Machine Screws and Machine Screw Nuts€¦ · ASME B18.6.3-2003 (Revision of ASME B18.6.3-1998) ASME B18.6.3–2003 (Revision of ASME B18.6.3–1998) Machine Screws and Machine Screw

A N A M E R I C A N N A T I O N A L S T A N D A R D

Machine Screws and Machine Screw Nuts

ASME B18.6.3-2003(Revision of ASME B18.6.3-1998)

ASME B18.6.3–2003(Revision of ASME B18.6.3–1998)

Machine Screwsand MachineScrew Nuts

A N A M E R I C A N N A T I O N A L S T A N D A R D

Three Park Avenue • New York, NY 10016

Date of Issuance: June 30, 2005

The 2003 edition of this Standard is being issued with an automatic addenda subscription service.The use of addenda allows revisions made in response to public review comments or committeeactions to be published as necessary. This Standard will be revised when the Society approves theissuance of a new edition.

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The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990

Copyright © 2005 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

All rights reservedPrinted in U.S.A.

CONTENTS

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viCommittee Roster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viiiCorrespondence With the B18 Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

1 Introductory Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 General Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Tables1A Dimensions of Slotted Flat Countersunk Head Machine Screws. . . . . . . . . 61B Dimensions of Type I Cross Recessed Flat Countersunk Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71C Dimensions of Type IA Cross Recessed Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81D Dimensions of Type II Cross Recessed Flat Countersunk Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91E Dimensions of Type III Square Recessed Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102A Dimensions of Slotted 100 deg Flat Countersunk Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112B Dimensions of Type I Cross Recessed 100 deg Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122C Dimensions of Type IA Cross Recessed 100 deg Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132D Dimensions of Type II Cross Recessed 100 deg Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143A Dimensions of Slotted Close Tolerance 100 deg Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153B Dimensions of Type I Cross Recessed Close Tolerance 100 deg Flat

Countersunk Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163C Dimensions of Type IA Cross Recessed Close Tolerance 100 deg

Flat Countersunk Head Machine Screws. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173D Dimensions of Type II Cross Recessed Close Tolerance 100 deg Flat

Countersunk Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184A Dimensions of Slotted Oval Countersunk Head Machine Screws. . . . . . . . 204B Dimensions of Type I Cross Recessed Oval Countersunk Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224C Dimensions of Type IA Cross Recessed Oval Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244D Dimensions of Type II Cross Recessed Oval Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264E Dimensions of Type III Square Recessed Oval Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285A Dimensions of Slotted Undercut Flat Countersunk Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295B Dimensions of Type I Cross Recessed Undercut Flat Countersunk Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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5C Dimensions of Type IA Cross Recessed Undercut Flat CountersunkHead Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5D Dimensions of Type II Cross Recessed Undercut Flat CountersunkHead Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5E Dimensions of Type III Square Recessed Undercut Flat CountersunkHead Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6A Dimensions of Slotted Undercut Oval Countersunk Head MachineScrews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6B Dimensions of Type I Cross Recessed Undercut Oval CountersunkHead Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

6C Dimensions of Type IA Cross Recessed Undercut Oval CountersunkHead Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6D Dimensions of Type II Cross Recessed Undercut Oval CountersunkHead Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

6E Dimensions of Type III Square Recessed Undercut OvalCountersunk Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

7A Dimensions of Type I Cross Recessed Flat Countersunk Trim HeadMachine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

7B Dimensions of Type IA Cross Recessed Flat Countersunk Trim HeadMachine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

7C Dimensions of Type II Cross Recessed Flat Countersunk Trim HeadMachine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

8A Dimensions of Type I Cross Recessed Oval Countersunk Trim HeadMachine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

8B Dimensions of Type IA Cross Recessed Oval Countersunk Trim HeadMachine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

8C Dimensions of Type II Cross Recessed Oval Countersunk Trim HeadMachine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

9A Dimensions of Slotted Pan Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . 519B Dimensions of Type I Cross Recessed Pan Head Machine Screws . . . . . . . 529C Dimensions of Combination Slotted — Type I Cross Recessed Pan

Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539D Dimensions of Type IA Cross Recessed Pan Head Machine Screws . . . . . 549E Dimensions of Combination Slotted — Type IA Cross Recessed Pan

Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559F Dimensions of Type II Cross Recessed Pan Head Machine Screws . . . . . . 569G Dimensions of Type III Square Recessed Pan Head Machine Screws . . . . 579H Dimensions of Combination Slotted — Type III Square Recessed

Pan Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5810A Dimensions of Slotted Fillister Head Machine Screws . . . . . . . . . . . . . . . . . . 5910B Dimensions of Type I Cross Recessed Fillister Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6010C Dimensions of Type IA Cross Recessed Fillister Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6110D Dimensions of Type II Cross Recessed Fillister Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6210E Dimensions of Type III Square Recessed Fillister Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6311 Dimensions of Slotted Drilled Fillister Head Machine Screws. . . . . . . . . . . 6412A Dimensions of Slotted Truss Head Machine Screws . . . . . . . . . . . . . . . . . . . . 6512B Dimensions of Combination Slotted — Type I Cross Recessed Truss

Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6612C Dimensions of Type I Cross Recessed Truss Head Machine Screws . . . . . 6712D Dimensions of Type IA Cross Recessed Truss Head Machine Screws . . . . 6812E Dimensions of Type II Cross Recessed Truss Head Machine Screws. . . . . 6912F Dimensions of Type III Square Recessed Truss Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

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12G Dimensions of Combination Slotted — Type III Square RecessedTruss Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

13A Dimensions of Slotted Binding Head Machine Screws . . . . . . . . . . . . . . . . . . 7213B Dimensions of Type I Cross Recessed Binding Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7313C Dimensions of Type IA Cross Recessed Binding Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7413D Dimensions of Type II Cross Recessed Binding Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7513E Dimensions of Type III Square Recessed Binding Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7614A Dimensions of Plain and Slotted Regular and Large Hex Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7814B Dimensions of Type I Cross Recessed Indented Regular and Large

Hex Head Machine Screws. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8014C Dimensions of Type I Cross Recessed Non-Indented Regular and

Large Hex Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8215A Dimensions of Plain and Slotted Hex Washer Head Machine Screws. . . . 8315B Dimensions of Type I Cross Recessed Indented Hex Washer Head

Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8515C Dimensions of Combination Slotted — Type I Cross Recessed

Indented Hex Washer Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . 8716A Dimensions of Slotted Round Head Machine Screws . . . . . . . . . . . . . . . . . . . 8816B Dimensions of Type I Cross Recessed Round Head Machine Screws . . . . 8916C Dimensions of Combination Slotted — Type I Cross Recessed

Round Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9016D Dimensions of Type IA Cross Recessed Round Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9116E Dimensions of Combination Slotted — Type IA Cross Recessed

Round Head Machine Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9216F Dimensions of Type II Cross Recessed Round Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9316G Dimensions of Type III Square Recessed Round Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9417A Dimensions of Slotted Round Washer Head Machine Screws . . . . . . . . . . . 9517B Dimensions of Type I Cross Recessed Round Washer Head Machine

Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9618 Dimensions of Square and Hex Machine Screw Nuts. . . . . . . . . . . . . . . . . . . 9719 Dimensions of Header Points for Machine Screws Before Threading . . . . 98

Mandatory AppendicesI Protrusion Gaging of Flat Countersunk Heads . . . . . . . . . . . . . . . . . . . . . . . . . 99II Across-Corners Gaging of Hex Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100III Gaging of Recessed Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101IV Wobble Gaging of Recessed Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110V Dimensions for No. 0000, No. 000, and No. 00 Thread Sizes . . . . . . . . . . . . 113

Nonmandatory AppendicesA Formulas for Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114B Wrench Openings for Hex Head Screws, and Square, and Hex Nuts . . . . 122

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FOREWORD

American National Standards Committee B18 for thestandardization of bolts, screws, nuts, rivets, and similarfasteners was organized in March 1922, as SectionalCommittee B18 under the aegis of the American Engi-neering Standards Committee (later the American Stan-dards Association, then the United States of AmericaStandards Institute and, as of October 6, 1969, the Ameri-can National Standards Institute, Inc.), with the Societyof Automotive Engineers and the American Society ofMechanical Engineers as joint sponsors. Subcommittee31 was subsequently established and charged with theresponsibility for technical content of standards coveringslotted and recessed head screws.

