can be quickly switched from inches to millime- ters. Outside dimensions are measured using the large jaws. Inside dimensions are measured with the smaller, pointed jaws. Depth measurements can be taken using either the main jaw or depth probe. See Figure 12-10. 12.2.3 Squares There are a number of different kinds of squares. They are used for several purposes, such as: • Checking that corners form a 90° angle (squareness). • Serving as a straightedge. • Measuring distances and angles. Framing and Bench Squares Framing and bench squares are flat steel or alu- minum. A framing square has a 24″ (610 mm) body Tape measure lengths commonly used by cabi- netmakers range from 12′ to 30′ (4 m to 9 m). Tape lengths may be up to 200′ (61 m). Both US custom- ary and metric measurements may be printed on the tape. 12.2.2 Slide Calipers Slide calipers are used to measure outside and inside distances, as well as depth. They come in various types. See Figure 12-9. A vernier scale provides the most accurate measurement but is the most difficult to read. Dial calipers have precision gears, but wood shavings can cause problems if they get into the gears. Digital calipers have become popular in recent years, especially because they Stanley Tools FastCap, LLC Figure 12-8. Two types of tape measures. The bottom tape measure is extra flexible to allow for measuring curved surfaces. Patrick A. Molzahn Figure 12-9. Slide calipers are available in various styles. 152 Section 2 Design and Layout Copyright Goodheart-Willcox Co., Inc.