Freehand Technical Sketching

1
Freehand Technical Sketching

• Chapter 4
• Page 27

2
Objectives

• Identify materials needed to do freehand
  sketching.
• Sharpen pencil properly.
• Hold pencil properly.
• Sketch horizontal, vertical, and inclined lines.
• Sketch arcs, circles, and elipses.
• Identify aids needed to do freehand sketching.

3
Purpose of freehand sketching

• Freehand sketching allows a drafter or technician
  to convey ideas quickly and easily.
• Saves time if corrections need to be made.

4
Sketching Techniques

• Hold pencil loosely enough so that it has a free
  and easy movement.
• Rotate pencil to maintain a sharp point.
• Dont apply too much pressure and gouge the paper
  so it wont erase.
• Use short, light lines instead of one continueous
  one.

5
Horizontal Lines

• 1. Locate and mark the end points of the line.
• 2. Sketch short, light lines between the points.
• 3. Darken the line to form one continuous line
  of uniform weight.

6
Vertical Lines

• 1. Locate and mark the end points of the line.
• 2. Sketch short, light lines between the points.
• 3. Darken the line to form one continuous line
  of uniform weight.

7
Inclined lines and angles

• 1. Start by creating a 90 degree angle with
  horizontal and vertical lines.
• 2. Cut the 90 degree angle in half to form two
  angles of 45 degrees.
• 3. Continue to cut the angles until you get
  close to the desired angle.

8
Arcs, Circles, and Elipses

• One method is the triangle square method.

9
Proportion in Sketching

• Proportion is the relationship between the size
  of one part to another and to the object as a
  whole.
• The unit method can establish a relationship
  between features that will make the features look
  like they are the size they should be.

10
Objectives Covered.

• Identify materials needed to do freehand
  sketching.
• Sharpen pencil properly.
• Hold pencil properly.
• Sketch horizontal, vertical, and inclined lines.
• Sketch arcs, circles, and elipses.

11
Assignment

• Do exercises 4-PR-5 and 4-PR-6 on pages 36 and
  37.
• Sketch the objects as large as possible on a
  piece of plain white paper.
• DO NOT TRACE!!!!!!!!!!