This Gulf standard gives a series of cones or conical tapers, ranging from 120o to less than 1: or ratios from 1: 0,289 to 1: 500. intended for general use in mechanical engineering. It applies only to plain non-threaded conical surfaces and excludes prismatic pieces, taper threads, bevel gears, etc. Series 1 and 2, as specified in Table 1, shall be used in this order of preference, with a view to reducing the range of tools, gauges and measuring instruments required for production of conical parts. Table 2 shall be used only for the particular applications indicated in the last column. These tables give calculated values for cone angle or rate of taper to facilitate design, production, and control of conical pieces. The method of dimensioning conical surfaces on drawings is covered in the Gulf standard to be approved by GSO on “Technical drawings - dimensioning and tolerancing – cones” (ISO - 3040).