ISO 2768 General Tolerances: Class Tables, Title Block Wording, and the 2026 Revision

ISO 2768 is the ISO general tolerance standard that fills in permissible deviations for any linear or angular dimension on a drawing that carries no individual tolerance. In 2026 the standard sits in an unusual state. ISO 2768-1:1989, the linear and angular part, remains current and entered pre-publication (stage 60.00) as ISO 2768 Edition 2 on 2 June 2026 under ISO/TC 213. ISO 2768-2:1989, the geometrical part, was cancelled and replaced by ISO 22081:2021, which brings general geometrical and general size specifications into the GPS framework of ISO 8015. A drawing released today can still carry ISO 2768-mK, but the K half references a withdrawn document, and buyers writing new title blocks now face a choice between three valid wordings. This guide covers the four tolerance classes with full deviation tables, the three title-block wordings you can legally use, the eight rules that replace the old K/H/L system, and the rejection clause that decides who pays when a feature drifts.

1. Where ISO 2768 stands in 2026

ISO 2768-1:1989 is still in force. ISO 2768-2:1989 was withdrawn in 2021. A new single-part ISO 2768 Edition 2 entered pre-publication on 2 June 2026 and is expected to replace the 1989 linear and angular part.

1.1 The two-part standard split

The 1989 edition of ISO 2768 was published in two parts that share a number but no longer share a status. Part 1 covers linear and angular sizes and remains published under ISO/TC 213. Part 2 covered geometrical characteristics for straightness, flatness, perpendicularity, symmetry, and circular run-out; ISO 22081:2021 cancels and replaces it and brings general geometrical specifications into the ISO 8015 GPS framework. Any new drawing that references ISO 2768-2 for form or orientation defaults now points at a document with no active technical content. Surface roughness never sat inside 2768 at all and follows surface roughness is not covered by general tolerances.

Table 1. Standards status snapshot, July 2026.

Standard	Scope	Status
ISO 2768-1:1989	Linear and angular dimensions, four classes f, m, c, v	Published, current
ISO 2768-2:1989	Geometrical features, three classes H, K, L	Withdrawn, replaced by ISO 22081:2021
ISO 22081:2021	General geometrical and general size specifications under ISO 8015	Published, current
ISO 2768 Edition 2	Single-part successor to 2768-1	Stage 60.00, expected publication mid to late 2026

Engineering note. According to Dewey Wu, more than eight out of ten drawings EPOC CRAFTER received in the twelve months to July 2026 still carried ISO 2768-mK in the title block. Half of that callout, the K half, now references a withdrawn document, and shops read it by memory, not against the current standard.

1.2 What changed on 2 June 2026

Stage 60.00 is the ISO code for pre-publication approval. On 2 June 2026 the successor draft to ISO 2768-1 reached that stage, meaning the technical content is fixed and the document is queued for release under the new name Geometrical product specifications (GPS), Dimensional tolerancing, Tolerance limits for general specification of linear and angular sizes. The suffix -1 disappears. The linear and angular deviation tables move into the GPS system alongside ISO 22081, which means one drawing standard family, not two disconnected 1989 documents.

Table 2. ISO 2768 timeline and effect on title-block wording.

Date	Event	Effect on your title block
1989	ISO 2768-1 and 2768-2 published	Two-letter callout ISO 2768-mK became standard
2021	ISO 22081 cancels ISO 2768-2	K/H/L geometrical classes lost their standard basis
2 June 2026	ISO 2768 Edition 2 reaches stage 60.00	Single-part successor confirmed, publication pending
Publication of Edition 2 (expected 2026)	ISO 2768-1:1989 to be superseded	New drawings should cite the Edition 2 designation

Engineering note. Between the withdrawal of Part 2 in 2021 and the publication of Edition 2, three title-block wordings are simultaneously defensible. Choosing between them is the subject of Section 4, the Title-Block Migration Ladder.

2. ISO 2768-1:1989 tolerance class tables

ISO 2768-1 gives four classes: f fine, m medium, c coarse, v very coarse. The tables cover linear sizes from 0.5 mm to 4000 mm, external radii and chamfers to over 6 mm, and angular dimensions to over 400 mm on the shorter side.

