GE Transportation
3.May.2012 General Tolerance Specification Rev. D
1. SCOPE
This specification defines the general tolerances in the Imperial and Metric systems to be used on GE
Transportation parts and products. For cast and forged parts, see the 84A226035AB.
Unless otherwise explicitly specified on a drawing for a particular dimension or characteristic, or in
the title block of this drawing (only for legacy drawings), these general tolerances shall be applied to
all new drawings created after the revision A issue date of this specification. It shall also apply to all
drawings that are formally reissued after the revision A issue date of this specification.
Where the primary dimensions on the drawing are Imperial, the Imperial tolerances in this document
shall apply. Where the primary dimensions on the drawing are Metric, the Metric tolerances in this
document shall apply.
1.1. ORDER OF PRECEDENCE
The following order of precedence define how tolerances shall be applied:
1.1.1.1. Explicit Tolerances – any tolerances on the drawing face take precedence over any of
document or instruction invoked.
1.1.1.2. Industry Standards – Items such as sheet metal thickness, which are driven by other
industry standards (such as ASME or ASTM) specified on the drawing face.
1.1.1.3. Implicit Tolerances – any characteristics on the drawing face that do not carry explicit
tolerances shall derive their tolerances from this document. This excludes items such as
thickness, thread creation, etc which shall be driven from other specifications (ANSI,
ASA, etc) which regulate these features.
1.1.1.4. GE Standards – Any internal GE standard invoked on the drawing face (such as the
84A208000 Wiring Standard).
1.1.1.5. Under-defined - Any characteristics without a tolerance from any of the previous points
shall be considered under-defined and GET Engineering consultation shall be sought.
2. ABBREVIATIONS, DEFINITIONS, and REFERENCES
Abbreviations
GD&T Geometric Dimensioning and Tolerancing
GET GE Transportation
For additional tolerance and geometric control definitions and standards, please refer to the
84A222563AD, 84A222563AG and 84A222563AP.
Drafting Standards per the 84A222563 series of documents, which are based on the ASME Y14.5 –
1994 and ASME Y14.100 – 2004.
3. CONFIGURATION CONTROL and REVISION HISTORY
For changes to this specification or review cycle, please consult the Standard Work Practice labeled
as General Tolerance Practices.
Author: Engineering Approval: PE Roundtable 84A226035
Issued: GET Engineering BUS. AREA: All DIST: On-Line Sheet 1 of 6
This Drawing is the Property of GENERAL ELECTRIC COMPANY. This drawing is loaned upon the express condition that it shall not be
reproduced in any manner, and shall be returned upon demand. It is submitted for evaluation purposes and it, and the information contained
therein, shall not be otherwise used nor disclosed to third parties without written permission of General Electric Co.
GE Transportation
3.May.2012 General Tolerance Specification Rev. D
The content of this specification shall be formally reviewed within 1 year after the most recent
revision.
Table 3a – Revision History
Revision Release Date Author Summary
0 18.Dec.2009 FS Bekeny Initial release
A 12.Dec.2010 M McCullough Document rewritten to conform with ASME Y14.5M
1994
B 16.Dec.2010 M McCullough Update Torque Requirements
C 19.Apr.2010 Add mfging best practices, clarify undercuts / burrs
D 3.May.2012 Clarify section 7
4. TOLERANCES FOR DIMENSIONAL CHARACTERISTICS
Dimensional characteristics are defined to include but not limited to:
• External linear dimensions
• Internal linear dimensions
• Diameters and radii of holes
• Radii (internal and external)
• Distances
• Chamfers
Table 4a – Tolerances for Dimensional Characteristics (Units in millimeters)
Tolerance class Tolerances for Nominal Dimension within Listed Range
over over over over over over over
Designation Description 0.50 3 6 30 120 400 1000 2000
up to up to up to up to up to up to up to up to
3 6 30 120 400 1000 2000 4000
f fine ±0.05 ±0.05 ±0.10 ±0.15 ±0.20 ±0.30 ±0.50 -
m medium ±0.10 ±0.10 ±0.20 ±0.30 ±0.50 ±0.80 ±1.20 ±2
c coarse ±0.20 ±0.30 ±0.50 ±0.80 ±1.20 ±2 ±3 ±4
vc very coarse - ±0.50 ±1 ±1.50 ±2.50 ±4 ±6 ±8
Table 4b – Tolerances for Dimensional Characteristics (Units in inches)
Tolerance class Tolerances for Nominal Dimension within Listed Range
over over over over over over over
Designation Description .02 .12 .25 1.0 5.0 15.0 40.0 80.0
up to up to up to up to up to up to up to up to
.12 .25 1.0 5.0 15.0 40.0 80.0 160.0
f fine ±.002 ±.002 ±.004 ±.006 ±.008 ±.012 ±.020 -
m medium ±.004 ±.004 ±.008 ±.012 ±.020 ±.032 ±.050 ±.080
c coarse ±.008 ±.012 ±.020 ±.032 ±.050 ±.080 ±.120 ±.160
vc very coarse - ±.020 ±.040 ±.060 ±.100 ±.160 ±.250 ±.320
Note that for values less than 0.50 millimeters or 0.02 inches; explicit tolerances on the drawing face are required.
