This SAE Part Standard covers selected machine screws manufactured in accordance with American Society for Mechanical Engineers dimensional standards. This SAE standard covers material most often used in ship systems and equipment but its use may be applied wherever fasteners of the covered materials are used. This document permits the fasteners to be identified and ordered by a part or identifying number (PIN) as defined in this document. Purpose The purpose of this document is to assist the designer and other personnel in providing requirements and part identifying numbers for the most commonly used machine screws for ship systems and equipment. A part or identification number is normally required for all military applications and provides a useful means of communicating fastener requirements to suppliers and manufacturers in a very succinct manner. Machine Screw Part Numbers This document provides part or identifying numbers that can be used to identify machine screws covered by this document. The parts covered by this document are manufactured in accordance with materials and processes identified in standards issued by ASTM. The part identification number (PIN) identifies the thread form, type of head, type of drive, nominal diameter, special features (plating, locking elements), nominal length and fastener material.