Who are the two organisations responsible for drawings standards?
British Standards Institution (BSI)
International Organization for Standardization (ISO)
Give the benefits of engineering drawings
- Conveys information between different people
- Standardised, intepreted the same way
- Shares information with people who don’t speak same language
Describe freehand sketching
Drawn without measurements
Often used to presents concept ideas
Give the benefits of freehand sketching
- Can be produced everywhere
- Minimal equipment needed
- Quickly illustrates information
- Improves communication between technical and non-technical people
Describe orthographic projection
The projection of a single view of a 3D object onto a drawing surface
Give the difference between first angle projection and third angle projection
First angle - model view is drawn opposite the face being viewed
Third angle - model view is drawn adjacent to the face being viewed
Describe isometric drawings
2D drawings with 3D views
Drawn at 30 degree angles
Describe section views
A view of a drawing of internal or external features of an object
Describe cross-sectional views
A sliced portion of an object to show hidden components
Describe detail views
Views that capture features of interest and display them in a view with greater scale
Describe assembly drawings
Illustrations used to explain how components fit together to create a product
List some features used in an assembly drawing
- Overall dimensions used ONLY
- Max/mini tolerances included
- Internal assemblies displayed in sectional views
- Leader lines w/ arrows/circles indicate external/internal parts
- Parts list including item numbers, description, quantity, material etc
Describe exploded view drawings
Components slightly seperated to show relationship or order of assembly for an item
What are some key points used in exploded view drawings?
Guide lines to show how parts line with each other
What is the national standard for engineering drawings?
BS 8888
All engineering drawings contain a title block, what information should be included in it?
- Title
- Name
- Checked
- Version
- Date
- Notes
- Scale
- Company name
- Projection
What is pitch circle diameter (PCD)?
Diameter of a circular component that is to be manufactured
List common abbreviations used in engineering drawings
AF, CL, CRS, CHAM, CBORE, CSK, EXT, INT
AF - across flats
CL - centre line
CRS - centres
CHAM - chamfer
CBORE - counterbore
CSK - countersink
EXT - external
INT - internal
List common abbreviations used in engineering drawings
NTS, Rev, SPEC, SFACE, THK, STD
NTS - not to scale
Rev - revision
SPEC - specification
SFACE - spot face
THK - thickness
STD - standard
What is the difference between lead and pitch in terms of screws?
Lead is the distance along screw’x axis, covered by one complete rotation
Pitch is the distance from the crest of one thread to the other
Define CAD
Computer aided design
What can CAD software do?
- Increase productivity
- Improve quality of design
- Improves communication
- Protect products when used in patent applications
- Create data bases
Give the benefits of CAD drawings
- Quicker, more accurate and easier to modify, share and produce
- Virtual testing can be carried out on 3D models
Give the benefits of hand-drawn drawings
- Can be produced anywhere
- Doesn’t rely on technology
- Cheap as no kit is required