2.1 Permissible deviations for linear dimensions

Table 3 of this article, transcribed from Table 1 of ISO 2768-1, applies to external sizes, internal sizes, step sizes, diameters, distances, and any linear dimension not carrying an individual tolerance. Values are in millimetres. Deviations are symmetric plus or minus. Every row is transcribed from the standard without reduction.

Table 3. Permissible deviations for linear dimensions (except broken edges), ISO 2768-1:1989.

Nominal size range (mm)	f fine	m medium	c coarse	v very coarse
0.5 up to 3	±0.05	±0.1	±0.2	not applicable
over 3 up to 6	±0.05	±0.1	±0.3	±0.5
over 6 up to 30	±0.1	±0.2	±0.5	±1
over 30 up to 120	±0.15	±0.3	±0.8	±1.5
over 120 up to 400	±0.2	±0.5	±1.2	±2.5
over 400 up to 1000	±0.3	±0.8	±2	±4
over 1000 up to 2000	±0.5	±1.2	±3	±6
over 2000 up to 4000	not applicable	±2	±4	±8

Two rows are easy to miss. The f fine class does not extend beyond 2000 mm, so any drawing that specifies ISO 2768-f on a 3 metre weldment carries an internal contradiction. The v very coarse class does not cover 0.5 to 3 mm, so a stamped micro feature cannot default to v. In both cases the individual tolerance must be written next to the dimension. For decisions on which features earn an individual tolerance and which stay under the general class, see how to tolerance a CNC drawing.

2.2 Permissible deviations for external radii and chamfer heights

Table 4 covers external radii on broken edges and chamfer heights. The deviation values are considerably wider than Table 3 for the same nominal size because these features rarely carry a functional consequence proportional to a tight class.

Table 4. Permissible deviations for external radii and chamfer heights, ISO 2768-1:1989.

Nominal size range (mm)	f fine	m medium	c coarse	v very coarse
0.5 up to 3	±0.2	±0.2	±0.4	±0.4
over 3 up to 6	±0.5	±0.5	±1	±1
over 6	±1	±1	±2	±2

Engineering note. In the f and m classes the values in Table 4 are identical. A drawing that upgrades linear tolerance from m to f gains nothing on external radii and chamfers. If a chamfer edge is functional, for example a sealing bevel or a mating lead in, write the individual tolerance next to that dimension. Relying on the class to tighten a chamfer is a wasted line in the title block.

2.3 Permissible deviations for angular dimensions

Table 5 applies to angular dimensions including right angles (90°) unless the drawing separately references ISO 2768-2 or, on modern drawings, ISO 22081. Deviations are given in degrees and minutes. The nominal length that drives the deviation is the shorter side of the angle concerned, not the angle itself.

Table 5. Permissible deviations for angular dimensions, ISO 2768-1:1989.

Shorter side length (mm)	f fine	m medium	c coarse	v very coarse
up to 10	±1°	±1°	±1°30′	±3°
over 10 up to 50	±0°30′	±0°30′	±1°	±2°
over 50 up to 120	±0°20′	±0°20′	±0°30′	±1°
over 120 up to 400	±0°10′	±0°10′	±0°15′	±0°30′
over 400	±0°5′	±0°5′	±0°10′	±0°20′

Notice that the f and m columns are identical across all five length bands. Choosing between them changes nothing for angular features. The gap only opens when you drop to c or v. A shop reading ISO 2768-m expects the same angular tolerance a shop reading ISO 2768-f expects.

2.4 Nominal sizes below 0.5 mm

For nominal sizes below 0.5 mm, ISO 2768-1 requires the deviation to be indicated adjacent to the relevant nominal size. The general class does not apply. This clause matters on micro machined features, thin wall sheet metal cutouts, and small hole diameters near the resolution limit of a callout, where a class based default would either be too tight for the process or too loose for the function. A feature at 0.4 mm needs its own tolerance on the drawing, no exceptions.

3. Title-block wording: what you write and what it means

Three title-block wordings are legally valid in July 2026. Legacy `ISO 2768-mK` still parses, but the K half references a withdrawn standard. A split wording separates dimensional and geometrical clauses. A full ISO 22081 wording moves everything into the GPS system.

3.1 The legacy wording

The wording most drawings still carry today is the two-letter form defined in Clause 5 of ISO 2768-1:1989, placed in or near the title block.

