Sine: sine, also known as foot 
 Sine sine defined using the angle and taper measuring gages, etc., also known as sine feet. It mainly consists of a rectangular steel and fixed at both ends of the two the same diameter of steel cylinder form. Two lines from the cylinder axis L is generally 100 mm or 200 mm. The picture shows the use of sine measurement cone gauge the situation. In the right triangle, sinα = H / L, where H is the amount of the block group size, measured by the angle of the nominal point of view considered. Micrometer at both ends according to the indication of the difference may be obtained by the measured angle error. Sine generally used to measure less than 45 ° angle in the measurement of less than 30 ° angle, the precision of up to 3 "5." 
 Sine is in line with the principle use of the block formed by the standard sine angle to the horizontal direction of the workpiece by measuring the angle differential comparisons and inside and outside the cone of a precision measuring instrument. Precision of 0, 1.