Manual of Engineering Drawing, : Technical Product Specification and Documentation to British and International Standards

318 Pages·2009·20.3 MB·English

by  Colin Simmons

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First edition by Arnold 1995
Reprinted by Butterworth Heinemann 2001, 2002
Second edition 2004
Reprinted 2004, 2005, 2006
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British Library Cataloguing in Publication Data
Simmons, C. H. (Colin H.)
Manual of engineering drawing : a guide to ISO and ASME standards. - 3rd ed.
1. Engineering drawings 2. Mechanical drawing - Standards
I. Title II. Maguire, D. E. (Dennis E.)
604.2
Library of Congress Cataloging-in-Publication Data
Library of Congress Catalog Number: 2008938627
ISBN–13: 978-0-7506-8985-4
Printed and bound in Great Britain
09 10 11 12 13 10 9 8 7 6 5 4 3 2 1
Preface
I received the request to prepare a third edition of Manual In line with ‘Standardization being a continuous proc-
of Engineering Drawing with mixed feelings. It was ess medium,’ this revision also includes the addition of
not that I did not want to do a revision, in fact I was the following four new comprehensive chapters:
keen to do so, being very conscious that some of the
contents was in need of updating to refl ect the latest ‘3 D Annotation’ which deals with the Digital Product
developments, made by the ever-changing world of Defi nition Data Practices, aligned to ISO 16792 Tech-
technology, and by ISO/BS Standardization, and I also nical Product Documentation: Management and pres-
saw it as an opportunity to enhance the book’s con- entation of digital product defi nition data and ASME
tent, by introducing new chapters on topical subject Y 14.41.
matters. But, I was aware that my dear friend and co-
author over the past thirty years would be unable to ‘The Duality Principle’ this being a Geometric Product
play a part in this revision by virtue of ill-health. specifi cation approach based on the concept that any
I discussed my dilemma with Neil Phelps, a practis- given workpiece exists in several different “worlds” or
ing mechanical design engineer and fellow colleague, as several different versions at the same time, as con-
on various ISO and British Standards committees, with sidered by the Designer and the Verifi cation Engineer.
whom I have worked closely for many years, and was It is the essential link between the Design Intent and
delighted when Neil expressed his desire and willing- the Verifi cation of the end product.
ness to assist in the revision and become a co-author.
I welcome Neil on board and feel assured that with ‘The Differences between the American ASME Y 14.5
his valued expertise, input and acumen this Manual M Geometric Dimensioning and Tolerancing (GD &
of Engineering Drawing will enjoy continued success T) and ISO/BS 8888 Geometric Dimensioning and
in the future, as it as proven to be over the past Tolerancing Standards’, the subtle differences of com-
decades. mon terms, and the effects of them being interpreted in
different ways are identifi ed and analysed …
This latest edition of the Manual of Engineering
Drawing has been revised to include and explain lat- ‘Surface Texture’ The Composition and Application
est developments in the fi elds of Technical Product of the Related Graphical Symbology
Specifi cation and Geometric Product Specifi cation, The mandatory positions for the indication of surface
in line with the latest published ISO, European, and texture requirements are illustrated and, explained in
British Standards, including BS 8888:2008–‘Technical line with BS/EN/ISO 1302 compliances.
Product Specifi cation’, which in 2000 replaced BS 308
‘Recommendations for Engineering Drawing Practice’. The text that follows covers the basic aspects of en-
gineering drawing practice required by college and
Included in the revised updates are: university students, and also professional drawing
The importance and advantages that may be obtained, offi ce personnel. Applications show how regularly
by having an effective Confi guration Management and used standards should be applied and interpreted.
Control, within a Management system, whether the
system be of a highly sophisticated CAD type or that Geometrical constructions are a necessary part of engi-
of a manual type. neering design and analysis and examples of two-and
Computing developments and the impacts on indus- three-dimensional geometry is provided. Practice is
try and commerce in relation to CAD Organization invaluable, not only as a mean of understanding prin-
and various applications. ciples, but in developing the ability to visualize shape
v
vi Preface
and form in three dimensions with a high degree of Please accept our apologies for continuing to use the
fl uency. It is sometimes forgotten that not only does term ‘draughtsmen’, which is the generally understood
a draughtsman produce original drawings but is also collective noun for drawing offi ce personnel, but
required to read and absorb the content of drawings he implies equality in status.
receives without ambiguity.