General tolerances ISO 2768-mK

The lowercase m selects the medium class from Part 1, Tables 1 to 3. The uppercase K selected the medium geometrical class from Part 2 for straightness, flatness, perpendicularity, symmetry, and circular run-out. Since ISO 2768-2:1989 was withdrawn in 2021, the K half no longer references an active standard. A drawing released today with ISO 2768-mK is not defective, because the citation still parses, but the second half of the callout has no current normative basis. Any dispute over K-class deviations now runs against a withdrawn document. For untoleranced diameters that require actual fit control, ISO 2768 is not the right document; use ISO 286 fits for shaft and hole.

3.2 The split wording

The split wording keeps ISO 2768-1 for the linear and angular tables and switches the geometrical half to ISO 22081. It is the cleanest interim option for drawings released between now and the appearance of ISO 2768 Edition 2.

General tolerances ISO 2768-m
General geometrical tolerances ISO 22081

The m half continues to cite Part 1 tables 1 through 3 unchanged. The second line points at the current geometrical framework. Under ISO 22081 Rule B, the reference must appear in or near the title block or in the product definition data set, so a text line on the drawing satisfies the rule. Linear callouts stay in a form every shop already reads. Geometrical defaults stop referencing a withdrawn document.

Engineering note. A supplier who does not hold ISO 22081 will fall back on ISO 8015 default rules for any feature that ISO 22081 would have controlled. The split wording still delivers a legally defensible drawing; whether the shop can act on it comes down to which standards they hold.

3.3 The full ISO 22081 wording

ISO 22081 Rule C requires the general geometrical specification to be indicated with a surface profile characteristic, and Rule G requires the general size specification to be indicated with a linear size, an angular size, or both. Figure 1 of the standard shows the complete wording. Transcribed from the standard:

General tolerances ISO 22081
⌓ 0.5  A  B  C
Linear sizes: ±0.25 Ⓔ
Angular sizes: ±0.5°

Four elements pack into this block. The header line cites the standard. The surface profile frame ⌓ gives the geometrical tolerance zone value, 0.5 mm in the Figure 1 example, referenced to a datum system A-B-C. The linear line gives the general size deviation with the envelope requirement modifier Ⓔ per ISO 14405-1. The angular line gives the general angular deviation. All four are needed. Omit the datum letters and Rule F fails. Omit the linear line and drawings default only to the geometrical specification, leaving untoleranced sizes without a general rule (see ISO 22081 Figure B.3 for the missing size case).

Engineering note. The tolerance value inside the surface profile frame is a single number the drafter chooses, not a class code. There is no H, K, or L equivalent in ISO 22081. This is the point competitors keep missing: the standard does not provide a fixed numerical table. Annex A of ISO 22081 is informative and shows one example of a variable value table keyed to nominal size, nothing more. Every drawing sets its own value.

4. The Title-Block Migration Ladder

Four rungs describe every drawing you might release in 2026, from a straight legacy callout to a full ISO 22081 wording. Identify your current rung, then decide whether the next release stays or steps up.

4.1 Rung 1. Legacy Only

Rung 1 is the drawing that still writes General tolerances ISO 2768-mK and nothing else. Roughly eight out of ten drawings EPOC CRAFTER received in the twelve months to July 2026 sit on this rung. The wording parses on any shop floor. Half of it, the K reference to Part 2, points at a document withdrawn in 2021. Rung 1 stays defensible for existing production drawings that no one is planning to reissue. It stops being defensible on new drawings released after ISO 2768 Edition 2 publication, because the -1 suffix will disappear from the ISO catalogue.

4.2 Rung 2. Split Notation

Rung 2 keeps ISO 2768-m and adds ISO 22081 as a second line for geometrical control. It is the practical stepping stone for shops that want to fix the K half without redoing every general tolerance decision on the drawing. The linear and angular deviations continue to come from Tables 1 to 3 unchanged, so quoting, inspection routines, and CMM programs need no rewrite. The geometrical half now points at a current standard, which lets Rule E and Rule F apply properly for datum locking. For manufacturing planning against ISO 2768-m bands and the tighter individual features they wrap around, see CNC machining capabilities under ISO 2768-m.

