Charles J. Kachmar

Charles J. Kachmar

• Drafting is a graphic language having its own alphabet and grammar.

• Two main classes of technical drawing:– Artistic and Technical.

• Artistic express emotions, philosophic or aesthetic ideas.

• Technical drawings show how objects really are.

• We can all see the importance of sketches, especially if we recall the previous exercise.

• Sketches are more often used instead of complete mechanical drawings where changes must be made in a hurry:– Saves expenses– Time– Inventor may not be versed in drafting

• Materials for sketching:– Pencil– Eraser– Paper

• Crossed sectioned paper is often used (graph paper) with 1/8” or 1/4” squares.

• Sketches are not drawn to exact scale but should be proportionate.

• In sketching it is important to:– Draw Straight Lines, Use Small Strokes.

• Tips: • Keep your eye on the point you are headed for.

• Think Ahead.

• Swing pencil back and forth between the points.

• Go Quickly as to reduce the shakes.

• Don’t squeeze the pencil too tight.

• Finally strike the page firmly, with a free and easy wrist- and - arm motion

• USE THE FORCE!

• Spacing Tips:

• Use the pencil and your fingers to space on your sketch.

• Draw margins, center marks and division marks on page.

• Proportions:

• Make or break the sketch.

• It is important that the sketch represent the items in proportion to all the parts. (Example) Car with balloon tires.

• More tips…

• Draw big areas first, the add the detail later.

• Quadrant rule.

• Scale….what is meant by drawing to scale?

• Estimating Proportion: Proportions make or break the sketch.

• A sketch is in proportion if all of the components of that sketch are sized in comparison to the other elements.

• If you are to draw the front view of an object you need to have the width and the height.

• To draw the top of the object you need the width and the depth.

• To draw the right side you need to have the depth and the height.

• Pencil Sharpening:

• Sharp: Center Lines, Dimension Lines and Extension Lines. Also Lettering.

• Nearly Sharp: Hidden Lines

• Slightly Dull: Visible Lines

• Slightly Dull and light lead (no. 3): Construction Lines

• Sketch small circles with:– Paper/string compass rule– Rotate the paper method– Two pencils– Build a circle with points in intersecting lines.

• What is a radius? What is the diameter?

• Sketching Ellipses requires a little skill:

• Trammel Method:– Major Axis is x axis– Minor Axis is the y axis– Eye the four tangent points at 90, 180, 270 and

360 degrees.