ME 101 Drafting

Basics

Linetypes, Title Blocks, Basic Geometry,

Sketching Techniques, Projection Views, One

and Two View Drawings, and Arrangement of

Views

* Indicates what we focus on

Most common objects (or some variation)

● Spherical Objects

○ Diameter

● Cylindrical Shapes

○ Diameter + Length (or height)

● Rectangular Shapes

○ Width, Length, and Height

● Other Shapes

○ (Some form of) Width, Length, and Height

Most common standards

● American Society of Mechanical Engineers (ASME)*

○ Most Prominent in the USA

○ Uses both inches and millimeters

○ We will be using and learning the ASME Y-14 series

● Canadian Standards Association (CSA)

● International Organization for Standardization (ISO)*

● Milspec (Military drafting standard)

● Japanese Industrial Standard (JIS)

Title block and Format

● Always states the standards/ units

● Drawings are a legal document

● Clear Communication

A couple versions of a

title block

Difference between dimensioning schemes

Which one of these schemes is easier to decipher features and dimensions?

Importance of Orthographic Views

● Orthographic Views used to see features and dimensions easier

● Usually three primary views:

○ FRONT, TOP, and RIGHT Views/Planes

Also there are different

types of orthographic

views, but we will get to

that later.

1st angle versus 3rd angle projection

● Two different types of projection for orthographic views (1st and 3rd)

● 3rd angle

○ Primarily used in the USA

○ Very easy to understand

● 1st angle

○ Primarily used in the international community

○ Be careful to check which projection

1st angle versus 3rd angle projection

● Easier way to remember the symbols

● Imagine you have a bowl and part sitting in it, and you’re viewing it from the top

○ As you rotate 90 degrees, you get an orthographic view

1st Angle 3rd Angle

3rd Angle Projection

1st Angle Projection

Which Angle Projection is this one?

Another 3rd Angle Projection example

The drafter must take the number of dimensions shown, geometry, minimization of

hidden lines, etc. when considering which face is the Front view.

More 3rd angle projections (hidden features)

Line Styles

● Visible Line*

○ For dimensions and outlines of visible features

● Hidden Lines*

○ For showing hidden features in orthographic views

● Center Line*

○ For construction of features and patterns

○ Also for denoting holes and cylindrical components

● Long Break Line

○ Denoting Long and continuous parts

■ Think Broomstick

● Section Lines

○ Used for cross-sections to denote the internal

components

● Cutting-Plane Line

○ To show cross-sections and internal features

● Reference Line

○ Used for construction and geometry

Miter Line (For drafting)

● Miter line is used to when drafting by hand.

○ Used to show how features transfer from one view to another.

Symbols and Abbreviations

● IN : inches*

● mm: millimeters*

● FT: feet (used for much larger projects)

● Φ: diameter of a hole or cylindrical feature*

● R: radius*

Center Marks

● Used for denoting the location of the center-point of a circle, circular features, or arcs.

Functional Drafting

There are many ways to reduce drafting time in preparing a drawing:

● Avoid Unnecessary views

● Use simplified drawing practices

● Use explanatory notes to compliment the drawing, thereby eliminating views that are

time consuming to draw

● Eliminate unnecessary lines

Applying the functional drafting techniques

Next time we will start looking

into dimensioning schemes

Dimensioning basics

● Origin

● Baseline

● Chain