4.3 Rung 3. Modern Split

Rung 3 replaces the linear reference with the Edition 2 designation once it is published, while retaining ISO 22081 for the geometrical clause. The wording becomes something like General tolerances ISO 2768:20xx / General geometrical tolerances ISO 22081, where 20xx is the publication year of Edition 2. Rung 3 removes the last citation to a 1989 document and is the correct rung for new drawings released after Edition 2 publication, before any team wide switch to the full ISO 22081 format.

4.4 Rung 4. Full ISO 22081

Rung 4 drops the two line split and adopts the four element block shown in ISO 22081 Figure 1. One line cites the standard. One geometrical frame gives the surface profile tolerance zone against a datum system. One line gives the linear size deviation, one gives the angular deviation. Rung 4 removes the classification letters entirely. Drawings pick their own numerical values for each general specification, which forces the drafter to think about actual functional tolerance instead of defaulting to m by habit. Rung 4 is the endpoint for drawings integrated with a 3D CAD model where TEDs propagate through the model tree.

4.5 Where you stand and where to move next

The four rungs sit on a single migration line. Rung 1 is where most drawings start. Rung 2 is the safe step up during 2026. Rung 3 becomes available on publication of Edition 2. Rung 4 is the target for teams committing to GPS based drafting. Two rules govern the step: do not move rungs mid-project, and on a new project, start at the highest rung your suppliers can read. A Rung 4 drawing sent to a shop that has never opened ISO 22081 will produce parts to whatever default that shop applies, not to what your title block asked for.

Engineering note. According to Dewey Wu, fewer than one in ten drawings EPOC CRAFTER received in the same twelve month window sat above Rung 1. The migration cost is not the drafting change but the supplier requalification. A Rung 2 rollout across a supplier base of ten shops requires each shop to confirm it holds ISO 22081 and reads it correctly on Rule E datum locking, which adds two to four weeks to the transition. Design engineers who assume the label change alone completes the migration discover the gap on the first inspection report.

Table 6. The Title-Block Migration Ladder.

Rung	Wording used	Standards status	When to sit here
1 Legacy Only	ISO 2768-mK	Part 1 current, Part 2 withdrawn 2021	Existing production drawings not scheduled for revision
2 Split Notation	ISO 2768-m + ISO 22081	Both halves cite current standards	New drawings in 2026 before Edition 2 publication
3 Modern Split	ISO 2768:20xx + ISO 22081	Edition 2 replaces -1 designation	New drawings after Edition 2 publication
4 Full ISO 22081	ISO 22081 four element block	Single GPS reference, no letter classes	Drawings integrated with 3D CAD model, TED-driven

5. The eight rules that replace ISO 2768-2

ISO 22081 defines general geometrical and general size specifications through eight rules labelled A to H. Three of them decide whether the standard produces controlled parts or ambiguous ones: Rule C on surface profile, Rules E and F on datums, and Rule H on feature identification.

5.1 What the datum system must do (Rules E and F)

Rule E of ISO 22081 requires a datum system to be established in order to specify a general geometrical specification. Rule F requires that datum system to lock all degrees of freedom necessary to locate the tolerance zones defined by the specification. A drawing that cites General tolerances ISO 22081 / ⌓ 0.5 A B C puts a surface profile tolerance of 0.5 mm on every integral feature, but the tolerance zones only exist once A, B, and C are defined as datum features. Without the datum letters, Rule F fails and the general geometrical specification carries no controlled meaning.

The datum system does not have to include three datums or lock all six degrees of freedom. Note 1 to Rule F allows partial locking when the general specification only needs partial location. A rotationally symmetric part with a general specification tied to the axis of revolution can use two datums. For decisions on when a general specification is enough and when an individual feature control frame is required.

Engineering note. The datum features named in the general geometrical specification themselves need individual specifications, because Rule D excludes them from the general rule. A drawing that names A, B, and C in the header block without individually specifying A, B, and C somewhere on the part is incomplete under ISO 22081.

5.2 Why the general geometrical specification must be surface profile (Rule C)

Rule C requires the general geometrical specification to be indicated with a surface profile characteristic, shown by the ⌓ symbol. No other geometrical characteristic works as the general specification. Straightness, flatness, perpendicularity, symmetry, and circular run-out, the five characteristics of the old ISO 2768-2 K/H/L system, are not valid in the header. Surface profile replaces all five because it defines a tolerance zone of uniform width around the nominal integral surface, which contains any deviation the other five characteristics would have caught.

