Design Drafting Lectures Lecture 1

Introduction: Tools and Trades

Drafter Defined:

Drafters translate ideas and sketches of engineers, architects, and scientists into detailed drawings which are used in manufacturing and construction. Their duties may include interpreting directions given them, making sketches, preparing drawings to scale and specifying details. Drafters may also calculate the strength, quality, quantity and costs of materials. They utilize drafting tools, engineering practices and math to complete drawings.

Drafting Occupations:

There are several types of drafting technology occupations.

Drafting Occupation Types:

ArchitecturalLandscapeElectrical (construction wiring)AeronauticalElectronic (schematics etc)CivilStructuralCastingsPatentTool Design

Directional Survey (oil and gas boreholes)GeologicalGeophysicalHVACPlumbingAutomotive DesignOil and Gas (refineries, fields)Technical IllustrationCartographicPhotogrammetric (aerial maps)

The type of drafting we will be studying is called mechanical drafting. It is the typical foundation of all drafting fields.

Mechanical Drafter:

1. Responsible for the production of detailed working drawings of machinery and mechanical devices.

The tools that a drafter uses to communicate are called drafting equipment. This lecture will focus on the various types of drafting machines, pencils, leads and sharpeners.

Drafting Machines:

1. Two types: Elbow and Track

Note: Elbow only work in the horizontal position. Many drafters prefer to stand and or work in vertical position.

2. Types of Track drafting machines:a. Standardb. Digital Displayc. Coordinate Reading and Processing

The use of the standard track drafting machine will be demonstrated in class.

Parallel Bar:

1. The parallel bar slide up and down the board to allow you to draw horizontal lines.2. Vertical lines and angles are made with triangles in conjunction with the parallel bar.3. The parallel bar is commonly found in architectural drafting offices because

architectural drawings are frequently very large. Architects often need to draw straight lines the full length of their boards and the parallel bar is ideal for such lines.

Drafting Pencils, Leads, and Sharpeners:

1. A mechanical pencil is applied to a pencil which requires a piece of lead (graphite) to be manually inserted and mechanically or semi-automatically advanced to the tip.

LEAD HOLDER

For proper use, the lead should extend about ¼” beyond the end of the chuck.

Always sharpen the end opposite the grade designation.

2. An automatic pencil refers to a pencil with a lead chamber that, at the push of a button advances the lead from the chamber to the writing tip and when a new piece of lead is needed, advance the new piece to the tip.

Automatic pencils are designed to hold leads of one width so you do not need to sharpen the lead.

3. Wooden pencils are occasionally used by draftsmen who like to chisel letter.

4. Leads come in two (2) grades ranging from the hardest (thinnest) being 9H to the softest (biggest) 9B.

9H – 4H used for construction lines3H – B used for linework, lettering, and sketching 2B – 7B uses for art work

Thick lines: 2H – FThin lines: 4H – H

Construct: 9H – 4H

5. Polyester (plastic) Leads are used for drawing on polyester drafting film, often called by its trade name Mylar.

6. Colored leads have special purposes.

a. Red – Corrections, shadingb. Blue – guidelines, construction lines (non-photo blue lead will not copy or

blueprint)

7. Lead holders should be tilted 45 to 60 degrees with the direction of travel, also providing a twisting action to keep the tip conical.

8. Automatic pencils do not require a tilt or twisting motion because the lead breaks easily.

9. Sanding blocks should be placed in a plastic bag after use.

10. Lead pointers (demonstrated in class)

11. Lead pointer attachment for electric eraser.

Basic Drafting Equipment (Recommended)

Drawing Board (Drafting Table)

T-Square, Parallel ruling straightedge (parallel slide), or drafting machine

Drawing sheets (paper or film)

Drafting pencils

Erasers

Erasing Shield

Triangles: 45° and 30/60° (not required with drafting machines)

Scales: Civil and Architectural (some may choose a combination scale), and a Metric Scale

Templates (not used with CADD drafting)

Brush

Calculator

Positions within a Drafting Office

Various Fields in Drafting