In conclusion, may we wish all readers every success
The section on engineering diagrams is included to in their studies and careers. We hope they will obtain
stimulate and broaden technological interest, further much satisfaction from employment in the absorbing
study, and be of value to students engaged on project activities related to creative design and considerable
work. Readers are invited to redraw a selection of the pleasure from the construction and presentation of
examples give for experience, also to appreciate the accurately defi ned engineering drawings incapable of
necessity for the insertion and meaning of every line. misinterpretation.
Colin Simmons
Acknowledgements
The authors express their special thanks to the British Barber and Colman Ltd
Standards Institution Chiswick High Road, London, Bauer Springs Ltd
W4 4AL for kind permission to reprint extracts from Delphi Diesel Systems
their publications. GKN Screws and Fasteners Ltd
Glacier Vandervell Ltd
We are also grateful to the International Organization GGB Bearing Technologies
for Standardization, Genève 20, Switzerland, for grant- F S Ratcliffe Ltd
ing us permission to use extracts from their publica- Salterfi x Ltd
tions.
Matthew Deans and his staff at Elsevier:
We very much appreciate the encouragement and Jonathan Simpson, Melanie Benson, and Lyndsey
friendly assistance given to us by:- Dixon.
Ford Motor Company Ltd To, Brian and Ray for sheet metal and machine shop
SKF (UK) Ltd examples, models.
KGB Micros Ltd
Norgren Martonair Ltd Our fi nal thanks go to Colin’s and Dennis’ patient
Loctite Holdings Ltd spouses for their understanding and encouragement
Staefa Control System Ltd since work was started in 1973 on the fi rst edition of
Autodesk Ltd Manual of Engineering Drawing.
vii
Chapter 1
Drawing office management and
organization
Everyarticleusedinourday-to-dayliveswillprobablyhave 5. Typesoflineandwriting
been produced as a result of solutions to a sequence of 6. Colouroflines
operationsandconsiderations,namely: 7. Dimensionfigures
8. Relativeimportanceofdimensions
1. Conception
9. Indicationofmaterialsondrawings
2. Designandanalysis
10. Variousdegreesoffinish
3. Manufacture
11. Screwthreads
4. Verification
12. Flatsandsquares
5. In-service(maintenance)
13. Tapers
6. Disposal.
14. Abbreviationsfordrawings.
The initial stage will commence when an original mar-
Therewerealsofivefiguresillustrating:
ketableideaisseentohaveapossiblecourseofdevelopment.
Theconceptwillprobablybeviewedfromanartisticanda 1. Methodofprojection
technologicalperspective. 2. Typesofline
Theappearanceandvisualaspectsofaproductarevery 3. Viewsandsections
importantincreatinganacceptablegoodfirstimpression. 4. Screwthreads
Thetechnologistfacestheproblemofproducingasound, 5. Tapers.
practical,safedesign,whichcomplieswiththeinitialspec-
First angle projection was used for the illustrations and
ificationandcanbeproducedataneconomicalcost.
thepublicationwasprintedonA5sheetsofpaper.
Duringeverystageofdevelopmenttherearemanyprog-
DuringtheearlydaysoftheIndustrialRevolutionmanu-
ress records to be maintained and kept up to date so that
facturerssimplycomparedandcopiedcomponentdimensions
referencetothecompletehistoryisavailabletoresponsible
to match those used on the prototype. However, with the
employeesandregulatorybodies.