The tolerance zone that a surface profile specification defines is a 3D envelope around the CAD surface, not a 2D relationship between features. Straightness, flatness, and perpendicularity variations all fall inside or outside that envelope. The ⌓ frame in ISO 22081 does not carry additional modifiers like CZ or common zone unless the drafter adds them. Any specification element from ISO 5459 or ISO 1101 may be added on the general frame, provided it does not contradict the ISO 22081 rules.

5.3 How ISO 22081 identifies features of size (Rule H)

Rule H defines which features the general size specification applies to. The specification applies to a feature of size that meets three conditions: the size indication carries no individual tolerance, the size is not a theoretically exact dimension in a rectangular frame, and the size is not an auxiliary dimension in brackets. Rule H additionally allows the feature of size to be identified by a CAD attribute that defines the nominal value, not by a written dimension on the drawing. The 3D CAD model becomes a legally sufficient source of the nominal, provided the model is part of the technical product documentation.

This is the point at which ISO 22081 breaks with the 1989 approach. ISO 2768-1 assumes every dimension is written on a 2D drawing. ISO 22081 assumes the drawing may consist of a 3D CAD model plus a title-block annotation. For parts routed straight from a STEP file with a marked-up PDF, the CAD attribute path in Rule H is the mechanism that lets ISO 22081 govern parts that never had a fully dimensioned drawing. Design intent moves out of the paper drawing and into the model, which aligns with the [DFM design guidelines](/dfm-design-guidelines/) many shops now expect from CAD first customers.

6. What ISO 2768 does not cover, and what does

ISO 2768 does not govern threads, surface roughness, shaft-hole fits, or explicit geometric position. Each has its own standard. Applying ISO 2768 to features outside its scope produces parts that meet the general tolerance but fail their function.

Clause 1 of ISO 2768-1 lists three categories the standard does not apply to: linear and angular dimensions covered by reference to other standards, auxiliary dimensions in brackets, and theoretically exact dimensions in rectangular frames. In practice four categories account for almost every ambiguity a supplier raises after quoting.

Threads follow ISO 965-1 and ISO 965-2, with tapping drill sizes taken from Machinery’s Handbook where ISO does not publish them. A drawing that relies on ISO 2768-m for a tapped hole silently defaults to whatever tolerance the shop’s tap and drill combination happens to deliver. For the correct callout format, see metric thread chart.

Surface roughness follows ISO 21920-1, -2, and -3, which replaced ISO 4287, 4288, and 1302 in 2021. Two faces of very different roughness can be compliant with the same 2768 class, because the class says nothing about the surface texture the general dimensions are measured on. Roughness callouts belong on the feature, not in the header block.

Shaft-hole fits follow ISO 286. Individual fit callouts on a diameter override the general class for that specific feature. The general class alone cannot hit a slip fit, because its deviations are far wider than any IT7 band.

Explicit geometric position, profile, and orientation callouts on individual features are outside both ISO 2768 and ISO 22081’s general specifications. Any feature that needs true position, profile of a surface, or parallelism as a controlled characteristic must carry an individual feature control frame per ISO 1101 or ASME Y14.5, next to that feature.

7. The rejection clause most drawings ignore

Clause 6 of ISO 2768-1 says a feature that exceeds the general tolerance does not automatically fail. Rejection depends on whether the function is impaired. This clause decides who pays when a marginal part reaches inspection.

Every ISO 2768 article you find online lists the deviation tables. Almost none quote Clause 6, which changes how the tables work in practice. The original text reads: “Unless otherwise stated, workpieces exceeding the general tolerance shall not lead to automatic rejection provided that the ability of the workpiece to function is not impaired.” Annex A.4 restates the same rule as informative guidance. Both are part of ISO 2768-1:1989 and both remain in force in 2026.

The clause has three commercial consequences that any RFQ writer should understand before signing a purchase order that cites ISO 2768-m.

First consequence. A supplier who ships a batch with a 30 mm shaft measured at 30.35 mm, where the m class allows ±0.3 mm, has overshot the general tolerance by 0.05 mm. Under Clause 6 the buyer cannot reject on that measurement alone. Rejection requires evidence that the function is impaired, which means an assembly, fit, or performance failure the buyer can document.

