Engineering Design 1 - Week 17 Lecture - Dimensioning Engineering Drawings

Auxiliary View

A view created to show a feature that cannot be clearly seen in standard views.

Section View

A view created by slicing through a part to show interior details.

Centerline

A line that indicates the center of revolved features for reference in dimensions.

Center Mark

A symbol used to indicate the center of circular features.

PCD (Pitch Circle Diameter)

Measurement of the diameter of an imaginary circle drawn through bolt centers.

Dimensioning

The process of creating a technical drawing with specific measurements.

Unidirectional Dimensions

Dimensions that are read from one direction, typically from the bottom left.

Aligned Dimensions

Dimensions that are aligned with the corresponding dimension lines.

Chain Dimensioning

A method of dimensioning where dimensions are placed sequentially.

Parallel Dimensioning

A method of dimensioning where all dimensions are related to a common feature.

Diameter Symbol (Ø)

A symbol used to indicate the diameter of circular features.

Radius Symbol (R)

A symbol that indicates the radius measurement of a circular feature.

Technical Drawing

A detailed graphical representation of an engineering object.

Countersink

A conical hole cut into a material to allow the head of a countersunk screw to sit flush with or below the surface.

Counterbore

A cylindrical recess around a hole that allows the head of a bolt or screw to sit beneath the surface.

Holes

Cylindrical voids or openings in a material, defined by diameter and depth.

Dimension Rules

Guidelines that dictate how dimensions should be applied and understood in technical drawings, ensuring clarity and accuracy.

Depth of Hole

The measurement from the surface to the bottom of the hole.

Threaded Hole

A hole that has internal threads for fastening with a screw or bolt.

Blind Hole

A hole that does not go all the way through the material.

Through Hole

A hole that passes completely through a part.

Standard Dimensioning Practices

Common conventions used to avoid ambiguity in dimensioning, such as the use of specific units and clear indication of features.

Tolerance

The permissible limit of variation in a physical dimension.