An American Standard setting forth slotted head pro-portions was approved and published in April of 1930.Over the years following the Issuance of this document,the need for standards more comprehensive than headconfigurations became apparent. At a meeting held onApril 14, 1942, Subcommittee 31 was reorganized andenlarged, and the following operating scope was estab-lished:

The scope of Subcommittee 31 shall consist of thedevelopment and promulgation of American Standardsembracing screw products variously known as machinescrews, wood screws, tapping screws, slotted head capscrews, slotted headless set screws, and machine screwnuts. The standards shall comprise complete productstandards covering all dimensions and tolerancesrequired for the specification and production of theproducts. Details shall include boundary dimensions,such as nut width and thickness; screw head dimensions;slot and recess dimensions; body dimensions; threadclassification or thread detail, as required; thread length;point design; chamfers; underhead fillets; and support-ing general specifications covering the quality, finish,and the acceptable tolerances and limits as well as anyinformation that may be necessary to insure satisfactoryapplication of the products.

Several meetings of the Subcommittee over the ensu-ing 3 years resulted in the development and acceptanceof a proposed revision containing complete productstandards coverage for slotted and recessed headmachine, tapping and wood screws; slotted head andhexagon head cap screws; and slotted headless setscrews. Following approval by the B18 Committee andsponsor organizations, this proposal was forwarded tothe American Standards Association and declared an

1 As of April 1, 1966, Subcommittee 3 was redesignated Subcom-mittee 6.

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American Standard, ASA B18.6, on April 12, 1947.Recognizing the need for further refinements, Sub-

committee 31 at a meeting held on February 1, 1951,established three standing working subgroups: one todevelop details pertinent to tapping screw threads; asecond to review, revise, and develop head dimensionsand tolerances; and a third to correlate and edit thetechnical information emanating from the other twogroups. Also at this meeting, numerous suggestedchanges were reviewed and assigned to the respectivesubgroups for further development. Additional meet-ings of the Subcommittee were held on October 9, 1952,October 29, 1953, and April 1 and 2, 1954. Between eachof these meetings the subgroups held numerous work-ing sessions and carried on technical development incooperation with the technical committees of the U.S.Machine Screw and Tapping Screw Service Bureaus.

At the April 1954 meeting, Subcommittee 3,1 conte-mplating a partial revision of the ASA B18.6 document,recommended the publication of standards for woodscrews, cap and set screws, machine screws, and tappingand drive screws in four separate documents, each ofwhich would consist of a complete product specification.This approach was confirmed by the B18 Committeewith the further stipulation that the coverage for hexa-gon head cap screws, square head set screws, andmachine screw nuts from the ASA B18.2 standard betransferred to the documents covering cap and setscrews and machine screws, respectively. It was under-stood that jurisdiction over the square head set screwsand hexagon head cap screws would remain with Sub-committee 2 and that Subcommittee 31 would retainresponsibility for machine screw nuts. Following thisconfirmation and additional direction, the preparationof proposals for the new documents was undertaken.

The proposed standard covering slotted and recessedhead machine screws and machine screw nuts wasapproved by Subcommittee 31 at a meeting held onDecember 6, 1955. After being circulated to industry forcomment, it was revised and subsequently approved byletter ballot of the B18 Committee in March of 1958.The proposal was, however, redrafted to incorporateadditional revisions and refinements adopted by Sub-committee 31 at meetings held on October 30, 1958 andSeptember 17, 1959. The revised proposal was recircu-lated to the B18 Committee and was approved by thesponsor organizations and the American StandardsAssociation and formally designated an American Stan-dard, ASA B18.6.3, on February 12, 1962.

Following issuance of the 1962 document, Subcommit-tee 31 and the working subgroups continued to developrevisions and refinements reflecting changes in industrypractices and technical improvements. Work over theintervening years culminated in the Subcommittee 6acceptance of a draft dated November 1969, incorporat-ing revisions in the following areas: inclusion of TypeIA cross recess data; addition of the No. 0000, 000, and00 sizes to most slotted head styles; extensions of size

vii

coverage for 100 deg flat countersunk heads and bindingheads in smaller sizes, and for pan heads in larger sizes;redimensioning of flat and oval countersunk heads; revi-sion of thread lengths; inclusion of appendices for wob-ble gaging of recessed heads and wrench sizes for squareand hex products; and a complete revamping of theformat.

This revision was approved as an American NationalStandard on May 22, 2003.

ASME B18 COMMITTEEStandardization of Bolts, Nuts, Rivets, Screws,

Washers, and Similar Fasteners(The following is the roster of the Committee at the time of approval of this Standard.)

OFFICERS

D. A. Clever, ChairR. D. Strong, Vice ChairS. W. Vass, Vice ChairR. L. Crane, Secretary

COMMITTEE PERSONNEL

J. Altman, Rotor Clip Co.J. H. Slass, Alternate, Rotor Clip Co.J. B. Belford, Lawson Products Inc.D. A. Clever, Deere and Co.A. P. Cockman, Ford Motor Co.T. Collier, Cam-Tech Industries Inc.R. L. Crane, The American Society of Mechanical EngineersA. C. DiCola, Wrought Washer Co.B. A. Dusina, Federal Screw WorksD. S. George, Ford Motor Co.D. L. Drobnich, Alternate, Ford Motor Co.J. Greenslade, Greenslade and Co.J. J. Grey, Fastener Consulting Services, Inc.B. Hasiuk, Defense Industrial Supply Center-PhiladelphiaA. Herskovitz, ConsultantJ. Hubbard, Rockford Fastener, Inc.J. F. Koehl, Spirol International Corp.W. H. Kopke, ITW Assembly ComponentsM. Levinson, Alternate, ITW ShakeproofJ. G. Langenstein, ConsultantL. L. Lord, Caterpillar Inc.W. J. Lutkus, Heli Coil EmhartA. D. McCrindle, Canadian Fasteners InstituteK. E. McCullough, ConsultantR. B. Meade, Textron Fastening SystemsM. D. Prasad, General Motors Corp.S. Savoji, ITW MedalistW. Schevey, BGM Fastener Co., Inc.R. D. Strong, General Motors Corp.S. W. Vass, Lake Erie Screw Corp.C. B. Wackrow, MNP Corp.R. G. Weber, Fairfield UniversityW. K. Wilcox, ConsultantC. J. Wilson, Industrial Fasteners InstituteR. B. Wright, Wright Tool Co.J. G. Zeratsky, National Rivet and Manufacturing Co.

