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Appendix
NTN
Ordinary tolerance for steel castings
JIS B 0412
This Standard specifies the ordinary tolerances for the
length and as-casted wall thickness (hereinafter referred
to as "ordinary tolerance") of steel castings casted by
sand molds.
Ordinary tolerance shall be indicated by either one of
the following methods (1) and (2).
(1) Numerical value table for each dimensional division
(2) Applicable Standard No. and tolerance class
Ex. JIS B0412, Medium Class
Tolerance class: The ordinary tolerance class shall be
three classes of "Fine Class", "Medium Class" and
"Coarse Class".
Dimension-A for draft angle
Dimensional divisionl
18 incl.
Over 18 50 incl.
Over 50 120 incl.
Over 120 250 incl.
Over 250 400 incl.
Over 400 630 incl.
Over 630 1000 incl.
Unit : mm
Dimension
A (max)
1.4
2
2.8
3.5
4.5
5.5
7
Remarks: l means l1 and l2 in the above sketch.
A means A1, A2 in the above sketch.
draft A1
angle l1
l1
A1
Specified length
Specified wall thickness
A2
draft
angle
l2
A2
l2
Ordinary tolerance for length
Dimensional division
class
120 and less
Over 120 - 315 incl.
Over 315 - 630 incl.
Over 630 - 1250 incl.
Over 1250 - 2500 incl.
Over 2500 - 5000 incl.
Over 5000 - 10000 incl.
18 and less
Over 18 - 50 incl.
Over 50 - 120 incl.
Over 120 - 250 incl.
Over 250 - 400 incl.
Over 400 - 630 incl.
Over 630 - 1000 incl.
Fine class
1.8
2.5
3.5
5
9
Ordinary tolerance for wall thickness
Dimensional division
1.4
2
Medium class Coarse class
2.8
4
5.5
8
14
20
2.2
3
4.5
5.5
7
9
Unit : mm
4.5
6
9
12
22
35
63
Unit : mm
class Fine class Medium class Coarse class
3.5
5
7
9
11
14
18
Remarks: “Fine Class” shall be applied to minor steel castings subjected to
special accuracy.
Ordinary tolerance for aluminum alloy castings
JIS B 0414
This Standard specifies the ordinary tolerances
(hereinafter referred to as ordinary tolerance) for the
length and wall thickness of aluminum alloy castings
(hereinafter referred to as castings molded by sand
mold and mold. However, this Standard is not applied to
castings molded by precision molds using Lost Wax
Method, etc.
Ordinary tolerance shall be indicated by either one of
the following methods (1) and (2).
(1) Numerical value table for each dimensional division
(2) Applicable Standard No. , classification and
tolerance class by casting mold
Ex. JIS 0414 , Sand mold, Coarse Class
Definition of terms: The terms used in this Standard are
as defined below.
Mold split surface: Two or more splitted surfaces of
mold for drafting a model or a castings out of a
casting mold.
Length including
mold split surface
Length excluding mold
split surface
Mold split surface
C-14