Download - Weld Symbol BS en Standards
StandardsThe British Standard for weld symbols is BS EN 22553. When identification of the weld process is required as part of the weld symbol the relevant weld process code is listed in BS EN ISO 4063.
Basic Weld SymbolThe weld symbol always includes
1. An arrow line
2. A reference line
3. A dashed line
4. A symbol
Note: Weld symbols on the full reference line relates to welds on the near side of the plate being welded. Weld symbols on the dashed line relates to weld on the far side of the plate. If the welds are symmetrical on both sides of the plate the dashed line is omitted. If the dashed line is above the full line then the symbol for the nearside weld is drawn below the reference line and the symbol for the farside weld is above the dashed line. For example see sketch below Supplemetary symbols below.
More Detailed Symbolic Representation of Weld
Welding.....Weld process numbers.
Table of Weld Symbols
SupplementarySymbolsThe weld symbols below are used in addition to the primary weld symbols as shown above. They are not used on their own.
Below is an example of the application of one of these symbol illustrating the identification of the location of the weld relative to the symbol.
Complementary Indication
Dimensioning Welds
Dimensioning
Linear Dimensioning
Note: A dimension which is not to scale is shown underlined
Angular Dimensioning
Chain-Parallel dimensioning
Examples of chain and parallel dimensioning are shwon above. The advantage of parallel dimensioning is that there is no build-up of tolerances.
Dimensioning a brokent feature.
Dimensioning Diameters
Dimensions of diameters are shown on view providing greatest clarity
Dimensioning Holes
Dimensioning Chamfers/Countersinks
Metric Screw Threads
Thread Designation
The complete designation of a screw thread gives
the thread symbol e.g. M for Metric
the thread size e.g. 6
the thread pitch e.g. x 1
the tolerance class e.g. 6H(Female) 6g (male)
the length of thread if not dimensioned separately eg. x 30 LNG
Notes:If the thread is standard course then the pitch need not be shown. However it is better that it is always shownIf the tolerance grade for the pitch diameter and the major diameter is the same then only one needs to be shown.Threads right handed (clockwise turn to screw in) unless a -LH suffix is added to indicate left hand thread.
The Class of Fit is a measure of the degree of fit between mating internal and external threads.
Classes of Fit
Three main Classes of Fit are defined for metric screw threads :
FINE: This has a tolerance class of 5H for internal threads and 4h for external threads.
MEDIUM: This has a tolerance class of 6H for internal threads and 6g for external threads.
COARSE: This has a tolerance class of 7H for internal threads and 8g for external threads.
If one class is shown for a male thread i.e 6g then the tolerance applies to the pitch dia and the major diameter.A dual tolerance is shown (5h6g) when a different tolerance is applied to the Pitch dia (5h) and the major dia (6h). The same principle applies to the female thread e.g. a tolerance grade (6H ) applies to both pitch dia and the minor dia. A tolerance grade (6H7H) refers to 6H for the pitch dia and 7H for the minor dia.
The typical designation for a thread on a drawing is as follows
M8 - 6e..This is a M8 course male thread with a 6e external(male) tolerance (before coating)
M8 x 1 - 6e.. This is a M8 course male fine thread with a 6e external(male) tolerance (before coating)
M8 - 6H... This is a M8 course female thread with a 6H internal(female) tolerance (not coated)
M8 - 6H - LH This is a Left hand M8 course female thread with a 6H internal(female) tolerance (not coated)
Pipe Threads
The typical designation for a Pipe Threads
R 1/2 External Taper - Sealing on Thread (BS 21)
Rc 1/2 Internal Tape - Sealing on Thread(BS 21)
Rp 1/2 Internal Parallel- Sealing on Thread (BS 21)
G 1/2 A,B or ext External Parallel - Not Sealing on Threads -Additional seal required(BS2779)
G 1/2(F = full thread) Internal Parallel Not Sealing on Threads -Additional seal required (BS2779)
TermAbbreviation or Symbol
Across FlatsAF
AssemblyASSY
CentresCRS
Centre Line ..On View
Centre line ..On NoteCL
Centre Of GravityCG
Chamfer of Chamferred..In a NoteCHAM
Cheese HeadCH HD
Countersunk/ CountersinkCSK
Countersunk HeadCSK HD
CounterboreCBORE
Cylinder or CylindericalCYL
Diameter..in a noteDIA
Diameter..preceding a dimension
DrawingDRG
Equally SpacedEQUI SP
ExternalEXT
FigureFIG
Full Indicated MovementFIM
HexagonHEX
Hexagon HeadHEX HD
Insulated or InsulationINSUL
InternalINT
Least Material Condition..In a NoteLMC
Least Material Condition..(Geom.Dim)
Left handLH
LongLG
MachineMC
MaterialMAT
MaximumMAX
Maximum Material Condition..In a noteMMC
Maximum Material Condition..(Geom. tol)
MinimumMIN
Not to Scale (In a note and underlinedNTS
NumberNO.
Pattern NumberPATT NO.
Pitch Circle DiameterPCD
Radius..In a noteRAD
Radius..Preceding a dimensionR
ReferenceREF
RequiredREQD
Right handRH
Round HeadRD HD
Screw of ScrewedSCR
Sheet (Drawing Number) SH
Sketch (prefix to Drawing Number) SK
SpecificationSPEC
Spherical Radius..Preceding dim SR
SpotfaceSFACE
Square ..In a noteSQ
Square ..Preceding dim
StandardSTD
Taper.. On Dia or Width
ThreadTHD
ThickTHK
ToleranceTOL
Typically OR TypicalTYP
UndercutUCUT
VolumeVOL
General Notes
Fabrication Notes
Machining Notes
Fastener Notes