to an angle or a corner, the body bisects the angle. This angle helps when cutting miter joints. See Figure 12-19A. Angle dividers have numbers on the body and an index mark on the adjusting nut. The numbers on the side of the nut are 30°, 45°, and 60°. Accurately aligning the index mark along these numbers sets the blades to that angle. The numbers on the other side of the nut are 4, 5, 6, 8, 10, and 0. These indicate settings for polygons. Aligning the index nut at 6 will set the angle of the blades for a hexagon (a six- sided polygon). The angle between the blades will be 120°. The body will bisect the angle at 60°. When the index mark is set at 0, the blades form a straight line with the body. 12.3.3 Calipers Calipers are used to transfer dimensions. The three types of calipers are outside, inside, and her- maphrodite. See Figure 12-20. Some are assembled with a firm (friction) joint. Others have a bow spring with an adjusting screw and nut. Firm-joint calipers are quicker to adjust, but bow-spring calipers main- tain greater accuracy during use. Goodheart-Willcox Publisher Figure 12-17. Framing and bench squares are used for measuring, marking, and checking squareness. Goodheart-Willcox Publisher Figure 12-18. The T-bevel has a body, blade, and locking device. A—Setting the angle with a protractor. B—Marking the wood. General Hardware Figure 12-19. Angle dividers are helpful when setting angles for cutting miter joints. Angle for miter cut A A B B Laying Out an Octagon Picture Frame To lay out an octagon picture frame, proceed as follows: 1. Set the index mark even with the 8. 2. Hold the body of the angle divider against the edge of the frame material. 3. Mark the mitering angle and saw the workpiece on that line. See Figure 12-19B. Procedure 156 Section 2 Design and Layout Copyright Goodheart-Willcox Co., Inc.