Second consequence. The word “shall” in Clause 6 is normative. A buyer who wants automatic rejection on any general tolerance overshoot must add explicit language to the drawing or the purchase order stating that Clause 6 does not apply. Silence defaults to function based rejection.

Third consequence. The supplier still owes the ability to demonstrate that the workshop’s customary accuracy meets the class specified. Annex A.3 requires the workshop to measure its customary accuracy and accept only drawings whose general tolerance is equal to or greater than that accuracy. A shop that repeatedly overshoots the m class on a run is failing Annex A.3 even if no individual part gets rejected under Clause 6. For a full list of the standards and clauses that decide acceptance in a machined part contract, see tolerance standards reference.

Engineering note. In a dispute over a batch marginally outside the general tolerance, Clause 6 shifts the burden of proof from the supplier to the buyer. The supplier does not have to prove the part is functional. The buyer has to prove it is not. Purchase orders that quote ISO 2768-m without additional language accept this burden by default.

8. When and how to switch title blocks

Three drawing populations need different migration paths. New drawings step to Rung 2 now. Legacy drawings in production stay on Rung 1 until scheduled revision. Suppliers who only read `ISO 2768-mK` need requalification before you send a Rung 2 or higher drawing.

8.1 New drawings starting this quarter

Any drawing released for a new project in the third quarter of 2026 should ship at Rung 2 or higher. The wording General tolerances ISO 2768-m / General geometrical tolerances ISO 22081 costs nothing to add, keeps the linear tables every shop already uses, and stops citing a withdrawn document for geometrical defaults. Adding this second line to a title block template takes one CAD change and propagates to every future drawing from that template.

8.2 Legacy drawings still in production

Existing drawings sitting on Rung 1 stay on Rung 1 until a scheduled revision. A running production drawing that ships parts weekly is not a candidate for a title block migration on its own, because the supplier requalification cost exceeds the benefit. The exception is any drawing entering a full engineering change for another reason, where the migration cost drops to marginal because the revision cycle is already open. Any RFQ against a legacy drawing should note the drawing’s Rung status so pricing reflects the standards in use, which the [RFQ portal](/rfq/) handles when the drawing is uploaded.

8.3 Suppliers who still read only mK

A shop that has never opened ISO 22081 will not read a Rung 2 drawing correctly on Rule E datum locking. The failure mode is silent: the shop machines to whatever geometrical defaults it has always used, and the first inspection report reveals the gap. Before sending Rung 2 drawings to a supplier, confirm they hold ISO 22081 and can name Rule E and Rule F by number. Suppliers who cannot should either be requalified or receive drawings held at Rung 1 with individual GD&T on all critical geometry.

Frequently Asked Questions

Is ISO 2768 obsolete in 2026?

Not obsolete, partly superseded. ISO 2768-1:1989, the linear and angular part, is still published and remains current until ISO 2768 Edition 2 replaces it. Edition 2 reached stage 60.00 pre-publication on 2 June 2026 under ISO/TC 213. ISO 2768-2:1989, the geometrical part, was withdrawn and replaced by ISO 22081:2021 in the ISO 8015 GPS framework. A drawing that cites ISO 2768-mK in July 2026 has one current half and one superseded half. New drawings should add a second line citing ISO 22081 for geometrical defaults, or move to the full ISO 22081 wording shown in Figure 1 of that standard.

Can I still write ISO 2768-mK on a new drawing?

Yes, but only the m half references a current standard. The K half points at ISO 2768-2:1989, withdrawn in 2021 and replaced by ISO 22081. A shop reading ISO 2768-mK today interprets the K clauses against a document ISO no longer maintains. The drawing is not defective and will still be quoted, but any dispute over geometrical defaults runs against a withdrawn document. For new drawings, the split wording General tolerances ISO 2768-m / General geometrical tolerances ISO 22081 keeps every linear table unchanged and moves the geometrical half onto a standard the supplier can still consult.

Does ISO 22081 give me a numerical tolerance table?

No. ISO 22081 does not provide a fixed normative table of tolerance values. Clause 4.3 states that tolerance values can be single values chosen by the drafter or variable values keyed to feature size and distance to the datum system. Annex A shows one example of a variable value table for illustration and is informative, not normative. This is the biggest departure from ISO 2768-2, which supplied three classes with fixed deviations. Every ISO 22081 general specification carries a numerical value the drafter picks, written into the surface profile frame and the linear and angular lines. There is no H, K, or L default.