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SUBCOMMITTEE 6 — SLOTTED AND RECESSED HEADSCREWS

R. D. Strong, Chair, General Motors Corp.R. L. Crane, Secretary, The American Society of Mechanical EngineersD. A. Clever, Deere and Co.M. Dailey, Barnes and Reinecke, Inc.D. L. Drobnich, Ford Motor Co.J. S. Foote, Trade Association Management, Inc.D. S. George, Ford Motor Co.J. Greenslade, Greenslade and Co.A. Herskovitz, ConsultantM. W. Holubecki, Electric Boat Corp.J. Hubbard, Rockford Fastener, Inc.M. Keller, ParaCAD Technology, Co.R. W. Kerr, Kerr Lakeside Inc.H. Lo, Defense Supply Center-PhiladelphiaS. Savoji, ITW MedalistG. M. Simpson, Semblex Corp.C. B. Wackrow, MNP Corp.W. K. Wilcox, ConsultantC. J. Wilson, Industrial Fasteners Institute

ix

CORRESPONDENCE WITH THE B18 COMMITTEE

General. ASME Standards are developed and maintained with the intent to represent theconsensus of concerned interests. As such, users of this Standard may interact with the Committeeby requesting interpretations, proposing revisions, and attending Committee meetings. Corre-spondence should be addressed to:

Secretary, B18 Standards CommitteeThe American Society of Mechanical EngineersThree Park AvenueNew York, NY 10016-5990

Proposing Revisions. Revisions are made periodically to the Standard to incorporate changesthat appear necessary or desirable, as demonstrated by the experience gained from the applicationof the Standard. Approved revisions will be published periodically.

The Committee welcomes proposals for revisions to this Standard. Such proposals should beas specific as possible, citing the paragraph number(s), the proposed wording, and a detaileddescription of the reasons for the proposal, including any pertinent documentation.

Interpretations. Upon request, the B18 Committee will render an interpretation of any require-ment of the Standard. Interpretations can only be rendered in response to a written request sentto the Secretary of the B18 Standards Committee.

The request for interpretation should be clear and unambiguous. It is further recommendedthat the inquirer submit his/her request in the following format:

Subject: Cite the applicable paragraph number(s) and the topic of the inquiry.Edition: Cite the applicable edition of the Standard for which the interpretation is

being requested.Question: Phrase the question as a request for an interpretation of a specific requirement

suitable for general understanding and use, not as a request for an approvalof a proprietary design or situation. The inquirer may also include any plansor drawings, which are necessary to explain the question; however, theyshould not contain proprietary names or information.

Requests that are not in this format may be rewritten in the appropriate format by the Committeeprior to being answered, which may inadvertently change the intent of the original request.

ASME procedures provide for reconsideration of any interpretation when or if additionalinformation that might affect an interpretation is available. Further, persons aggrieved by aninterpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not“approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity.

Attending Committee Meetings. The B18 Main Committee regularly holds meetings, which areopen to the public. Persons wishing to attend any meeting should contact the Secretary of theB18 Standards Committee.

x

ASME B18.6.3-2003

MACHINE SCREWS AND MACHINE SCREW NUTS

1 INTRODUCTORY NOTES

1.1 Scope

This Standard is intended to cover the complete gen-eral and dimensional data for the various types of slottedand recessed head machine screws and machine screwnuts recognized as American National Standard. Alsoincluded are appendices that provide specifications andinstructions for the protrusion gaging of flat count-ersunk head screws; across-corners gaging of hex headscrews; penetration gaging and wobble gaging ofrecessed head screws; wrench openings for hex andsquare products; thread dimensions for the No. 0000,No. 000, and No. 00 sizes; and formulas on which dimen-sional data are based. It shall be understood, however,that where questions arise concerning acceptance ofproduct, the dimensions in the tables shall govern overrecalculation by formula.

The inclusion of dimensional data in this Standard isnot intended to imply that all of the products describedare stock production sizes. Consumers should consultwith suppliers concerning the availability of products.

1.2 Machine Screw Head Types

The head types covered by this Standard include thosecommonly recognized as being applicable to machinescrews and are enumerated and described in the follow-ing paragraphs.

1.2.1 Flat Countersunk Head. The flat countersunkhead has a flat top surface and a conical bearing surfacewith a head angle for one style of approximately 82deg and for another style of approximately 100 deg.Dimensions are given in Tables 1A through 1E, and 2Athrough 2D, respectively. Dimensions of close tolerance100 deg flat countersunk heads are given in Tables 3Athrough 3D.

1.2.2 Oval Countersunk Head. The oval countersunkhead has a rounded top surface and a conical bearingsurface with a head angle of approximately 82 deg.Dimensions are given in Tables 4A through 4E.

1.2.3 Undercut Flat and Oval Countersunk Heads. Forshort lengths, 82 deg flat and oval countersunk headmachine screws have heads undercut to 70% of normalside height to afford greater length of thread on thescrews. Dimensions are given in Tables 5A through 5E,and 6A through 6E, respectively.

1

1.2.4 Flat and Oval Countersunk Trim Heads. Flat andoval countersunk trim heads are similar to the 82 degflat and oval countersunk heads except that the size ofhead for a given size screw is one or two sizes smallerthan the regular flat and oval countersunk head size,and oval countersunk trim heads have a controlledradius where the curved top surface meets the conicalbearing surface. Trim heads are furnished only in crossrecessed head types. Dimensions are given in Tables 7Athrough 7C, and 8A through 8C, respectively.

1.2.5 Pan Head. The slotted pan head has a flat topsurface rounded into cylindrical sides and a flat bearingsurface. The recessed pan head has a rounded top sur-face blending into cylindrical sides and a flat bearingsurface. Dimensions are given in Tables 9A through 9H.

1.2.6 Fillister Head. The fillister head has a roundedtop surface, cylindrical sides, and a flat bearing surface.Dimensions are given in Tables 10A through 10E.Dimensions of drilled fillister head machine screws aregiven in Table 11.

1.2.7 Truss Head. The truss head has a low roundedtop surface with a flat bearing surface, the diameter ofwhich for a given screw size is larger than the diameterof the corresponding pan head. Dimensions are givenin Tables 12A through 12G.

1.2.8 Binding Head. The binding head has a roundedtop surface and slightly tapered sides. The bearing sur-face is flat and, where so specified by purchaser, slottedheads shall have an annular undercut adjacent to theshank. Dimensions are given in Tables 13A through 13E.

1.2.9 Hex Head. The hex head has a flat or indentedtop surface, six flat sides, and a flat bearing surface.Dimensions for regular and large heads are given inTables 14A through 14C.

1.2.10 Hex Washer Head. The hex washer head has anindented top surface and six flat sides formed integrallywith a flat washer that projects beyond the sides andprovides a flat bearing surface. Dimensions are given inTables 15A through 15C.

