DEUTSCHE NORM August 1998
Rough castings of spheroidal graphite cast iron
General tolerances and machining allowances
DIN
(For replacement purposes only) 1685-1
ICS 77, 140.80 Supersedes
October 1980 edition.
Descriptors: General tolerances, machining allowances, castings,
spheroidal graphite cast iron.
Gulrohteile aus Guf3eisen mit Kugelgraphit - Allgemeintoleranzen,
Bearbeitungszugaben (Nicht fur Neukonstruktionen)
In keeping with current practice in standards published by the International Organization for Standardization
(ISO), a comma has been used throughout as the decimal marker.
Dimensions in mm
1 Scope and field of application
This standard specifies general tolerances and machining allowances for rough castings of spheroidal
graphite cast iron which are subject to the technical delivery conditions laid down in DIN 1693-1.
Users of this standard should note that it now only applies to castings used for repair and replacement
purposes. New designs are covered by ISO 8062 :1994.
Owing to the lack of empirical data, general tolerances have not been specified here for angular dimensions.
If angles are to meet accuracy requirements, these shall be indicated as individual tolerances.
2 Normative references
This standard incorporates, by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text, and the titles of the publications are
listed below. For dated references, subsequent amendments to or revisions of any of these publications
apply to this standard only when incorporated in it by amendment or revision. For undated references, the
latest edition of the publication referred to applies.
DIN 1680-1 Rough castings - General tolerances and machining allowances - General
DIN 1693-1 Spheroidal graphite cast iron - Unalloyed and low alloy grades
DIN 7182-1 Sizes, deviations, tolerances and fits - Basic concepts
ISO 8062 : 1994 Castings - System of dimensional tolerances and machining allowances
3 Concepts
See DIN 7182-1 and DIN 1680-1 for the terms `general tolerances' and `tolerance grade', and DIN 1680-1
for a definition of `machining allowance'.
4 Tolerance grades
4.1 Dimensional deviations
For castings of spheroidal graphite cast iron, dimensional deviations are largely dependent on
a) the dimensional accuracy of the pattern, the degree of shrinkage dependent on the material type and
casting configuration, the care taken during moulding and casting, and the moulding and casting equip-
ment used based on the batch size;
b) the nominal sizes.
4.2 Application of tolerance grades
Limit deviations shall be specified on the basis of the tolerance grades given in tables 1 and 2. Linear
dimensions and thickness shall be specified for the same grade; for exceptions see DIN 1680-1.
Continued on pages 2 to 4.
Translation by DIN-Sprachendienst.
In case of doubt, the German-language original should be consulted as the authoritative text.
© No part of this translation may be reproduced without the prior permission of Ref. No. DIN 1685-1 : 1998-08
DIN Deutsches Institut fur Normung e. V., Berlin. English
price group 06 Sales No. 0106
Beuth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). 11 98
Page 2
DIN 1685-1 :1998-08
4.3 Nominal size ranges
The nominal size ranges shown in the tables for each tolerance grade have been selected on the basis of reliable
measurement data. For sizes outside the range for a given grade, the next coarsest grade applies.
5 Machining allowances
The machining allowance, BZ, is a function of the largest external dimension of the casting and is the same for
all tolerance grades (cf. table 3); see DIN 1680-1 for exceptions.
For sizes up to 500 mm, machining allowances may be reduced to approximately half the values specified in
table 3 if the pattern equipment, casting procedure and machining procedure with regard to clamping surfaces
and datum surfaces have been optimized, for example, for series production, as agreed between the customer
and the foundry. These reduced values are shown in table 4.
For castings with a mass greater than 1 000 kg or a wall thickness greater than 50 mm, the machining allow-
ances shall be agreed between the manufacturer and client.
6 Designation
Where both the tolerance grade and the machining allowance have been selected on the basis of the present
standard, the designation of a grade GTB 17 tolerance (GTB 17) in conjunction with a machining allowance of
2,5 for bottom and side surfaces in the die and of 3 for top surfaces (BZ 2,5/3), for example, shall be designated
as follows:
Tolerance and machining allowance DIN 1685 - GTB 17 - BZ 2,5/3
See DIN 1680-1 for other examples of designations.
Table 1 : Limit deviations for linear dimensions
(length , width, height , centreline distance , diameter , radius)*)
Nominal size range
Toler-
ance Over Over Over Over Over Over Over Over Over Over Over Over Over Over Over Over Over Over Over Over
Upto 18 30 50 80 120 180 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 6300
grade 18 up to up to up to up to up to up to up to up to up to up to up to up to up to up to up to up to up to up to up to up to
30 50 80 120 180 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 6300 10000
GTB20 ±4,5 ±7,5 ±8 +10 ±11 ±11 ±12 ±13 ±14
±8,5 ±9 ±15 ±16 ±18 ±19 ±21 ±23 ±25 ±27 ±33 ±39
VGTB19 ±4,5 ±4,7 +5 ±5,5 ±6 +7 +7,5
±6,5 .±4,4. +8 ±8,5 ±9,5 ±10 ±11 ±12 ±13 ±14 ±15 ±17 ±19 ±22 ±26
±2,9._. ±4,7
+.4,1.
