Engineering drawings

Question 1

What are the specific information and requirements provided by engineering drawings?

Answer 1

Dimensions, Geometry, Tolerances, Material type, Finish, Hardware

Engineering drawings contain more detailed specifications compared to 3D models.

Question 2

How do 3D models differ from engineering drawings?

Answer 2

3D models are visual representations but do not contain all the information that drawings do.

Engineering drawings provide specific details like dimensions and tolerances.

Question 3

What tools were traditionally used for hand-drawn engineering drawings?

Answer 3

Pencils, pens, compasses, protractors, triangles

These tools were common for drafters working at drawing boards.

Question 4

What benefits do computer drawings provide over hand drawings?

Answer 4

Better quality, Higher accuracy, Easily saved and shared, Quick modifications

Computer drawings enhance design processes and manufacturing efficiency.

Question 5

What are engineering drawings?

Answer 5

Detailed diagrams showing all the details and specifications required to produce an engineering product

They illustrate size, shape, materials, and other information needed to create an object.

Question 6

Fill in the blank: Engineering drawings are not simply an image, but are used to illustrate the _______.

Answer 6

size, shape, materials, and any other information needed to create the object

This highlights the comprehensive nature of engineering drawings.

Question 8

Who is BS 8888 for?

Answer 8

Engineering designers and design engineers in the UK, sectors like mechanical, defence aerospace, automotive, rail, nuclear, independent design consultancies or design agencies handling design and drawing activities, users of the former national standard BS 308.

Question 9

What are British Standards?

Answer 9

National standards produced by the BSI group known as the British Standards Institution, in line with international standards from the International Organisation for Standardization (ISO).

Question 10

What is the purpose of BS 8888?

Answer 10

Unite all the ISO standards applicable to technical specification, give an index of ISO standards involved with different principles of technical product specification, provide BSI with a platform for further explanatory commentary where necessary.

Question 11

How is BS 8888 applied to engineering drawings?

Answer 11

It applies to both 2D drawings and 3D CAD models, formalises requirements for drawing borders and title blocks, and uses a comma as a decimal place instead of a full stop.

Question 12

What led to the need for international standards?

Answer 12

The globalisation of companies interacting across borders, necessitating standards to regulate drawings for universal understanding.

Question 13

What does the acronym ISO stand for?

Answer 13

International Organization for Standardization.

Question 14

What are the benefits of British Standards in drawings?

Answer 14

• Efficiency and effectiveness
• Fewer errors

Question 15

True or False: BS 8888 is only applicable to 2D drawings.

Answer 15

False.

Question 16

What role did the BSI Group play in relation to international standards?

Answer 16

Vital role in the development of the international standard on technical specification in connection with ISO.

Question 17

What results from working to a standard in engineering drawings?

Answer 17

Fewer supplier problems, more accurate parts and components, and fewer errors.

Question 18

What happens if all engineers adopt their own way of producing drawings?

Answer 18

Other engineers may struggle to interpret the drawings correctly, leading to mistakes or slower progress.

Question 19

What is tolerance in manufacturing?

Answer 19

Tolerance is the acceptable range of difference in measurements that is agreed upon for products.

Question 20

How many main types of lines are used in engineering drawings?

Answer 20

There are 5 main types of lines.

Question 21

What is a visible line in engineering drawings?

Answer 21

A thick dark line used to show the outline of an object’s visible edge or surface.

Question 22

Describe a hidden line.

Answer 22

A line made up of short dashes, representing features not visible from the direction of view.

Question 23

What is the purpose of centre lines in engineering drawings?

Answer 23

To indicate the centre of circles, holes, fillets, or circular/curved edges.

Question 24

How should centre lines be represented?

Answer 24

By a series of alternating short and long dashes that extend beyond the edges of the drawing.

Question 25

What are construction lines?

Answer 25

Light and thin lines used to construct layout work on an engineering drawing sheet.

Question 26

What are dimension lines?

Answer 26

Lines drawn with arrows on either side between two extension lines, indicating measurements.

Question 27

What is the purpose of extension lines?

Answer 27

They are parallel lines that extend out from two points of the drawing with a small gap where they meet the drawing.

Question 28

What symbol is used to record the tolerance of parts of a product?

Answer 28

The plus or minus symbol.

Question 29

Why is tolerance important for safety and quality?

Answer 29

Incorrect sizes could lead to accidents, and poor fit would lead to customer complaints.

Question 30

What is general tolerance?

Answer 30

Slight variation in size when making components, allowing for cheaper production.

Question 31

What is specific tolerance?

Answer 31

Used for specific parts where size is critical for safety, fit, accuracy, and functionality.

Question 32

What does a smaller tolerance typically allow for in production?

Answer 32

Cheaper production while ensuring products work and are safe.

Question 33

What a is title block?

Answer 33

A title block on a drawing is usually located in the bottom right-hand corner and contains all the information necessary to identify the drawing.

Question 34

Content of a Title Block 

Answer 34

Drawing reference number in drawing as per sequence along with reference to others Signatures and approval stamps and dates to revisions Author Drawing number Date Title Materials Scale  Sheet number  System of measurement  Projection

Question 35

What is scale?

Answer 35

The scales in engineering drawings are the ratio of the linear dimension of an object as presented in the original drawing to the actual linear dimensions of the same object itself. 

Question 36

What is first Angle Projection 

Answer 36

It is commonly used in Europe and most of the world.  However, as most CAD packages are produced in the United States, it is not uncommon to also see third angle being used in CAD drawings. When drawing in first angle the top view is placed below the front view and the right side is drawn to the left side of the elevation. This is the symbol for first angle projection:

Question 37

What third Angle Projection 

Answer 37

Third angle is most used in the United States and Australia. However, as most CAD packages are produced in the United States, it is not uncommon to see third angle being used t in CAD drawings. When drawing in third angle, the top view is placed above the front view and the right side is drawn to the right side of the elevation. This is the symbol for third angle projection

Question 38

3D Isometric Projection  

Answer 38

Isometric projection is drawn with both sides at 30-degrees and 90-degree vertical lines. A 30° set square is used to read and produce drawings to ensure accuracy.  It is the commonly used method of 3D drawing used in formal technical sheets, as it is quick and gives a good representation of the object, especially when there is a circle (holes or cylinders) on the side faces.   Dimensions are shown accurately and in the correct proportion. This makes it easy to draw the projection to scale from a plan view. Most CAD programs initially draw parts in isometric and pull other views from it

Question 39

Oblique Projection

Answer 39

Oblique projection dates to the 1st or 2nd centuries in China. It was used to draw rectilinear objects such as houses.  Very easy to draw with very little training.  45° angles are easily estimated by novices. It presents a clear front view of an object with an element of 3D appearance. It requires no specialist equipment.