1.2.11 Round Head. The round head has a semiellipti-cal top surface and a flat bearing surface. In recognitionof superior slot driving characteristics of pan headscrews over round head screws, and the overlap in thedimensions of cross recessed pan heads and roundheads, it is recommended that pan head screws be used

ASME B18.6.3-2003 MACHINE SCREWS AND MACHINE SCREW NUTS

in new designs and wherever possible substituted inexisting designs. To expedite elimination of the necessityfor perpetuating stocks of finished products and tooling,it should be recognized that during the transition periodmanufacturers may, when it is agreeable to users, substi-tute pan head where round head is specified. Dimen-sions of round head machine screws are given in Tables16A through 16G.

1.2.12 Round Washer Head. The round washer headhas a semielliptical top surface formed integrally witha flat washer that projects beyond the crown of the headand provides a flat bearing surface. Dimensions aregiven in Tables 17A and 17B.

1.3 Machine Screw Nuts

The machine screw nuts covered by this Standardinclude the hexagon and square varieties. Dimensionsare given in Table 18.

1.4 Dimensions

All dimensions in this Standard are given in inches,unless stated otherwise.

1.5 Options

Options, where specified, shall be at the discretion ofthe manufacturer unless otherwise agreed upon by themanufacturer and the purchaser.

1.6 Responsibility for Modification

The manufacturer shall not be held responsible formalfunctions of product determined to be due to platingor other modifications when such plating or modifica-tion is not accomplished under the manufacturer’s con-trol or direction.

1.7 Terminology

For definitions of terms relating to fasteners or fea-tures thereof used in this Standard, refer to ASME B18.12.

1.8 Related Standards

It should be noted that standards for cap screws, setscrews, tapping screws, wood screws, drive screws,sems, washers, and other related fasteners are publishedunder separate cover as listed at the end of this Standard.

1.9 Comparison With ISO

This Standard has no ISO counterpart.

1.10 Inspection and Quality Assurance

Unless otherwise specified, acceptability to this Stan-dard shall be determined in accordance with ASMEB18.18.1.

When applicable, the following designated character-istics shall be inspected to the inspection levels shownaccording to ASME B18.18.2 and shall be within theirspecified limits.

2

Designated Characteristic Inspection Level

Recess penetration depth CSlot depth CWidth across corners CThread acceptance CTensile strength test CNut proof load test C

If verifiable in-process inspection is used, inspectionsample sizes and reporting shall be in accordance withthe applicable ASME, ASTM, or SAE quality systemconsensus standard.

For nondesignated dimensional characteristics, theprovisions of ASME B18.18.1 shall apply. Should a non-designated dimension be determined to be outside itsspecified limits, it shall be deemed conforming to thisStandardif theuser whois the installer accepts the dimen-sion, based upon form, fit, and function considerations.

2 GENERAL DATA

2.1 Heads

2.1.1 Head Height. All dimensions pertaining to headheight specified in the dimensional tables shall be mea-sured parallel to the axis of screw and those relating tothe top of head shall represent a metal-to-metal measure-ment. In other words, any truncation of rounded headcontours due to the slot or recess shall not be consideredpart of the head height.

Total or overall head heights shall be measured fromthe top of the head to the plane of the bearing surfacefor flat bearing surface type heads, to the plane of theundercut for undercut countersunk heads, and to thejunction of the conical bearing surface with the basicscrew diameter for countersunk heads.

Head side heights shall be measured from the theoreti-cal intersection of the top surface of head with the headdiameter to the plane of the bearing surface for flatbearing surface type heads, to the plane of the undercutfor undercut countersunk heads, and to the junction ofthe conical bearing surface with the basic screw diameterfor countersunk heads.

On countersunk heads, the junction of the conicalbearing surface with the basic screw diameter may notnecessarily be the same as the actual junction of headwith shank and the head height delineating the conicalbearing surface is a reference dimension.

2.1.2 Bearing Surface. The bearing surface of flatbearing surface type machine screw heads shall be per-pendicular to the axis of the screw shanks within 2 deg.

2.1.3 Gaging of Recess. The penetration gagingdepth of the recess in recessed head screws shall be theprimary inspection criteria. It is measured, parallel tothe axis of screw, from the intersection of the maximumdiameter of the recess with the head surface to the pointat which penetration gage bottoms.

MACHINE SCREWS AND MACHINE SCREW NUTS ASME B18.6.3-2003

Recess gaging values are included in the respectivedimensional tables, including the reference dimensionsof recess diameter, wing width, and total recess depth.The gaging method and specifications for gages are con-tained in Appendix III.

Recess wobble gages, gaging procedures, and permis-sible limits are given in Appendix IV.

2.1.4 Slot. The depth of the slot in slotted head screwsshall be measured, parallel to the axis of screw, from thetop of the head to the intersection of the bottom of theslot with the head surface or bearing surface.

The width of the slot shall be measured perpendicularto the axis of the screw, from the theoretical intersectionof the bottom and one side of the slot, to the theoreticalintersection of the bottom and the other side of the slot.

Unless specified by the purchaser, the slot width maybe slightly tapered from the bottom to the top, orstraight, at the option of the manufacturer.

2.1.5 Feature Positional Tolerances. The positionalrelationship of the heads and driving provisions ofscrews with respect to the shanks of screws (formerlydefined as eccentricity) shall be as follows.

(a) True Position of Head. The axis of the head shall belocated at true position relative to the axis of the screwshank within a tolerance zone having a diameter equiva-lent to 6% of the specified maximum head diameter, ormaximum width across flats of hex and hex washerheads, regardless of feature size.

(b) True Position of Recess. The recess in cross recessedhead screws shall be located at true position relative tothe axis of the screw shank within a tolerance zonehaving a diameter equivalent to 12% of the basic screwdiameter or 0.030 in., whichever is greater, regardlessof feature size.

(c) True Position of Slot. The slot in slotted head screwsshall be located at true position relative to the axis of thescrew shank within a tolerance zone having a diameterequivalent to 12% of the basic screw diameter or 0.020in., whichever is greater.

2.1.6 Underhead Fillets. Machine screws shall havea definite underhead fillet large enough to ensure thatfull fastener strength is achieved. The radius of the filletunder countersunk head screws shall be no greater than40% of the basic screw diameter. The radius of the filletunder truss heads and number 6 sized pan heads shallbe no greater than 25% of the basic screw diameter. Theradius of the fillet under all other head styles shall beno greater than 15% of the basic screw diameter.

2.2 Length

2.2.1 Measurement. The nominal length of screw Lshall be measured, parallel to the axis of screw, from theextreme point to the plane of the bearing surface forscrews having perpendicular bearing surface type heads,and to the theoretical intersection of the top surface of

3

head with the head diameter for screws having count-ersunk type heads. For all oval heads, the overall lengthLo shall be measured, parallel to the axis of the screw, fromthe extreme point to the top of the head, where:

Lo p L + C

2.2.2 Tolerance on Length. The length tolerance shallapply to Lo for all oval heads and to L for all other headstyles. The tolerance on the length of machine screwsshall conform to the following for the respective screwtypes:

Tolerance on Lengthfor Nominal Screw Size

Nominal 0000 0 1⁄4Screw Through Through ThroughLength 00 12 3⁄4

Up to 1⁄2 in., incl. −0.01 −0.02 −0.03Over 1⁄2 to 1 in., incl. −0.02 −0.03 −0.03Over 1 to 2 in., incl. . . . −0.06 −0.06Over 2 in. . . . −0.09 −0.09

2.3 Threads

2.3.1 Machine Screws. The threads on machinescrews, except for the No. 0000, No. 000, and No. 00sizes, which are covered in Appendix V, shall be UnifiedStandard, Class 2A, UNC and UNF series, or UNRCand UNRF series, at option of manufacturer, in accor-dance with ASME B1.1. For threads with additive finish,the maximum diameters of Class 2A may be exceededby the amount of the allowance; that is, the Class 2Amaximum diameters shall apply to an unplated oruncoated part, or to a part before plating or coating,whereas the basic diameters (Class 3A GO) shall applyto a part after plating or coating. The minimum majordiameter of plated or coated screws may approach butshall not be less than the Class 2A minimum limit.