introductionofquantityproductionwherecomponentswere
Formanyyearsvarioustypesofdrawings,sketchesand
requiredtobemadeatdifferentfactorysites,measurementby
paintingshavebeenusedtoconveyideasandinformation.In
moreprecisemeanswasessential.Individualmanufacturers
the last decade 3D models and rapid prototypes have also
developedtheirownstandardmethods.Clearly,forthebenefit
becomeacommonwayofconveyingdesignintent.Howev-
ofindustryingeneralaNationalStandardwasvital.Laterthe
er,agoodrecognizablepicturewilloftenremoveambiguity
morecomprehensiveBritishStandardofLimitsandFitswas
whendiscussingaprojectandassistinovercomingapossi-
introduced.Therearetwoclearaspects,whicharenecessary
blelanguagebarrier.
tobeconsideredinthespecificationofcomponentdrawings:
BritishStandardsarelistedintheBritishStandardsCat-
alogueandtheearliestrelevantEngineeringStandardsdate 1. Thedrawingshowsthedimensionsforthecomponentin
backto1903.Standardsweredevelopedtoestablishsuitable threeplanes.Dimensionsofthemanufactured
dimensions for a range of sizes of metal bars, sheets, nuts, componentneedtobeverifiedbecausesomevariationof
bolts, flanges, etc. following the Industrial Revolution and sizeineachofthethreeplanes(length,breadth,and
usedbytheEngineeringIndustry.ThefirstBritishStandard thickness)willbeunavoidable.Thedesigner’s
for Engineering Drawing Office Practice published in Sep- contributionistoprovideaCharacteristicsSpecification,
tember1927onlycontained14clausesasfollows: whichincurrentjargonisdefinedasthe‘DesignIntent
Measurand’.
1. Sizesofdrawingsandtracings,andwidthsoftracing
2. Themetrologistproducesa‘CharacteristicsEvaluation’
clothandpaper
whichissimplytheMeasuredValue.
2. Positionofdrawingnumber,dateandname
3. Indicationofscale The drawing office is generally regarded as the heart
4. Methodofprojection of any manufacturing organization. Products, components,
ManualofEngineeringDrawing
Copyright(cid:1)2009ElsevierLtd.Allrightsofreproductioninanyformreserved. 1
2 ManualofEngineeringDrawing
ideas, layouts, or schemes which may be presented by a (e) qualitycontrolandinspection;
designer in the form of rough freehand sketches, may be (f) updating,modification,andreissuingofdrawings.
developed stage by stage intoworking drawings and anno- 2. CompanystandardsManydrawingofficesusetheirown
tated3Dmodelsbythedraughtsman.Thereisgenerallyvery standardmethodswhicharisefromsatisfactorypast
littleconstructiveworkwhichcanbedonebyotherdepart- experienceofaparticularproductorprocess.Also,
mentswithinthefirmwithoutanapproveddrawingofsome particularstylesmayberetainedforeasyidentification,
formbeingavailable.Thedrawingistheuniversalmeansof e.g.,certainprestigecarscanberecognizedeasilysince
communication. someindividualdetails,inprinciple,arecommontoall
Drawings are made to an accepted standard, and in the models.
United Kingdom, it is BS 8888, containing normative and 3. StandardsfordimensioningInterchangeabilityand
informative references to international standards. These qualityarecontrolledbytheapplicationofpractical
standards are acknowledged and accepted throughout the limits,fitsandgeometricaltolerances.
world. 4. MaterialstandardsPhysicalandchemicalpropertiesand
Thecontentsofthedrawing(andannotated3Dmodels) non-destructivetestingmethodsmustbeborneinmind.
are themselves, where applicable, in agreement with sepa- Notemustalsobetakenofpreferredsizes,stocksizes,
rate standards relating to materials, dimensions, processes, andavailabilityofrod,bar,tube,plate,sheet,nuts,bolts,
etc. Larger organizations employ standards engineers who rivets,etc.,andotherbought-outitems.
ensurethatproductsconformtoBritishandalsointernation- 5. DraughtingstandardsandcodesofpracticeDrawings
alstandardswherenecessary.Gooddesignisoftentheprod- mustconformtoacceptedstandards,butcomponentsare
uctofteamworkwheredetailedconsiderationisgiventothe sometimesrequiredwhichinadditionmustconformto
aesthetic, economic, ergonomic and technical aspects of a certainlocalrequirementsorspecificregulations,for
given problem. It is therefore necessary to impose the ap- examplerelatingtosafetywhenoperatingincertain
propriatestandardsatthedesignstage,sinceallmanufactur- environmentsorconditions.Assembliesmayberequired
inginstructionsoriginatefromthispoint. tobeflameproof,gastight,waterproof,orresistantto
A perfect drawingcommunicates anexact requirement, corrosiveattack,anddetailedspecificationsfromtheuser
orspecification,whichcannotbemisinterpretedandwhich maybeapplicable.
