Calipers are used most often when wood turn- ing. When the lathe is stopped, you can check or transfer thicknesses and distances. Outside Caliper An outside caliper checks outside diameters on turnings. See Figure 12-21. First, set the caliper with a rule. Then turn the material until the caliper slips over it. When making duplicate parts, set the caliper by the workpiece being copied. Inside Caliper An inside caliper checks inside diameters. Pre- set the caliper with a scale. Then turn the work until the diameter is reached, Figure 12-22. A B C D E The L.S. Starrett Co. Figure 12-20. Calipers are used to transfer outside and inside measurements and parallel lines. A—Firm-joint outside calipers. B—Bow-spring outside calipers. C—Firm-joint inside calipers. D—Bow-spring inside calipers. E—Hermaphrodite calipers. The L. S. Starrett Co. Figure 12-21. Set and use the outside caliper to check diameter measurements. The L.S. Starrett Co. Figure 12-22. The inside caliper is set and used to check dimensions on the inside of round material. 1 1 2 Chapter 12 Measuring, Marking, and Laying Out Materials 157 Copyright Goodheart-Willcox Co., Inc.