GT818 +3 +3,2 ±3,4 ±3,7 +5 ±5,5 ±6 ±6,5 ±7 ±7,5 ±8,5 ±9 ±10 ±11 ±12 ±14 ±17
±2 ±21 +23 +25 +27 +29 +31 +33 +35 ±38 +41 +44 +49 ±55 ±6 ±65 ±7 _ -
GTB17 +18 ±1,9
GTB 16 ±1,1 ±1,2 ±1,3 ±1,4 ±1,5 ±1,6 ±1,8 ±1,9 ±2 ±2,1 ± 2,3 ± 2,4 ± 2,6 ± 2,8 - -
GTBI5 ± 0,$5 :^ 0,95 -^ 1 ± 1, ±1,2 + 1,3 ±1,4 ± 1,5 ± 1,6 ± 1,7 ±1,8 ± 1,9 _ _
*) Irrespective of the values given in this table, the actual deviation of the linear dimensions of a casting shall in no case be greater than
±25 % of the nominal size, rounded to one decimal place. This restriction is of particular relevance when applying the deviations in
the boxes enclosed by thick lines.
Table 2 : Limit deviations for thicknesses (wall, web and rib thicknesses )*), **)
Nominal size range
Over Over Over Over Over Over Over
Tolerance grade Up to 6 10 18 30 50 80 120
6 upto upto upto upto upto upto upto
10 18 30 50 80 120 180
GTB20 -- ^- ±7,5 ±11 ±12 +13 ±14
GBT 19 -- - ±4,5 ±7,5 ^ ±8 ± 8,5 ±9 ±10
GTB 18 _ - ±2 +4,5 ±4,7 ±5 ± 5,5 ±6 ± 6,5
GTB 11 ± 1,5 ± 2,5 ± 2,9 ±3 ± 3,2 ± 3,4 ± 3,7 _____
GTB 16 ±1,5 + 1,8 ±1,8 ±1,9 ±2 ± 2,1 ± 2,3 -
GTB 15 _.^..._-...__ ±0,95 ±1 ±1,1 ±1,2 + 1,3 + 1,4 - .-
*) Irrespective of the values given in this table, the actual deviation of the linear dimensions of a casting shall in
no case be greater than ±25 % of the nominal size, rounded to one decimal place. This restriction is of
particular relevance when applying the deviations in the boxes enclosed by thick lines.
**) The values specified here are taken from the deviations specified for one full grade coarser in table 1.
Page 3
DIN 1685-1 :1998-08
Table 3 : Machining allowances
Nominal size range
Position of (based on the largest Over 50 Over 120 Over 250 Over 500 Over 1000
surface in mould overall dimension of Upto 50
up to 120 up to 250 up to 500 up to 1000 up to 2500
casting)
Bottom, side Machining 2 2,5 3 3,5 4 6
..
allowance, BZ
Top 25
, 3 4 5 7 8
Table 4: Reduced machining allowances , BZ (see clause 5)
Nominal size range
Position of (based on the largest Over 50 Over 120 Over 250
to 50
surface in die overall dimension of upto 120 upto 250 upto 500
casting)
Bottom, side Machining 1 1 1,5 1,5
a ll owance, BZ -
Top 1,5 1,5 1,5 2
7 Indicating general tolerances on existing drawings
If an existing drawing does NOT refer to the tolerance groups specified in the 1962 edition of this standard
(which is no longer valid), then the tolerance grades given in tables 1 and 2 do not apply. It is recommended
that a grade suitable for the casting in question be indicated on such drawings.
If an existing drawing DOES refer to the previously valid tolerance groups, it is recommended that these be
converted to the tolerance grades specified in tables 1 and 2 of the present standard. If this is not possible,
the permissible limit deviations are to be taken from tables 5 and 6 below.
Tables 5 and 6 do NOT apply to new drawings.
Table 5 : Limit deviations for linear dimensions on existing drawings
Nominal size range
Tolerance group Over Over Over Over
Up to 18 50 180 500
18 upto upto upto upto
50 180 500 1250
+3 +5 +7 +9
External dimensions +..12 ^. 2 _ 3,5 _5 .. 7
A
Internal dimensions +_2
1 +2 + 3,5 +5 +7
_3 _5 _7 ..0
+1,2 +2 +4 +6 +8
External dimensions
_ 1,5 _ 2,5 .r 3,5 -5
B
Internal dimensions +1 2 + 1,5 + 2,5 + 3,5 +5
_2 _4 _6 _8
For centreline distances, the limit deviations specified for internal
dimensions shall be used.
Table 6 : Limit deviations for thicknesses
on existing drawings
Nominal size range
Tolerance group Over Over Over
Up to 6 18 50
6 upto upto upto
18 50 120
A ± 1,5 ± 2,5 ± 3,5 ± 4,5
B ±1 ±2 ±2,5 ±3,5
Page 4
DIN 1685-1 :1998-08
8 Indicating machining allowances on existing drawings
The machining allowances specified in this standard only apply to drawings on which general tolerances in
accordance with clause 4 and tables 1 and 2 of this standard are indicated.
Previous editions
DIN 1685-1: 1962-04,1974-08, 1978-07, 1980-10.
Amendments
As compared with the October 1980 edition, the standard now applies only to castings used for replacement
purposes.
Other relevant standards
DIN 1680-2 Rough castings - General tolerances
DIN 1690-1 Technical delivery conditions for castings of metallic materials - General
