You'll often see the angle of a dovetail expressed as a ratio of slope to rise (1:8, for example) instead of in degrees. Why? Because it's easier to set a bevel gauge using a ratio instead of a degree setting. Here's how.If, for example, your project calls for a 1:8 dovetail ratio, mark a 1"-long segment on the edge of a piece of paper. Then, starting at one end of the line, draw a perpendicular line 8" long. Use a straightedge to join the ends of the two lines to make a triangle; then place your bevel-gauge handle along the edge of the paper and pivot the blade to align with the long line.—from the WOOD shop