2.3.2 Machine Screw Nuts. Threads shall be UnifiedStandard, Class 2B, UNC or UNF series for hexagonmachine screw nuts, and UNC series for square machinescrew nuts, in accordance with ASME B1.1.

2.4 Length of Thread

2.4.1 Machine Screws. Machine screws shall havethread lengths conforming to the following (on screwsthreaded full length, the distance to first full form threadshall be measured, parallel to the axis of screw, fromthe bearing surface of the head to the face of a noncham-fered or noncounterbored standard 3A GO thread ringgage assembled by hand as far as the thread will permit).

(a) Sizes No. 5 and Smaller. Screws of nominal lengthsequal to three diameters and shorter shall have full formthreads extending to within one pitch (thread) of thebearing surface of the head, or closer, if practicable.Nominal lengths greater than three diameters, up to andincluding 11⁄8 in., shall have full form threads extendingto within two pitches (threads) of the bearing surface


of the head, or closer, if practicable. Screws of longernominal lengths shall, unless otherwise specified, havea minimum length of full form thread of 1 in.

(b) Sizes No. 6 and Larger. Screws of nominal lengthsequal to three diameters and shorter shall have full formthreads extending to within one pitch (thread) of thebearing surface of the head, or closer, if practicable.Nominal lengths greater than three diameters, up to andincluding 2 in., shall have full form threads extendingto within two pitches (threads) of the bearing surfaceof the head, or closer, if practicable. Screws of longernominal lengths shall, unless otherwise specified, havea minimum length of full form thread of 1.50 in.

2.5 Points

Unless otherwise specified, machine screws shall haveplain sheared ends. Where so specified, header pointsshall be as shown in Table 19. Other points or pointing oflonger lengths to header point dimensions may requiremachining.

2.6 Diameter of Body

2.6.1 Machine Screws. The diameter of body onmachine screws having other than trim heads shall notbe less than the Class 2A thread minimum pitch diame-ter nor greater than the basic major diameter of thethread.

2.6.2 Trim Head Machine Screws. The diameter ofbody on trim head machine screws shall not be less thanthe Class 2A thread minimum pitch diameter nor greaterthan the basic major diameter of the thread. Screws notthreaded to the head shall have a 0.062 in., minimumlength shoulder under the head with diameter limits asspecified in the dimensional tables.

2.7 Material

2.7.1 Machine Screws. Unless otherwise specified,machine screws shall be fabricated from carbon steeland shall have a minimum tensile strength of 60,000 psi.

Machine screws, where so specified, may also be madefrom higher strength steels, corrosion resistant steel,brass, monel, aluminum alloys, or other materials, asagreed upon between the manufacturer and the pur-chaser.

2.7.2 Machine Screw Nuts. Machine screw nuts arenormally supplied in steel, corrosion resistant steel, orbrass as specified by the purchaser. Unless otherwisespecified, no physical requirements shall apply.

2.8 Finish

Unless otherwise specified, machine screws andmachine screw nuts shall be supplied with a natural (asprocessed) finish, unplated or uncoated.

4

2.9 Workmanship

Machine screws and machine screw nuts shall notcontain an excess of surface imperfections that mightaffect their serviceability, such as, burrs, seams, laps,loose scale, and other irregularities.

2.10 Designation

2.10.1 Machine Screws(a) Machine screws shall be designated by the follow-

ing data preferably in the sequence shown: productname including head type and driving provision anddesignation of the standard, nominal size (number, frac-tion, or decimal equivalent); threads per inch; nominallength (fraction or decimal equivalent); header point, ifdesired, material, protective coating, if required.

EXAMPLES:(1) Slotted Pan Head Machine Screws, ASME B18.6.3, 1⁄4 − 20 �

11⁄4, Carbon Steel, Zinc Plated per ASTM F 1941 Fe/Zn 5C.(2) Type IA Cross Recessed Fillister Head Machine Screw, ASME

B18.6.3, 6 − 32 � 3⁄4, Brass per ASTM B 21 UNS C46200.(3) Hexagon Washer Head Machine Screw, ASME B18.6.3, 0.375

− 16 � 1.50, Header Point, Carbon Steel.(4) Type II Cross Recessed Flat Countersunk Head Machine Screw,

ASME B18.6.3, 0.190 − 24 � 1.50, Carbon Steel, Phosphate/Oil per ASTM F 1137 Grade 0D.

(b) For a recommended part identifying number(PIN) system for machine screws, see ASME B18.24.

2.10.2 Machine Screws Nuts(a) Machine screws nuts shall be designated by the

following data preferably in the sequence shown: prod-uct name and designation of the standard, nominal size(number, fraction, or decimal equivalent); threads perinch, material, protective coating, if required.

EXAMPLES:(1) Hexagon Machine Screw Nut, ASME B18.6.3, 10 − 24, Steel,

Zinc Plated per ASTM F 1941 Fe/Zn 5C.(2) Square Machine Screw Nut, ASME B18.6.3, 0.138 − 32, Brass

per ASTM B 21 UNS C46200.

(b) For a recommended part identifying number(PIN) system for machine screw nuts, see ASME B18.24.

3 REFERENCES

Unless otherwise specified, the standards referencedshall be the most recent at the time of order placement.

ASME B1.1, Unified Inch Screw Threads (UN and UNRThread Form)

ASME B18.12, Glossary of Terms for Mechanical Fas-teners


ASME B18.18.1, Inspection and Quality Assurance forGeneral Purpose Fasteners

ASME B18.18.2, Inspection and Quality Assurance forHigh-Volume Machine Assembly Fasteners

ASME B18.24, Part Identifying Number (PIN) Code Sys-tem for B18 Fastener Products

Publisher: The American Society of Mechanical Engi-neers (ASME International), Three Park Avenue, NewYork, NY 10016-5990; Order Department: 22 LawDrive, Box 2300, Fairfield, NJ 07007-2300

5

ASTM B 21, Specification for Naval Brass, Rod, Bar, andShapes

ASTM F 1137, Specification for Phosphate/Oil andPhosphate/Organic Corrosion Protective Coatings forFasteners

ASTM F 1941, Specification for Electrodeposited Coat-ings on Threaded Fasteners [Unified Inch ScrewThreads (UN/UNR)]

Publisher: American Society for Testing and Materials(ASTM), 100 Barr Harbor Drive, West Conshohocken,PA 19428


Table 1A Dimensions of Slotted Flat Countersunk Head Machine ScrewsProtrusion Above GagingNominal Size or Head Gaging

Head Diameter, Slot Width, Slot Depth, Diameter,Basic Screw Length, Height, Diameter,A J T F [Note (4)]Diameter L H, Ref. G

