scope:

This Standard covers the complete general and dimensional data for eight product types of inch series square and hex bolts and screws recognized as American National Standard. Also included are appendixes covering thread runout sleeve gages, gaging procedure for checking bolt and screw straightness, grade markings for steel bolts and screws, formulas on which dimensional data are based, and a specification to assist in identifying a product as being a screw or a bolt. It should be understood, however, that where questions arise concerning acceptance of product, the dimensions in the tables shall govern over recalculation by formula. Heavy hex structural bolts, formerly covered in ANSI B18.2.1, are now covered in ASME B18.2.6.

The inclusion of dimensional data in this Standard is not intended to imply that all of the products described herein are stock production sizes. Consumers should consult with manufacturers concerning lists of stock production sizes.

Square and Hex Bolts and Screws purchased for Government use shall conform to this Standard and to any additional requirements specified in the purchase order or contract. See Appendix E for the Government Part Identifying Numbering System (PIN code) and other requirements for hexagon head cap screws.