mayformpartofalegalcontractbetweensupplieranduser. 6. Standardpartsaresometimesmanufacturedinquantity
Engineeringdrawingscanbeproducedtoagoodprofes- byacompany,andareusedinseveraldifferent
sionalstandardifthefollowingpointsareobserved: assemblies.Theuseofstandardpartsreducesan
unnecessaryvarietyofmaterialsandbasicallysimilar
a. thetypesoflinesusedmustbeofuniformthicknessand
components.
density;
7. StandardsforcostsThedraughtsmanisoftenrequiredto
b. eliminatefancyprinting,shadingandassociated
comparecostswheredifferentmethodsofmanufacture
artistry;
areavailable.Acomponentcouldpossiblybemadeby
c. includeonthedrawingonlytheinformationwhichis
forging,bycasting,orbyfabricatingandwelding,anda
requiredtoensureaccurateclearcommunication;
decisionastowhichmethodtousemustbemade.The
d. useonlystandardsymbolsandwherenoothermethodof
draughtsmanmustobviouslybewellawareofthe
specificationexist,appropriateabbreviations;
manufacturingfacilitiesandcapacityofferedbyhisown
e. ensurethatthedrawingiscorrectlydimensioned
company,thecostsinvolvedwhendifferenttechniquesof
(adequatelybutnotover-dimensioned)withno
productionareemployed,andalsoanideaofthelikely
unnecessarydetails.
costswhenworkissub-contractedtospecialist
Remember that care and consideration given to small manufacturers,sincethisalternativeoftenprovesan
details make a big contribution towards perfection, but economicproposition.
that perfection itself is no small thing. An accurate, well- 8. DatasheetsTablesofsizes,performancegraphs,and
delineatedengineeringdrawingcangivethedraughtsmana conversionchartsareofconsiderableassistancetothe
responsibleconsiderableprideandjobsatisfaction. designdraughtsman.
Thefieldofactivityofthedraughtsmanmayinvolvethe
Figure1.1showsthemainsourcesofworkflowingintoa
use,oranappreciation,ofthefollowingtopics.
typical industrial drawing office. The drawing office pro-
vides a service to each of these sources of supply, and the
1. CompanycommunicationsMostcompanieshavetheir
workinvolvedcanbeclassifiedasfollows.
ownsystemswhichhavebeendevelopedoveraperiodof
timeforthefollowing: 1. EngineeringTheengineeringdepartmentsareengaged
(a) internalpaperwork; in:
(b) numberingofdrawingsandcontracts; (a) currentproduction;
(c) codingofpartsandassemblies; (b) development;
(d) productionplanningforcomponentmanufacture; (c) research;
Chapter | 1 Drawingofficemanagementandorganization 3
Chief
Engineering draughtsman
Section
leaders
Drawing
Sales office Service
Technical
Designers
clerks s
g
n
wi
Senior Standards dra
draughtsmen section d
e
h
s
ni
Manufacturing Draughtsmen Checkers Fi
units
FIGURE 1.1 Trainees
(d) manufacturingtechniques,whichmayincludea
Drawing office library
studyofmetallurgy,heat-treatment,strengthof
materialsandmanufacturingprocesses;
Reprographic section
(e) advancedprojectplanning;
(f) fieldtestingofproducts.