Author: Engineering Approval: PE Roundtable 84A226035
Issued: GET Engineering BUS. AREA: All DIST: On-Line Sheet 2 of 6
This Drawing is the Property of GENERAL ELECTRIC COMPANY. This drawing is loaned upon the express condition that it shall not be
reproduced in any manner, and shall be returned upon demand. It is submitted for evaluation purposes and it, and the information contained
therein, shall not be otherwise used nor disclosed to third parties without written permission of General Electric Co.
GE Transportation
3.May.2012 General Tolerance Specification Rev. D
While no reference to the document shall be made, the values used in Table 4a align with the ISO 2768-1
(as released in 2009). The values used in Table 4b are the Imperial equivalent to Table 4a.
The default for all drawings shall be the Medium designation unless another is desired by Engineering.
To invoke another classification, simply change the callout on the drawing from a –m to the desired
designation. To restate, if the Default Tolerance on the drawing face reads “84A226035” and does not
carry a designation then that shall be considered 84A226035-m.
Recommendations:
• Fine - No known application at GET to date.
• Medium - Machined components.
• Coarse - Assemblies of moving parts.
• Very Coarse - Sheet metal, pipe, non-critical assemblies.
For cast and forged parts, see the 84A226035AB.
When a new drawing is created, the following shall be the default tolerance class applied unless
otherwise specified by engineering.
Defaults by business:
• Locomotive – vc
• Control – vc
• Off Highway (OHV) – vc
• Energy Storage – vc
• Locomotive Engine & Generator Sets – m
• Marine Engine – m
• Wind – m
• Propulsion – c
5. ANGULAR DIMENSION TOLERANCES
All angles shall be +/- 1°.
6. SURFACE TEXTURE TOLERANCES
There are no general tolerances for surface texture. Surface texture tolerances, when required, shall
be explicitly documented on the drawing in accordance with the ASME Y14.36 - 1996.
Surface textures are typically documented as follows:
xxx
For Metric xxx is the micrometer measurement. The default maximum finish value is 6.3.
Author: Engineering Approval: PE Roundtable 84A226035
Issued: GET Engineering BUS. AREA: All DIST: On-Line Sheet 3 of 6
This Drawing is the Property of GENERAL ELECTRIC COMPANY. This drawing is loaned upon the express condition that it shall not be
reproduced in any manner, and shall be returned upon demand. It is submitted for evaluation purposes and it, and the information contained
therein, shall not be otherwise used nor disclosed to third parties without written permission of General Electric Co.
GE Transportation
3.May.2012 General Tolerance Specification Rev. D
For Imperial xxx is the microinch measurement. The default maximum finish value is 250.
As for tolerancing, this finish value shall be considered a maximum value. In that if a finish of 125
micro-inches is specified then the roughest the part may be is 125 microinches but it could be
smoother. Where it is desired to strictly limit the range, this shall be explicitly listed on the drawing.
The following table provides a correspondence between metric arithmetical mean deviation (Ra), its
Imperial equivalent, and the roughness grade number. These are not direct conversions but rather
should be used as similar to. 50µm is similar to 2,000 µin which is also similar to N12.
Table 6a – Correspondence of Arithmetical Mean Deviation Ra and Roughness Grade Numbers
Roughness Values Ra
Roughness Grade Numbers
micrometers microinches
50 2000 N12
25 1000 N11
12.5 500 N10
6.3 250 N9
3.2 125 N8
1.6 63 N7
0.8 32 N6
0.4 16 N5
0.2 8 N4
0.1 4 N3
0.05 2 N2
0.025 1 N1
Author: Engineering Approval: PE Roundtable 84A226035
Issued: GET Engineering BUS. AREA: All DIST: On-Line Sheet 4 of 6
This Drawing is the Property of GENERAL ELECTRIC COMPANY. This drawing is loaned upon the express condition that it shall not be
reproduced in any manner, and shall be returned upon demand. It is submitted for evaluation purposes and it, and the information contained
therein, shall not be otherwise used nor disclosed to third parties without written permission of General Electric Co.
GE Transportation
3.May.2012 General Tolerance Specification Rev. D
7. CORNERS, BURRS, UNDERCUTS
ITEM DRAFTING AND MANUFACTURING PRACTICE
(A) Chamfer tolerances should be specified on the drawing face or per 84A226035.
Chamfer
(B) Unless otherwise Diameter Chamfer
Break Corner stated on the drawing, Up to 1" (25.4mm) 0.005 to 0.02 (0.127mm – 0.508mm)
break all corners on Over 1" to 2" (25.4mm – 0.005 to 0.04 (0.127mm – 1.016mm)
machined diameters or 50.8mm) 0.005 to 0.06 (0.127 – 1.524mm)
faces with a chamfer or Over 2" (50.8mm)
radius.
