Sketching 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: Tips: 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.