2. SalesThisdepartmentcoversallaspectsofmarketing Manufacturing Sales Service Development
units
existingproductsandmarketresearchforfuture
products.Thedrawingofficemayreceiveworkin FIGURE 1.2
connectionwith:(a)generalarrangementandoutline
draughtsmenofvariousgrades.Whenworkiscompleted,the
drawingsforprospectivecustomers;(b)illustrations,
section leader then passes the drawings to the checking
chartsandgraphsfortechnicalpublications;(c)
section. The standards section scrutinizes the drawings to
modificationstoproductionunitstosuitcustomers’
ensurethattheappropriatestandardshavebeenincorporat-
particularrequirements;(d)applicationandinstallation
ed.Allschedules,equipmentlists,androutineclericalwork
diagrams;(e)feasibilityinvestigations.
arenormallyperformedbytechnicalclerks.Completedwork
3. ServiceTheservicedepartmentprovidesareliable,
for approval by the chief draughtsman is returned via the
promptandefficientafter-salesservicetothecustomer.
sectionleader.
Thedrawingofficereceivesworkassociatedwith(a)
Since drawings may be produced manually, or by elec-
maintenancetoolsandequipment;(b)servicekitsfor
tronic methods, suitable storage, retrieval and duplication
overhauls;(c)modificationstoproductionpartsresulting
arrangements are necessary. Systems in common use in-
fromfieldexperience;(d)servicemanuals.
clude:
4. ManufacturingunitsBriefly,thesecoveralldepartments
involvedinproducingthefinishedend-product.The (a) filingbyhandintocabinetstheoriginalmaster
drawingofficemustsupplycharts,drawings,schedules, drawings,innumericalorder,forindividualcomponents
etc.asfollows: orcontracts;
a. workingdrawingsofallthecompany’sproducts; (b) microfilmingandtheproductionofmicrofiche;
b. drawingsofjigsandfixturesassociatedwith (c) computerstorage.
manufacture;
Thepreservationandsecurityoforiginaldocumentsisof
c. plant-layoutandmaintenancedrawings;
paramountimportanceinindustry.Itisnotnormalpractice
d. modificationdrawingsrequiredtoaidproduction;
to permit originals to leave the drawing office. A drawing
e. reissueddrawingsforupdatedequipment;
maytakeadraughtsmanseveralweekstodevelopandcom-
f. drawingsresultingfromvalueanalysisandworks’
pleteandthereforehasconsiderablevalue.Thereprographic
suggestions.
staffwill distribute copies which are relativelyinexpensive
Figure 1.2 shows the organization in a typical drawing for further planning, production and other uses. A library
office. The function of the chief draughtsman is to take sectionwillmaintainandoperatewhateverarchivearrange-
overall control of the services provided by the office. The ments are in operation. A large amount of drawing office
chiefdraughtsmanreceivesallworkcomingintothedrawing workcomesfromcontinuousproductdevelopmentandmod-
office,whichheexaminesanddistributestotheappropriate ificationsoeasyaccesstopastdesignsandrapidinformation
sectionleader.Thesectionleaderisresponsibleforateamof retrievalisessential.
4 ManualofEngineeringDrawing
Engineering drawing practices Feedback
Thecommentssofarrefertodrawingofficesingeneraland
Company application.
typical organizational arrangements which are likely to be Design, manufactu-
foundwithintheengineeringindustry.Goodcommunication ring, sales and service
Implementation and
bytheuseofdrawingsofqualityreliesonensuringthatthey Company
Organization communication
computer strategy
conformtoestablishedstandards. and policy for 5 and methods systems for all
BS 5070, Parts 1, 3, and 4 dealing with engineering year term users
diagram drawing practice, is a companion standard to BS Hardware
8888 andcaters for the same industries;it providesrecom-
mendationsonawidevarietyofengineeringdiagrams.Com- Software
Performance
monly,asadiagramcanbecalleda‘drawing’andadrawing monitoring
Resources and control
can be called a ‘diagram’, it is useful to summarize the
differenceinthescopesofthesestandards.BS8888covers FIGURE 1.3 Generalcomputerpolicyrelationships.
what are commonly accepted to be drawings that define
shape, size and form. BS 5070 Parts 1, 3, and 4 covers
(a) CADmanagementroles;
diagrams that are normally associated with flow of some
(b) creation,trainingandmaintenanceofcapableCAD
sort, and which relate components (usually indicated by
operators;
symbols) functionally one to another by the use of lines,
(c) CADawarenessofdesignprojectteammembersin
butdonotdepicttheirshape,sizeorform;neithermaythey
additiontotheirleaders;
ingeneralindicateactualconnectionsorlocations.