[Note (1)] [Note (2)] Max. Min. [Note (3)] Max. Min. Max. Min. Max. Min. [Note (4)]

0000 0.0210 . . . 0.040 0.035 0.011 0.008 0.004 0.007 0.003 [Note (5)] [Note (5)] [Note (5)]000 0.0340 . . . 0.060 0.055 0.016 0.011 0.007 0.009 0.005 [Note (5)] [Note (5)] [Note (5)]

00 0.0470 . . . 0.087 0.080 0.028 0.017 0.010 0.014 0.009 [Note (5)] [Note (5)] [Note (5)]

0 0.0600 1⁄8 0.112 0.096 0.035 0.023 0.016 0.015 0.010 0.026 0.016 0.0781 0.0730 1⁄8 0.137 0.120 0.043 0.026 0.019 0.019 0.012 0.028 0.016 0.1012 0.0860 1⁄8 0.162 0.144 0.051 0.031 0.023 0.023 0.015 0.029 0.017 0.1243 0.0990 1⁄8 0.187 0.167 0.059 0.035 0.027 0.027 0.017 0.031 0.018 0.148

4 0.1120 3⁄16 0.212 0.191 0.067 0.039 0.031 0.030 0.020 0.032 0.019 0.1725 0.1250 3⁄16 0.237 0.215 0.075 0.043 0.035 0.034 0.022 0.034 0.020 0.1966 0.1380 3⁄16 0.262 0.238 0.083 0.048 0.039 0.038 0.024 0.036 0.021 0.220

8 0.1640 1⁄4 0.312 0.285 0.100 0.054 0.045 0.045 0.029 0.039 0.023 0.26710 0.1900 5⁄16 0.362 0.333 0.116 0.060 0.050 0.053 0.034 0.042 0.025 0.31312 0.2160 3⁄8 0.412 0.380 0.132 0.067 0.056 0.060 0.039 0.045 0.027 0.362

1⁄4 0.25007⁄16 0.477 0.442 0.153 0.075 0.064 0.070 0.046 0.050 0.029 0.424

5⁄16 0.31251⁄2 0.597 0.556 0.191 0.084 0.072 0.088 0.058 0.057 0.034 0.539

3⁄8 0.37509⁄16 0.717 0.670 0.230 0.094 0.081 0.106 0.070 0.065 0.039 0.653

7⁄16 0.43755⁄8 0.760 0.715 0.223 0.094 0.081 0.103 0.066 0.073 0.044 0.690

1⁄2 0.50003⁄4 0.815 0.765 0.223 0.106 0.091 0.103 0.065 0.081 0.049 0.739

9⁄16 0.5625 . . . 0.932 0.878 0.260 0.118 0.102 0.120 0.077 0.089 0.053 0.8515⁄8 0.6250 . . . 1.050 0.990 0.298 0.133 0.116 0.137 0.088 0.097 0.058 0.9623⁄4 0.7500 . . . 1.285 1.215 0.372 0.149 0.131 0.171 0.111 0.112 0.067 1.186

GENERAL NOTE: For additional requirements, refer to para. 2.

NOTES:(1) Where specifying nominal size in decimals, zeros preceding the decimal and in the fourth decimal place shall be

omitted.(2) Screws of these lengths and shorter shall have undercut heads as shown in Table 5A.(3) Tabulated values determined from formula for maximum H in Appendix A.(4) No tolerance for gaging diameter is given. If the gaging diameter of the gage used differs from tabulated value, the pro-

trusion will be affected accordingly and the proper protrusion values must be recalculated using the formulas shown inAppendix I.

(5) Not practical to gage.

6


Table 1B Dimensions of Type I Cross Recessed Flat Countersunk Head Machine Screws

RecessHead Penetration Protrusion AboveNominal Size Head Gaging

Diameter, Gaging Gaging Diameter,or Basic Screw Length, Height, Recess Recess Recess Diameter,A Depth F [Note (4)]Diameter L H, Ref. Diameter, Depth, Width, Driver G

[Note (1)] [Note (2)] Max. Min. [Note (3)] M, Ref. T, Ref. N, Ref. Size Max. Min. Max. Min. [Note (4)]

0 0.0600 1⁄8 0.112 0.096 0.035 0.062 0.035 0.014 0 0.036 0.020 0.026 0.016 0.0781 0.0730 1⁄8 0.137 0.120 0.043 0.070 0.043 0.015 0 0.044 0.028 0.028 0.016 0.1012 0.0860 1⁄8 0.162 0.144 0.051 0.096 0.055 0.017 1 0.056 0.040 0.029 0.017 0.1243 0.0990 1⁄8 0.187 0.167 0.059 0.100 0.060 0.018 1 0.061 0.045 0.031 0.018 0.148

4 0.1120 3⁄16 0.212 0.191 0.067 0.122 0.081 0.018 1 0.082 0.066 0.032 0.019 0.1725 0.1250 3⁄16 0.237 0.215 0.075 0.148 0.074 0.027 2 0.075 0.052 0.034 0.020 0.1966 0.1380 3⁄16 0.262 0.238 0.083 0.168 0.094 0.029 2 0.095 0.072 0.036 0.021 0.220

8 0.1640 1⁄4 0.312 0.285 0.100 0.182 0.110 0.030 2 0.110 0.087 0.039 0.023 0.26710 0.1900 5⁄16 0.362 0.333 0.116 0.198 0.124 0.032 2 0.125 0.102 0.042 0.025 0.31312 0.2160 3⁄8 0.412 0.380 0.132 0.262 0.144 0.035 3 0.139 0.116 0.045 0.027 0.362

1⁄4 0.25007⁄16 0.477 0.442 0.153 0.276 0.160 0.036 3 0.154 0.131 0.050 0.029 0.424

5⁄16 0.31251⁄2 0.597 0.556 0.191 0.358 0.205 0.061 4 0.196 0.174 0.057 0.034 0.539

3⁄8 0.37509⁄16 0.717 0.670 0.230 0.386 0.234 0.065 4 0.225 0.203 0.065 0.039 0.653

7⁄16 0.43755⁄8 0.760 0.715 0.223 0.402 0.250 0.068 4 0.241 0.219 0.073 0.044 0.690

1⁄2 0.50003⁄4 0.815 0.765 0.223 0.418 0.265 0.069 4 0.256 0.234 0.081 0.049 0.739

9⁄16 0.5625 . . . 0.932 0.878 0.260 0.443 0.289 0.073 4 0.280 0.258 0.089 0.053 0.8515⁄8 0.6250 . . . 1.050 0.990 0.298 0.565 0.329 0.079 5 0.309 0.283 0.097 0.058 0.9623⁄4 0.7500 . . . 1.285 1.215 0.372 0.628 0.393 0.087 5 0.373 0.347 0.112 0.067 1.186



omitted.(2) Screws of these lengths and shorter shall have undercut heads as shown in Table 5B.(3) Tabulated values determined from formula for maximum H in Appendix A.(4) No tolerance for gaging diameter is given. If the gaging diameter of the gage used differs from tabulated value, the pro-


7


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0.03

50.

062

0.03

60.

018

00.

037

0.02

10.

026

0.01

60.

078

10.

0730

1 ⁄8

0.13

70.

120

0.04

30.

070

0.04

40.

018

00.

045

0.02

90.

028

0.01

60.

101

20.

