One of the main advantages of sketching is that few materials are required. Basically, you need only a pencil and paper. However, the type of sketch prepared and your personal preference will determine the materials used.

You should use a soft pencil in the grade range from F to 3H, with H being a good grade for most sketching. The pencil should be long enough to permit a relaxed but stable grip. As you gain experience, you may even prefer to use fine tip felt pens. (Dark- or bright-colored pens should be used.) Felt tip pens work very well on overlay sketches (discussed later).

Most of your sketches will be done on scratch paper, which can be any type or size of paper. An experienced draftsman will keep a pad of 3 in. by 5 in. or 5 in. by 8 in. scratch paper handy at all times. For planning the layout of a drawing, you will find tracing paper to be convenient. The advantage of sketching on tracing paper is the ease with which sketches can be modified or redeveloped simply by placing transparent paper over previous sketches or existing drawings. Sketches prepared in this manner are referred to as OVERLAY SKETCHES. Cross-section or graph paper may be used to save time when you are required to draw sketches to scale. (See fig. 5-56.) Isometric sketches are easily done on specially ruled isometric paper. (See fig. 5-57.)

An eraser maybe used, but you will probably do very little erasing. Sketches usually can be

Figure 5-56.-Use of cross-sectional paper in technical sketching.

Figure 5-57.-Use of specially ruled isometric paper in technical sketching.

redrawn more quickly than mistakes can be erased.

For making dimensioned sketches in the field, you will need some sort of measuring tapeeither a pocket rule or a surveyors tape, depending on the extent of the measurements taken. If you are required to collect extensive field data, it would be to your benefit to maintain a sketch notebook. A surveyors field notebook works well for this purpose.