the difference between …
In 3.3.2.2: in an interference or transition fit, the absolute value of the difference between …
In 3.3.3.4, NOTE 2: The span of a transition fit is the sum of the maximum clearance and the maximum interference.
1 MB = Member body (enter the ISO 3166 two-letter country code, e.g. CN for China; comments from the ISO/CS editing unit are identified by **)
2 Type of comment: ge = general
te = technical
ed = editorial
NOTE
Columns 1, 2, 4, 5 are compulsory.
page 3 of 3
ISO electronic balloting commenting template/version 2001-10