ASME_B18.3-2002.pdf

ASMESOCKET CAP,SHOULDER,SET SCREWS,B18.3SOCKET2002HEX,AND SPLINE KEYSSCREWSIFI NOTES:1.ASME B18.3 is a standard developed through the procedures ofThe American Society of Mechanical Engineers.B18.3 is under thejurisdiction of ASME Standards Committee B18 and is the directresponsibility of its Subcommittee 3.2.B18.3 presents requirements for 6 basic products:hexagon and spline socket head cap screwsdrilled hexagon socket head cap screwshexagon and spline socket flat countersunk head cap screwshexagon and spline socket button head cap screwshexagon socket head shoulder screwshexagon and spline socket set screwsThe standard also includes driving bits and keys for both hexagonand spline socket screws.3.This 2002 standard is a revision of the earlier 1998 version andincludes numerous changes including new quality assurance pro-visions,and gaging techniques for countersunk screws.4.ASME B18.3-2002 is reprinted with the permission of its publisher,The American Society of Mechanical Engineers,Three Park Avenue,New York,NY 10016-5990,U.S.A.1.INTRODUCTORY NOTESare based.However,where questions arise con-ceming acceptance of product,the dimensions1.1Scopein the tables shall govern over recalculation byformula.1.1.1 This standard covers complete generaland dimensional data for various types of hexa-1.1.2 The inclusion of dimensional data in thisgon and spline(fluted)socket cap screws,shoul-standard is not intended to imply that all of theder screws,set screws,and hexagon and splineproducts described are stock production sizes.keys recognized as American National Standard.Consumers should consult with manufacturersAlso included are appendixes that provide speci-concerning lists of stock production sizes.fications for hexagon and spline socket gagesand gaging,tables showing applicability of keys1.2Socket Cap Screwsand bits to various socket screw types and sizes,drill and counterbore sizes for socket head capThe head types covered by this standardscrews,and formulas on which dimensional datainclude the following.2003 Industrial Fasteners InstituteG-ASMEOCKETSOCKET CAP,SHOULDER,SET SCREWS,B18.3CREWSHEX,AND SPLINE KEYS20021.2.1 Socket Head Cap Screws.The socket1.4Socket Set Screwshead shall have flat chamfered top surface withsmooth or knurled cylindrical sides and a flatThe socket set screw is a screw threadedbearing surface.Specifications are given inthe entire length except for its length of point.Tables 1A through 1F,pages G4 thru G-11.The point is designed to bear on a mating part.Both hexagon and spline socket types are in-The common point styles are cup,flat,oval,cone,cluded.and half dog.Specifications for set screws areDimensions for drilled holes and counter-shown in Tables 5A through 5C.pages G-26bores are included in Appendix A,Table A1,pagethru G-31,for both hexagon and spline socketG42.types.1.2.2 Drilled Hexagon Socket Head Cap1.5Keys and Bits for Driving SocketScrews.Specifications for hexagon socket headScrewscap screws having 2,4,and 6 holes drilled inThe tools for driving socket screws arethe head for lock wire application are given inhexagon or spline keys and bits,the specifica-Table 1F,page G-11.tions for which appear in Tables 8 and 9,respec-1.2.3 Socket Flat Countersunk Head Captively,pages G-35 and G-37.Screws.The flat countersunk head shall have1.6Dimensionsa flat top surface and a conical bearing surfacewith included angle of approximately 82 deg.All dimensions in this standard are givenSpecifications are given in Tables 2A,2B,andin inches,unless stated otherwise.2C,pages G-15 thru G-19.Both hexagon andAll dimensions apply prior to coating,un-spline socket types are included.less stated otherwise.1.2.4 Socket Button Head Cap Screws.The1.7Finishbutton head shall have a low rounded top sur-face with a large flat bearing surface.Specifi-Because of the high hardness of thesecations are given in Table 3,page G-20.Bothproducts,it is recommended that they not behexagon and spline socket types are included.electroplated.1.2.5 Socket Low Head Cap Screws.These1.8Identification Markingare similar to socket head cap screws exceptthey have reduced head height and a smallerProducts described in Paras.1.2.1 thrusocket size.They are designed to be used in1.2.4 and 1.3 with diameters larger than#10 mustapplications where height clearance is a prob-be marked with the identification of the sourcelem.Specifications are given in Table 1G.Splinemanufacturer or private label distributor accept-socket types are excluded.ing the responsibility for conformance to thisstandard.Marking size,type and location ofmarks are at manufacturers option.Products1.3Socket Head Shoulder Screwsshall not be marked on bearing surface.The socket head shoulder screw is a1.9Optionshexagon socket head screw having a cylindricalshoulder under the head.Specifications areOptions,where specified,shall be at thegiven in Table 4,page G-23.discretion of the manufacturer,unless agreedG-22003 Industrial Fasteners InstituteASMESOCKET CAP,SHOULDER,SET SCREWS,B18.3SOCKET2002HEX,AND SPLINE KEYSSCREWSupon otherwise by the manufacturer and pur-2.1.2 Spline Sockets.Spline sockets shallchaser.conform with the specifications given in Table 7,page G-34.1.10Responsibility for ModificationsThe manufacturer shall not be held re-2.2Threadssponsible for malfunctions of product due to plat-ing or other modifications,when such plating orThreads on all screw products coveredmodification is not accomplished under his con-by this standard shall be in accordance withtrol or direction.ASME B1.1,page A-33,for the series and classspecified in the notes to the respective product1.11Terminologydimensional tables.Acceptability of screw threads shall beFor definitions of terms relating to fas-based on System 22 in accordance with ASMEteners or to component features thereof used inB1.3M.page A-63,except where otherwisethis standard,refer to ASME B18.12,Glossarynoted in Note 5 of Table 5A,page G-28.of Terms for Mechanical Fasteners,page N-1.2.3Quality Assurance1.12 Referenced StandardsTitles and sources of availability of refer-Products will be furnished in accordanceenced standards are given on page N-38.with ASME B18.18.1,page M-5,with the threadacceptability to Inspection Level C,unless oth-2.GENERAL DATAerwise specified.2.1Sockets2.4Dimensional CharacteristicsIn accordance with the provisions setforth in the notes to the respective dimensionalProducts shall conform to the dimensionstables,screws shall have hexagon or spline sock-indicated in the respective tables.The desig-ets as designated by the purchaser.nated characteristics defined within the notes ofGages and gaging procedures are in-each product table shall be inspected in accord-cluded in Appendix I.For coated products,useance with ASME B18.18.2.For nondesignatedGO gages identical in design and tolerances todimensional characteristics the provisions ofthose shown in Appendix I.page G-38,exceptASME B18.18.1 shall apply.Should a nondes-having minimum dimensions equal to minimumignated dimension be determined to have asizes of keys and bits shown in Tables 8 and 9,variance,it shall be deemed conforming to thisrespectively,pages G-35 and G-37.Due to pos-standard if the user,who is the installer acceptssible buildup of the socket,coated products maythe variance based on fit,form,and function con-not accept a standard hex or spline key.siderations.Where verifiable in-process inspec-tion is used in accordance with ASME B18.18.32.1.1 Hexagon Sockets.Hexagon socketsor ASME B18.18.4M,the final inspection levelshall conform with the specifications given insample sizes of those respective standards shallTable 6,page G-33.apply.2003 Industrial Fasteners InstituteG-3