(d) theflowofworkthroughthesystemandtheselectingof
Therefore, any drawing or diagram, whether produced
suitabletypesofproject;
manually or on computer aided draughting equipment,
(e) associateddocumentation;
must conform to established standards and will then be of
(f) possiblechangestoproductionmethods;
asatisfactoryqualityforcommercialunderstanding,useand
(g) needsinvolvingthecustomerandsub-contractor;
transmissionbyelectronicandmicrofilmingtechniques.All
(h) systemneedsrelatingtoplanning,securityand
of the examples which follow conform to the appropriate
upgrading;
standards.
(i) CADlibraryanddatabase(storageofdrawings,
symbols,etc.)andarchiveprocedures;
(j) Configurationmanagement.
Drawing practice and the computer
(CAD: Computer aided draughting Whenintroducingorreplacing aCADsystemitisvery
and design) importanttotaketimetoconsiderpoints(f)to(i)asthesecan
haveamajorimpactonthroughlifecosts.Ifyouaskyourself
The computer has made a far bigger impact on drawing thequestion‘In5,10,or15+yearstime,willIstillneedto
officepractices thanjustbeingabletomimicthetradition- maintaintheelectronicproductinformation’.Iftheansweris
al manual drawing board and tee square technique. How- ‘yesorpossibly’thenthefollowingneedscarefulconsider-
ever,itdependsondrawingofficerequirementsandifonly ation.
single, small, two dimensional drawings and sketches are Theneedtoconsiderpossibledownstreamapplications
occasionally required and storage of originals is not an such as Computer aided Machining (CAM), Inspection
issue, then a manual drawing system may still be appro- (CAI)andAnalysis,i.e., finiteelementanalysis(FEA)and
priate. CAD can however perform a much more effective compatibility with existing systems (or the requirement to
roleinthe designprocessandmanyexamples ofitsability replacethem)beingveryimportant.
follow – but it will not do the work on its own. The input Compatibility with potential customer and sub-
by the draughtsman needs to follow the same standards contractor systems should also be investigated because if
applied in the manual method and this fact is often not thisisacontrollingrequirementthenselectionofasuitable
understood by managers hoping to purchase CAD and system couldbelimited.
obtain immediate answers to design enquiries. The Longevity ofthe manufactured productswillalsoplaya
draughtsman needs the same technical appreciation as be- significantroleinsystemselection.Inmanyareasofindustry
fore plus additional computing skills to use the varied regulatoryorcontractrequirementsrequireretentionofdesign
software programs which can be purchased. recordsforaperiodoftimeaftertheproductiswithdrawnfrom
To introduce CAD, an organization must set out clear service. This period of time, when added to the length of
objectiveswhichareappropriatetotheirpresentandfuture servicecouldbeconsiderable,i.e.,inexcessof25years.As
requirements and Fig.1.3 includes aspectsof policywhich aresult,costsassociatedwithhardwareandsoftwareupgrades
could appear in such plans. The following need consider- andsystemmaintenanceneedtobeconsidered.Insomecases,
ation: thecostsassociatedwithupgradescanbeoffsetagainstnew
Chapter | 1 Drawingofficemanagementandorganization 5
products, but nevertheless, ongoing maintenance of legacy Managing Director
databasescanbecostly.Itisinterestingtonotethatthiswas
a problem that was often not foreseen in the early days of
CAD.Therushbyindustrytomovefromthedrawingboard Manufacturing Chief Finance CAD
Manager Engineer Manager Director
toCADhasinsomecases,ledtocompanieschangingCAD
systemsandstrugglingtomaintainlegacydrawingswithout
costly redraws. Even today, with some very good CAD file Chief
Draughtsman
translatorsonthemarket,100%datatransfercan’talwaysbe Applications Systems
Manager Manager
guaranteedwithoutsomeremedialwork.