0860

1 ⁄8

0.16

20.

144

0.05

10.

096

0.05

50.

029

10.

053

0.03

70.

029

0.01

70.

124

30.

0990

1 ⁄8

0.18

70.

167

0.05

90.

100

0.06

00.

029

10.

058

0.04

20.

031

0.01

80.

148

40.

1120

3 ⁄16

0.21

20.

191

0.06

70.

122

0.08

10.

030

10.

079

0.06

30.

032

0.01

90.

172

50.

1250

3 ⁄16

0.23

70.

215

0.07

50.

148

0.07

70.

041

20.

071

0.05

30.

034

0.02

00.

196

60.

1380

3 ⁄16

0.26

20.

238

0.08

30.

168

0.09

80.

041

20.

091

0.07

30.

036

0.02

10.

220

80.

1640

1 ⁄4

0.31

20.

285

0.10

00.

182

0.11

20.

041

20.

107

0.08

90.

039

0.02

30.

267

100.

1900

5 ⁄16

0.36

20.

333

0.11

60.

198

0.12

70.

041

20.

122

0.10

40.

042

0.02

50.

313

120.

2160

3 ⁄8

0.41

20.

380

0.13

20.

262

0.14

90.

056

30.

136

0.11

80.

045

0.02

70.

362

1 ⁄4

0.25

007 ⁄

160.

477

0.44

20.

153

0.27

60.

164

0.05

73

0.15

10.

133

0.05

00.

029

0.42

45 ⁄

160.

3125

1 ⁄2

0.59

70.

556

0.19

10.

358

0.21

10.

086

40.

193

0.17

50.

057

0.03

40.

539

3 ⁄8

0.37

509 ⁄

160.

717

0.67

00.

230

0.38

60.

239

0.08

64

0.22

20.

204

0.06

50.

039

0.65

37 ⁄

160.

4375

5 ⁄8

0.76

00.

715

0.22

30.

402

0.25

60.

086

40.

238

0.22

00.

073

0.04

40.

690

1 ⁄2

0.50

003 ⁄

40.

815

0.76

50.

223

0.41

80.

271

0.08

64

0.25

30.

235

0.08

10.

049

0.73

99 ⁄

160.

5625

...

0.93

20.

878

0.26

00.

440

0.29

40.

087

40.

276

0.25

80.

089

0.05

30.

851

5 ⁄8

0.62

50..

.1.

050

0.99

00.

298

0.56

60.

334

0.09

85

0.30

70.

286

0.09

70.

058

0.96

23 ⁄

40.

7500

...

1.28

51.

215

0.37

20.

630

0.40

00.

099

50.

372

0.35

10.

112

0.06

71.

186

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ERA

LN

OTE

:Fo

rad

diti

onal

requ

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fer

topa

ra.

2.

NO

TES:

(1)

Whe

resp

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nom

inal

size

inde

cim

als,

zero

spr

eced

ing

the

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mal

and

inth

efo

urth

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plac

esh

all

beom

itte

d.(2

)Sc

rew

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thes

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all

have

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head

sas

show

nin

Tabl

e5C

.(3

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oto

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ers

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form

ulas

show

nin

App

endi

xI.

8


Pro

tru

sio

n g

age

L

A G

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A m

in.

H

MN

T

Th

is t

ype

of

rece

ss c

on

sist

s o

f tw

o

inte

rsec

tin

g s

lots

wit

h p

aral

lel

si

des

co

nve

rgin

g t

o a

slig

htl

y

tru

nca

ted

ap

ex a

t b

ott

om

of

rece

ss.

82�

80�

Ed

ge

of

hea

d m

ay

be

rou

nd

ed o

r fl

at

Tabl

e1D

Dim

ensi

ons

ofTy

peII

Cros

sRe

cess

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atCo

unte

rsun

kH

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Mac

hine

Scre

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Prot

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onH

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Abo

veG

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eter

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cess

Pene

trat

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met

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orB

asic

Scr

ewLe

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eigh

t,Re

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ssRe

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Dri

ver

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met

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AG

agin

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epth

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ote

(5)]

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met

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[Not

e(1

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(2)]

Max

.M

in.

[Not

e(3

)]M

,Re

f.T,

Ref.

N,

Ref.

[Not

e(4

)]M

ax.

Min

.M

ax.

Min

.[N

ote

(5)]

00.

0600

1 ⁄8

0.11

20.

096

0.03

50.

078

0.03

60.

021

...

[Not

e(6

)][N

ote

(6)]

0.02

60.

016

0.07

81

0.07

301 ⁄

80.

137

0.12

00.

043

0.09

20.

048

0.02

4..

.[N

ote

(6)]

[Not

e(6

)]0.

028

0.01

60.

101

20.

0860

1 ⁄8

0.16

20.

144

0.05

10.

114

0.06

00.

027

...

0.04

00.

029

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90.

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43

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901 ⁄

80.

187

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70.

059

0.13

30.

072

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0..

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053

0.04

10.

031

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80.

148

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1120

3 ⁄16

0.21

20.

191

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70.

151

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20.

032

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0.06

40.

052

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20.

019

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25

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503 ⁄

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237

0.21

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075

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90.

094

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077

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40.

034

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00.

196

60.

1380

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20.

238

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188

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038

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401 ⁄

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312

0.28

50.

100

0.22

40.

124

0.04

3..

.0.

113

0.09

90.

039

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30.

267

100.

1900

5 ⁄16

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20.

333

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60.

260

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80.

048

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0.13

70.

122

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025

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132

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70.

172

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4..

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162

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50.

045

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70.

362

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477

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153

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195

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1..

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193

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050

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191

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20.

252

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4..

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251

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057

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760

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223

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332

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2..

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332

0.31

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003 ⁄

40.

815

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223

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rad

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onal

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ra.

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TES

:(1

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here

spec

ifyi

ngno

min

alsi

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mal

s,ze

ros

prec

edin

gth

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cim

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four

thde

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omit

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s.(5

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nce

for

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give

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gagi

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used

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ers

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late

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lue,

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onw

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cted

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rdin

gly

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ing

the

form

ulas

show

nin

App

endi

xI.

(6)

Not

prac

tica

lto

gage

.

9


Pro

tru

sio

n g

age

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F

H

M

T P

Th

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ype

of

rece

ss h

as a

sq

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ter

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alls

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d a

co

nic

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ott

om

,

wit

h t

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un

ded

.

82�

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of

hea

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ay

be

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nd

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r fl

at

Tabl

e1E

Dim

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ons

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Squa

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ead

Mac

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Scre

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Hea

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Nom

inal

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ead

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epth

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ote

(1)]

[Not

e(2

)]M

ax.

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.[N

ote

(3)]

M,

Ref.

T,Re

f.[N

ote

(4)]

Max

.M

in.

Max

.M

in.

[Not

e(6

)]

20.

0860

1 ⁄8

0.16

20.

144

0.05

10.

050

0.05

700

0.03

30.

028

0.02

90.

017

0.12

43

0.09

901 ⁄

80.

187

0.16

70.

059

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00.

066

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038

0.02

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031

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80.

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40.

1120

3 ⁄16

0.21

20.

191

0.06

70.

070

0.06

60

0.03

80.

028

0.03

20.

019

0.17

2

50.

1250

3 ⁄16

0.23

70.

