DEUTSCHE NORMAugust 1998

Rough castings of spheroidal graphite cast iron

General tolerances and machining allowances

(For replacement purposes only)

{

1685-1

Supersedes

October 1980 edition.

ICS77.140.80

Descriptors:General tolerances, machining allowances, castings,

spheroidal graphite cast iron.Gußrohteile aus Gußeisen mit Kugelgraphit – Allgemeintoleranzen,Bearbeitungszugaben (Nicht für 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

1Scope and field of application

This standard specifies general tolerances and machining allowances for rough castings of spheroidalgraphite 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 replacementpurposes. 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.

2Normative references

This standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies.DIN 1680-1DIN 1693-1DIN 7182-1

ISO 8062 : 1994

Rough castings – General tolerances and machining allowances – GeneralSpheroidal graphite cast iron – Unalloyed and low alloy gradesSizes, deviations, tolerances and fits – Basic concepts

Castings – System of dimensional tolerances and machining allowances

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3Concepts

See DIN 7182-1 and DIN 1680-1 for the terms ‘general tolerances’ and ‘tolerance grade’, and DIN 1680-1for a definition of ‘machining allowance’.

4

4.1

Tolerance grades

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 andcasting 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.

4.2Application of tolerance grades

Limit deviations shall be specified on the basis of the tolerance grades given in tables 1 and 2. Lineardimensions 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 ofDIN Deutsches Institut für Normung e.V., Berlin.

Beuth Verlag GmbH, D-10772Berlin, has the exclusive right of sale for German Standards (DIN-Normen).

Ref.No.DIN1685-1:1998-08

English price group06

Sales No.0106

11.98

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DIN1685-1:1998-08

4.3Nominal size ranges

The nominal size ranges shown in the tables for each tolerance grade have been selected on the basis of reliablemeasurement data. For sizes outside the range for a given grade, the next coarsest grade applies.

5Machining allowances

The machining allowance, BZ, is a function of the largest external dimension of the casting and is the same forall 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 intable 3 if the pattern equipment, casting procedure and machining procedure with regard to clamping surfacesand datum surfaces have been optimized, for example, for series production, as agreed between the customerand the foundry. These reduced values are shown in table 4.

For castings with a mass greater than 1000kg or a wall thickness greater than 50mm, the machining allow-ances shall be agreed between the manufacturer and client.

6Designation

Where both the tolerance grade and the machining allowance have been selected on the basis of the presentstandard, the designation of a grade GTB 17 tolerance (GTB 17) in conjunction with a machining allowance of2,5 for bottom and side surfaces in the die and of 3 for top surfaces (BZ 2,5/3), for example, shall be designatedas 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)*)

Toler-ancegrade

Nominal size range

OverOverOverOverOverOverOverOverOverOverOverOverOverOverOverOverOverOverOverOver

Up to

18

up toup toup toup toup toup toup toup toup toup toup toup toup toup toup toup toup toup toup toup to

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*)Irrespective of the values given in this table, the actual deviation of the linear dimensions of a casting shall in no case be greater thant25 % of the nominal size, rounded to one decimal place. This restriction is of particular relevance when applying the deviations inthe boxes enclosed by thick lines.

Nominal size range

Tolerance grade

Over

Up to6

up to

Overup to

Overup to

Overup to

Overup to

Overup to

Overup to

*)Irrespective of the values given in this table, the actual deviation of the linear dimensions of a casting shall inno case be greater than t25 % of the nominal size, rounded to one decimal place. This restriction is ofparticular 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.

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DIN1685-1:1998-08

Table 3:Machining allowances

Position ofsurface in mould

Nominal size range(based on the largestoverall dimension ofcasting)Machining

allowance, BZ

Overup to

Overup to

Overup to

Overup to

Overup to

Up to 50

Bottom, sideTop

Table 4:Reduced machining allowances, BZ (see clause 5)

Position ofsurface in die

Nominal size range(based on the largestoverall dimension ofcasting)Machining

allowance, BZ

Overup to

Overup to

Overup to

Up to 50

Bottom, sideTop

7Indicating 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 recommendedthat 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 beconverted 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

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Tolerance group

Over

Up to

Overup to

Overup to

Overup to

18

External dimensionsInternal dimensions

up to

For centreline distances, the limit deviations specified for internaldimensions shall be used.

Table 6:Limit deviations for thicknesses

on existing drawings

Nominal size range

Tolerance group

Over

Up to

Overup to

Overup to

6up to

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DIN1685-1:1998-08

8Indicating machining allowances on existing drawings

The machining allowances specified in this standard only apply to drawings on which general tolerances inaccordance 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 replacementpurposes.

Other relevant standards

DIN 1680-2Rough castings – General tolerances

DIN 1690-1Technical delivery conditions for castings of metallic materials – General

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