What happens if a feature falls outside the general tolerance?

Rejection is not automatic. Clause 6 of ISO 2768-1 states that a workpiece exceeding the general tolerance does not lead to automatic rejection unless the ability of the workpiece to function is impaired. Annex A.4 repeats the rule. In a supplier dispute, the burden of proof sits on the buyer to demonstrate that function is impaired, not on the supplier to demonstrate that dimensions are within the class. A purchase order that wants automatic rejection on any overshoot must add explicit language overriding Clause 6. Silence in the drawing and the PO defaults to function based rejection, which favours the supplier.

Do I need to reference ISO 8015 when I use ISO 22081?

Not explicitly, but the reference is already active in the background. ISO 22081 defines general geometrical and general size specifications according to ISO 8015:2011, Clause 5.12. The independency principle and the feature principle from ISO 8015 apply to every ISO 22081 specification. A drawing that cites ISO 22081 in the title block does not need a second citation to ISO 8015 for the general specification to work. If the drawing follows the envelope requirement on individual features, the Ⓔ modifier per ISO 14405-1 is written next to those features, not in the header.

Does ISO 2768 apply to plastics or 3D printing?

ISO 2768-1 Clause 1 states the standard applies to parts produced by metal removal or formed from sheet metal. Note 2 allows the tolerances to be suitable for materials other than metal, without extending the scope. In practice, plastic injection moulding, urethane casting, and additive manufacturing each have their own tolerance guidance because the process capabilities differ from subtractive machining. Applying ISO 2768-m to a fused deposition modelling part sets an expectation the process cannot hold at every feature size. For polymer and additive parts, the general class should be relaxed to c or specified with individual tolerances on functional dimensions.

Does ISO 2768 cover parallelism, position, or profile?

No. ISO 2768-2 covered only five geometrical characteristics: straightness, flatness, perpendicularity, symmetry, and circular run-out. Parallelism, cylindricity, concentricity, profile of a surface or line, and true position were never inside its scope. ISO 22081 replaces the five old characteristics with a single surface profile specification but does not extend the scope to position or profile as individual controls. Any feature that needs parallelism, true position, or profile of a surface as a controlled geometric characteristic must carry an individual feature control frame per ISO 1101 or ASME Y14.5, next to that feature.

How do European and North American drawings differ on general tolerances?

European drawings default to ISO 2768 with a title-block callout. North American drawings, particularly in aerospace and automotive, default to ASME Y14.5 with feature-level GD&T on every controlled dimension and no general tolerance class equivalent. A US shop reading a European drawing with ISO 2768-m will apply the tables correctly if it holds the standard, but may read Clause 6 differently, because ASME conventions expect explicit tolerance on every dimension. When sending drawings across the two conventions, confirm which standard the supplier holds and how they interpret untoleranced dimensions before quoting.

Related Resources

Related Capability: CNC Machining Capabilities. Standard tolerances, machinable materials, and lead times EPOC CRAFTER holds under `ISO 2768-m` by default and `ISO 2768-f` on request.

Related Article: How to Tolerance a CNC Drawing. The wider decision framework covering which features earn individual tolerances, which stay under the general class, and where GD&T becomes mandatory.

Related Article: ISO 286 Fits: H7, g6, Transition, and Interference for CNC Parts. Shaft-and-hole fit selection for the specific diameters ISO 2768 leaves outside its scope.

Related Article: Surface Roughness Chart for CNC Parts covers the Ra, Rz, and N-grade values each CNC process actually delivers as-machined, and the ISO 21920 maximum rule that accepts a single Ra callout the surface texture track ISO 2768 explicitly does not govern.

Related Article: Metric Thread Chart and Tapped Hole Callouts covers M1.6–M100 sizes, tap drill diameters, the Four-Depth Rule for blind holes, and 6H/6g limits per ISO 965-2:2024 the thread callout track ISO 2768 explicitly does not govern.

Related Standards Reference: Tolerance Standards Reference Library. Full index of the ISO and ASME standards EPOC CRAFTER machines to, including ISO 2768-1, ISO 22081, ISO 286, ISO 21920, and ISO 965.

Related Case Study: Case Commentary in Insights. Quality events and inspection reports showing how general and individual tolerance callouts interact in real production runs.