ASME B18.3 pdf download Socket Cap, Shoulder, Set Screws, and Hex Keys (Inch Series)
1.1 Scope This Standard covers complete general and dimen- sional data for various types of hexagon socket cap screws, shoulder screws, set screws, and hexagon keys recognized as an American National Standard. Also included are appendices that provide specifications for hexagon socket gages and gaging, tables showing appli- cability of keys and bits to various socket screw types and sizes, drill and counterbore sizes for socket head cap screws, and formulas used for dimensional data. However, where questions arise concerning acceptance of product, the dimensions in the tables shall govern over recalculation by formula. Recess dimensions for Type VI recesses are given in Mandatory Appendix III.
1.2 Socket Cap Screws The head types covered by this Standard are specified in paras. 1.2.1 through 1.2.5.
1.2.1 Socket Head Cap Screws. The socket head shall have a flat chamfered top surface with smooth or knurled cylindrical sides and a flat bearing surface. Specifications are given in Tables 1 through 7. Dimen- sions for drilled holes and counterbores are included in Table A-1 of Nonmandatory Appendix A.
1.2.2 Drilled Hexagon Socket Head Cap Screws. Specifications for hexagon socket head cap screws hav- ing two, four, and six holes drilled in the head for lock wire applications are given in Table 7.
1.2.3 Socket Flat Countersunk Head Cap Screws. The flat countersunk head shall have a flat top surface and a conical-bearing surface with an angle of approxi- mately 82 deg. Specifications are given in Tables 8 through 10.
1.2.4 Socket Button Head Cap Screws. The button head shall have a low rounded top surface with a large flat bearing surface. Specifications are given in Table 11.
1.2.5 Socket Low Head Cap Screws. These are simi- lar to socket head cap screws, except they have reduced head height and a smaller socket size. They are designed to be used in applications where height clearance is a problem. Specifications are given in Table 12.
1.3 Socket Head Shoulder Screws The socket head shoulder screw is a hexagon socket head screw having a cylindrical shoulder under the head. Specifications are given in Table 13.
1.4 Socket Set Screws The socket set screw is a screw threaded the entire length except for its length of point. The point is designed to bear on a mating part. The common point styles are cup, flat, oval, cone, and half dog. Specifica- tions for set screws are shown in Tables 14 through 16.
1.5 Keys and Bits for Driving Socket Screws The tools for driving socket screws are hexagon keys and bits. Table 17 contains the requirements for hexagon keys and bits.
1.6 Dimensions All dimensions in this Standard are given in inches unless stated otherwise. All dimensions apply prior to coating unless stated otherwise.
1.7 Finish Because of the high hardness of these products, it is recommended that they not be electroplated.
1.8 Identification Marking Products described in paras. 1.2.1 through 1.2.4 and 1.3 with diameters larger than #10 shall be marked with the identification of the source manufacturer or private label distributor accepting the responsibility for confor- mance to this Standard. Marking size, type, and location of marks are at manufacturer’s option. Products shall not be marked on bearing surface.
1.9 Terminology For definitions of terms relating to fasteners or to component features thereof used in this Standard, refer to ASME B18.12, Glossary of Terms for Mechanical Fasteners.
1.10 Responsibility for Modifications The manufacturer shall not be held responsible for malfunctions of product due to plating or other modifi- cations, when such plating or modification is not accom- plished under his control or direction.
2 GENERAL DATA 2.1 Sockets Unless otherwise specified, screws shall have hexagon sockets in accordance with the provisions set forth in the notes to the respective dimensional tables.
2.1.1 Hexagon Sockets. Hexagon sockets shall con- form to the specifications given in Table 18. Gages and gaging procedures are included in Mandatory Appendix I.
2.1.2 Type VI Sockets. Type VI recesses shall con- form to the specifications given in Mandatory Appendix III. Gages and gaging procedures are included in Mandatory Appendix III.
2.2 Threads Threads on all screw products covered by this Standard shall be in accordance with ASME B1.1 for the series and class specified in the notes to the respective product dimensional tables. Acceptability of screw threads shall be based on System 22, ASME B1.3, except where otherwise specified in Note (12) of Table 14.