In NC machining or CNC machining working, we always met the different drawings which marked with different machining standard. That require worker to calculate dimensions with different calculation formula. International Standards MACHINING CALCULATING FORMULA FOR CALCULATING THE BORE DIAMETER OF THE TAPPING OF EXTRUSION WIRE: Formula: External diameter of teeth – 1/2 *pitch Example 1: Formula: M3 * 0.5 = 3 – (1/2 * 0.5) = 2.75mm M6 x 1.0 = 6 – (1/2 x 1.0) = 5.5 mm Example 2: Formula: M3 * 0.5 = 3 – (0.5/2) = 2.75 mm M6*1.0=6-(1.0/2)=5.5 mm. MACHINING CALCULATING FORMULA FOR ENGLISH TAPPING: 1 inch = 25.4mm Example 1: (1/4-30) 1/4 x 25.4 = 6.35 (Pitch Diameter ) 25.4/30 = 0.846 (pitch) The conversion from 1/4-30 to metric screw should be M6.35 * 0.846 Example 2: (3/16-32) 3/16* 25.4=4.76 ( Pitch Diameter ) 25.4/32 = 0.79 (pitch) The conversion from 3/16-32 to metric screw should be M4.76 *0.79 FORMULAS FOR CONVERTING BR...