(C) Must be stated on drawing as "Sharp Corner" and have a maximum radius of 0.005 (0.127mm).
Sharp Corner
Radius Corner - (R) Specify on drawings only when a chamfer is not acceptable. Unless otherwise specified, radii of
or Fillet - (F) corners to be:
no radii specified -- See "B"
radii - specify on drawing = ± .02 (0.508mm)
(H) Specified per 84A226035.
Under-cut
(K) End projections on part-off cuts must be removed unless otherwise specified.
Part off
Thread Undercut Undercut diameter must be shown when thread is carried up to head undercut.
8. TORQUE
Torque tolerance shall be +/- 5% from the nominal value specified on the drawing. Where a torque
specification is used, that document shall take precedence over this one and +/- 5% shall only apply
where that document does not cover the full engineering definition.
Any torqueing requirements not specified on the drawing shall be considered under-defined.
9. MANUFACTURING BEST PRACTICES
9.1. GENERAL PRACTICES
Author: Engineering Approval: PE Roundtable 84A226035
Issued: GET Engineering BUS. AREA: All DIST: On-Line Sheet 5 of 6
This Drawing is the Property of GENERAL ELECTRIC COMPANY. This drawing is loaned upon the express condition that it shall not be
reproduced in any manner, and shall be returned upon demand. It is submitted for evaluation purposes and it, and the information contained
therein, shall not be otherwise used nor disclosed to third parties without written permission of General Electric Co.
GE Transportation
3.May.2012 General Tolerance Specification Rev. D
All applicable manufacturing best practices shall be used unless prohibitive or otherwise specified
on the drawing. Manufacturing best practices can be found in the 84A226035AC.
9.2. WIRING
Wiring best practices can be found in the 84A208000. Any drawing detailing wiring design / routing
shall follow this document.
10. APPLIED PRACTICES AND STANDING INSTRUCTIONS
While these documents shall not be used on the drawing face any longer as default tolerances, they
can be used to derive what the tolerance was / should be if the values in this document are not
acceptable for a particular feature or part – they are reference only. In that instance, it is
recommended to derive what the tolerance would be based on the applied practice and then explicitly
define that value on the drawing face. A list of known documents is shown here. Note that the
standards listed were the most commonly used; this is not an exhaustive list.
Business
Standard Number Description
Locomotive Engine Control Propulsion Wind OHV M&S Genset
41A282000 x General Assembly
84A208000 x x x Wiring
41A213278 x x General Assembly
41A213279 x x Casting Tolerances
41A213280 x x Machining Tolerances
SI-10359 x x Standard that covers all manufacturing
SI-10350 x x Bus Bar Insulation
SI-10559 x x List of processes for Finishes and Coatings
SI-10025 x Standard that covers all manufacturing
SI-10348 x Wiring & assemblies
SI-10027 x Bolt Torque
C50E76 x Material Testing
C50E82 x x Material Testing
K4015012 x x Knurling
ISO 2768-1-m x x General Machining Tolerances
ISO 2768-2-K x x General Machining Tolerances
ISO 4287 x x Theoretical Surface Texture Definitions
ISO 4288 x x Theoretical Surface Texture Definitions
ISO 13715 x x Edges of Undefined Shape
ISO 286-1 x x Interpreting Dimensions
ISO 286-2 x x Interpreting Dimensions
499A981AA x Pipe Bending Design Guidelines Bldg 10
84A216320 x Light Fabircation Guidelines
84A216320AB x Heavy fabrication Guidelines
B30E501 x
B30E5 x Mat'l Comp, Dimensions & Tolerances
B50E147A x Tubing
B50E147 x Tubing Dimensions & Tolerances
84D740043AC x Various Torques (GEVO)
K5903487 x x Tap Depth
84A224379 x x Critical Fasteners
M9946126 x Tap Drill Sizes
41C633023 x Counterbore and Spotfacing
84A225834-mK x ISO 2768-mK
84D740043 x x Various Torques (Generic)
84D740043AB x x Various Torques (????)
SI-10013 x Gear Casing
SI-10017 x Painting Machined Assemblies
SI-10011 x Mounting Pinions
SI-10008 x Motor Frame Parts
C50E90 x x Crankshaft Specification
C50E73 x x Steel Castings
Author: Engineering Approval: PE Roundtable 84A226035
Issued: GET Engineering BUS. AREA: All DIST: On-Line Sheet 6 of 6
This Drawing is the Property of GENERAL ELECTRIC COMPANY. This drawing is loaned upon the express condition that it shall not be
reproduced in any manner, and shall be returned upon demand. It is submitted for evaluation purposes and it, and the information contained
therein, shall not be otherwise used nor disclosed to third parties without written permission of General Electric Co.
