7.5 Drawings Flashcards
Are engineering drawings drawn to size?
No
What type of paper are usually used for engineering drawings?
The A series (A4, A3, A2, A1, A0)
What is a pictorial view also known as?
Isometric
What is an isometric view?
A mathematical method of constructing a three dimensional object without using perspective. Makes drawings more realistic
When are break lines used in drawings?
When there is limited space on a piece of paper and to produce a more compact drawing
How are drilled holes portrayed in a drawing?
A thick lined circle
How are reamed holes presented in a drawing?
They will include an explanatory note differentiating them from plain holes
How are threaded holes defined in a drawing?
A thick circular line for the thread crest and a thin, broken line for the root
How is surface texture described in drawings?
Described through numbers, the smaller the number the smoother the finish
What standard lays down the conventions for engineering drawing?
decreed by ispec 2200 of the air transport association of America
What type of a view will show the a drawing and the angle of it truly?
Auxiliary view
What does a British standard (BS8888) lay down
Lays down the criteria and conventions which should be adhered to when creating an engineering drawing
What must be given in a drawing
Shape
Size/dimensions
Material specifications
Material finish
Relationship between the component and associated components in the assembly
What system do engineering drawings follow
iSpec 2 200
What does the title block provide
Every print must have identification. It’s provided by the title block
What is a zone
A combination of vertical and horizontal coordinates
What is a revision and what number system does it follow
It’s known as raising - in - issue and the drawing issue will raise by one digit (from issue 1 to issue 2)
On a drawing where is the revision block placed
It starts in the top right hand corner of each sheet and amendments are recorded on the left
What is the bill of materials and where is it
The list of all component parts on a drawing
above the title block
What does a continuous thickness line mean ___________
Visible outlines and edges
What does a continuously thin line mean
Imaginary lines of intersection, dimensions lines - basically just the imaginary lines
What does a continuously thin wiggly (irregular) line mean
Limits of partial or interrupted views or sections
What does a continuous thin straight line with zigzags mean
Limits of partial or interrupted views or sections
What does a dashed thick line mean - - - -
Hidden outlines and edges
What does a thin dashes straight line mean
Hidden outlines and edges
What does chain thin lines mean — - — - — -
Centre lines, lines of symmetry, pitch lines and circles
What does chain thin, thick at the ends and changes direction mean
Cutting planes
What does chain thick mean
Lines or surfaces to which a special requirement applies
Why do we use break lines
Due to the limited space on a sheet, so therefore we can produce smaller drawings
How are drilled holes portrayed
A thick lined circle
Diameter may be noted as well as depth if it is a blind hole
How do you show reamed holes
The reamed hole symbol with have a note differencing them from plain holes
How do you portray threaded holes
With a thick circular line for the thread crest and a thin broken line for the root
What is it meant by the surface texture
A measure of the smoothness of the surface finish
What does a smaller number mean in regards to surface texture
The smaller the number the smoother the surface is
In a drawing how would a designated surface texture be told to you
It is be stated as a number above the triangle
What is a perspective drawing
Shows a drawing in the way the human eye sees it - don’t accurately show dimensions
What is a sketch
A loosely structured hand drawing
What is the principle of first angle projection
Each view represents the side of the object remote from its adjacent view
What is the principle of third angle projection
Each view represents the side of the object nearest to it in adjacent view
What is a sectional view
Shows the object drawn as if it is removed so that the interior shape can be seen clearly
At what degree are sectional drawings drawn to the axis of the section
45 degrees
What does the auxiliary view show
The true shape of a surface is shown by auxiliary view drawn at right angles to the surface
What is an unilateral tolerance
One which permits a variation in one direction only, either above or below its basic size
What is the blueprint system used for
By the engineer to communicate his idea to various people who buy the raw material,plan manufacturing, build parts or buy the final part
What a detailed drawings or FAB
The detailing drawings of a single part
What does an assembly drawing depict
Show the relationship between two or more parts or a group of assemblies
What does an installation drawing show
Designed to describe exactly where certain parts, fixture etc are permanently affixed
What is an exploded- view drawing
Show every part that is in the assembly
often IPL make use of these
What does a schematic drawing show
Doesn’t show the exact image of the part but shows the principle of the operation
Ideal for trouble shooting
(Shows where objects are located in relation to each other - which way fluid would flow)
What do electrical wiring diagrams illustrate
Indicate size of wire, type of terminals - used to illustrate the principle
What ratio were aircraft drawings drawn at and why was this inconvenient
1:1
Because it meant that the cabinets had to be large enough to store them
What ways did people try and improve the storage of aircraft drawings
Aperture cards (Photographing them - mounted onto a card)
Microfilm
CD- ROMS
CDs
DVDs - preferred option
What does CAD stand for
Computer aided design
What did CAD do for the engineering world
It meant that everything could be designed electronically and could be stored on electronically too.