Apossiblesolutionforconsiderationcouldbemaintain- FIGURE 1.4
ingthedrawingsofastableproductonmicrofilmorpossibly
an enduring electronic format such as Adobe Acrobat files
(.PDF). Some companies are already future proofing their A drawing standard
designinformationbyretainingdrawingsandmodelsintheir
From time immemorial, drawings have been the medium
nativeCAD format and also in .PDF format and on micro-
used to convey ideas and intentions. Hence the adage
film.
that ‘a picture is worth a thousand words’. No need for
Configurationcontrol isalsoequally importanttoCAD
language, the picture tells it all. In recent years there has,
systemsasitistomanualsystemsandextracareneedstobe
unfortunately, developed another opinion since CAD
takentoensureunauthorisedaccesstomasterfiles.
appearedonthescene,thatthereisnoneedforadraughts-
Many similar aspects will be appropriate in particular
mannowasthecomputerdoesitall.Thetruthofthematter
applicationsbutgoodintentionsarenotsufficient.Itisnec-
is that the computer is able to extend the range of work
essary to quantify objectives and provide dates, deadlines,
undertakenbythedraughtsmanandisreallyaverywilling
numbers, individual responsibilities and budgets which are
slave, the quality of the product produced from a drawing
achievableifpeoplearetobestretchedandgivenincentive
is solely down to the competence of the designer or
after fullconsultation.Presentlines ofcommunication will
draughtsman. The evolution of the Industrial Revolution
probably need to be modified to accommodate CAD, and
required the ‘pictures’ to be more detailed. In the pre-
planningintegrationisvital.Apossibleapproachhereisthe
mass-production era, manufacturewas based on ‘matched
appointmentofaCADDirectorwiththeultimateresponsi-
fits’, with the assistance of verbal communication.
bility for CAD technology assisted by a Systems Manager
The advent of mass production however, demanded more
andanApplicationsManager.
specific and precise specifications.
ACADDirectorhasthetaskofsettingandimplementing
Anationalformofdraughtingpresentationwasneededto
objectives and needs to be in a position to define binding
promote a common understanding of the objectives and in
policyanddirectfinancialresources.Hewillmonitorprog-
September1927,BS308cametofruition,astherecognized
ress.ASystemsManagerhastheroleofmanagingthecom-
NationalCodeofPracticeforEngineeringDrawing.
puter hardware, the software and the associated data.
The initial issue was A5-size and contained only 14
Company records and designs are its most valuable asset.
clauses. Dimensioning was covered in four paragraphs and
AllaspectsofsecurityaretheresponsibilityoftheSystems
tolerancing in only one. The recommendations were based
Manager.Securitydetailsaredealtwithinthenextchapter.
onjusttwoexampledrawings.Therecommendedprojection
The Applications Manager is responsible for day-to-day
wasfirstangle.
operationsontheCADsystemandthesteadyflowofwork
through the equipment. He will probably organize training
foroperatorsinthenecessarycomputerskills.Bothofthese
Revisions
managers need to liaise with the design project leaders to
provideandmaintainadraughtingfacilitywhichiscapable ThelifespanofBS308was73yearsandfiverevisionswere
ofincreasingproductivitytoaconsiderabledegree. made. The first in December 1943, followed by others in
Figure 1.4 shows the probable position of the CAD Di- 1953,1964,1972,and1985.The1972revisionwasamajor
rectorinthemanagementstructure.Hisdepartmentwillbe one, with the introduction of three separate parts replacing
providers of computer services to all other computer users thesingledocument:
withinthecompany. Thefifth(1985)revisionreplacedtheImperialstandard
withaMetricedition.
BS308wasfinallywithdrawnandreplacedbyBS8888
WhyintroduceBS8888andwithdrawBS308? in 2000. The revisions were necessary to keep abreast of
technologicalinnovations.
For73years,BS308wasahighlyregardeddrawingoffice As manufactured products became more sophisticated
practicedocument.Whythechangeandwhatwasbehindthe andcomplex,theprogressanddevelopmentofmanufactur-
decisiontowithdrawBS308andreplaceitwithBS8888? ingandverificationtechniquesaccelerated.Advancesinthe