1.1 This specification covers the requirements for non-heat treated carbon steel machine screws with nominal diameters of No. 0000 through ¾ in. having a minimum ultimate tensile strength of 60 000 psi. This specification covers the requirements for non-heat treated carbon steel machine screws. Steel for the machine screws shall be made by open-hearth, basic-oxygen, or electric-furnace process and the screws shall be manufactured by cold forming, thre