215

0.07

50.

091

0.09

61S

0.05

50.

040

0.03

40.

020

0.19

66

0.13

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160.

262

0.23

80.

083

0.09

10.

096

1S0.

055

0.04

00.

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0.02

10.

220

80.

1640

1 ⁄4

0.31

20.

285

0.10

00.

112

0.11

52S

0.06

30.

048

0.03

90.

023

0.26

710

0.19

005 ⁄

160.

362

0.33

30.

116

0.11

20.

127

2R0.

075

0.06

00.

042

0.02

50.

313

120.

2160

3 ⁄8

0.41

20.

380

0.13

20.

133

0.15

83R

0.09

50.

080

0.04

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027

0.36

21 ⁄

40.

2500

7 ⁄16

0.47

70.

442

0.15

30.

133

0.15

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00.

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0.42

45 ⁄

160.

3125

1 ⁄2

0.59

70.

556

0.19

10.

191

0.19

44R

0.10

00.

085

0.05

70.

034

0.53

93 ⁄

80.

3750

9 ⁄16

0.71

70.

670

0.23

00.

191

0.19

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0.10

00.

085

0.06

50.

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0.65

3

GEN

ERA

LN

OTE

:Fo

rad

diti

onal

requ

irem

ents

,re

fer

topa

ra.

2.

NO

TES

:(1

)W

here

spec

ifyi

ngno

min

alsi

zein

deci

mal

s,ze

ros

prec

edin

gth

ede

cim

alan

din

the

four

thde

cim

alpl

ace

shal

lbe

omit

ted.

(2)

Scr

ews

ofth

ese

leng

ths

and

shor

ter

shal

lha

veun

derc

uthe

ads

assh

own

inTa

ble

5E.

(3)

Tabu

late

dva

lues

dete

rmin

edfr

omfo

rmul

afo

rm

axim

umH

inA

ppen

dix

A.

(4)

“R”

inth

ere

cess

size

tabu

lati

onm

eans

regu

lar

dept

hre

cess

,an

dth

e“S

”m

eans

shor

tde

pth

rece

ss.

(5)

Squ

are

rece

sses

inco

rpor

ate

asl

ight

tape

ron

the

side

sof

the

rece

ss.

This

tape

rca

nre

sult

inlo

ssof

pene

trat

ion

gagi

ngde

pth

onfin

ishe

dfa

sten

ers

due

toth

ebu

ildup

ofpl

atin

gin

the

rece

sses

.Th

ere

cess

pene

trat

ion

dim

ensi

ons

spec

ified

here

are

for

finis

hed

(pla

ted)

prod

uct.

Man

ufac

ture

rssh

ould

bead

vise

dth

atth

eysh

ould

not

use

all

this

tole

ranc

ein

the

head

ing

proc

ess,

oran

out

ofto

lera

nce

cond

itio

nco

uld

exis

taf

ter

plat

ing.

(6)

No

tole

ranc

efo

rga

ging

diam

eter

isgi

ven.

Ifth

ega

ging

diam

eter

ofth

ega

geus

eddi

ffer

sfr

omta

bula

ted

valu

e,th

epr

otru

sion

will

beaf

fect

edac

cord

ingl

yan

dth

epr

oper

prot

rusi

onva

lues

mus

tbe

reca

lcul

ated

usin

gth

efo

rmul

assh

own

inA

ppen

dix

I.

10


Table 2A Dimensions of Slotted 100 deg Flat Countersunk Head Machine Screws

NominalHead Slot SlotSize or Head Gaging

Diameter, Width, Depth, Protrusion Above GagingBasic Screw Height, Diameter,A J T Diameter, F [Note (3)]Diameter H, Ref. G

[Note (1)] Max. Min. [Note (2)] Max. Min. Max. Min. Max. Min. [Note (3)]

0000 0.0210 0.040 0.035 0.009 0.008 0.005 0.008 0.004 [Note (4)] [Note (4)] [Note (4)]000 0.0340 0.060 0.055 0.014 0.012 0.008 0.011 0.007 [Note (4)] [Note (4)] [Note (4)]

00 0.0470 0.087 0.080 0.020 0.017 0.010 0.013 0.008 [Note (4)] [Note (4)] [Note (4)]

0 0.0600 0.112 0.095 0.026 0.023 0.016 0.013 0.008 0.020 0.012 0.0741 0.0730 0.137 0.118 0.031 0.026 0.019 0.016 0.010 0.021 0.013 0.0982 0.0860 0.162 0.142 0.037 0.031 0.023 0.019 0.012 0.022 0.014 0.1213 0.0990 0.187 0.165 0.043 0.035 0.027 0.022 0.014 0.024 0.015 0.144

4 0.1120 0.212 0.188 0.049 0.039 0.031 0.024 0.017 0.025 0.016 0.1676 0.1380 0.262 0.235 0.060 0.048 0.039 0.030 0.022 0.028 0.017 0.2148 0.1640 0.312 0.282 0.072 0.054 0.045 0.036 0.027 0.031 0.019 0.261

10 0.1900 0.362 0.329 0.083 0.060 0.050 0.042 0.031 0.034 0.021 0.3071⁄4 0.2500 0.477 0.437 0.110 0.075 0.064 0.055 0.042 0.040 0.025 0.415

5⁄16 0.3125 0.597 0.550 0.138 0.084 0.072 0.069 0.053 0.047 0.030 0.5263⁄8 0.3750 0.717 0.662 0.165 0.094 0.081 0.083 0.065 0.053 0.034 0.638



omitted.(2) Tabulated values determined from formula for maximum H in Appendix A.(3) No tolerance for gaging diameter is given. If the gaging diameter of the gage used differs from tabulated value, the pro-



11


Table 2B Dimensions of Type I Cross Recessed 100 deg Flat Countersunk HeadMachine Screws

Protrusion AboveNominalHead Gaging Diameter,Size or Head Gaging

Diameter, Recess Penetration FBasic Screw Height, Recess Recess Recess Diameter,A Gaging Depth [Note (3)]Diameter H, Ref. Diameter, Depth, Width, Driver G

[Note (1)] Max. Min. [Note (2)] M, Ref. T, Ref. N, Ref. Size Max. Min. Max. Min. [Note (3)]

0 0.0600 0.112 0.095 0.026 0.054 0.027 0.013 0 0.028 0.012 0.020 0.012 0.0741 0.0730 0.137 0.118 0.031 0.062 0.035 0.014 0 0.036 0.020 0.021 0.013 0.0982 0.0860 0.162 0.142 0.037 0.088 0.048 0.012 1 0.049 0.033 0.022 0.014 0.1213 0.0990 0.187 0.165 0.043 0.096 0.055 0.014 1 0.056 0.040 0.024 0.015 0.144

4 0.1120 0.212 0.188 0.049 0.110 0.070 0.018 1 0.071 0.055 0.025 0.016 0.1676 0.1380 0.262 0.235 0.060 0.148 0.074 0.027 2 0.075 0.052 0.028 0.017 0.2148 0.1640 0.312 0.282 0.072 0.162 0.090 0.028 2 0.090 0.067 0.031 0.019 0.261

10 0.1900 0.362 0.329 0.083 0.178 0.104 0.030 2 0.105 0.082 0.034 0.021 0.307

1⁄4 0.2500 0.477 0.437 0.110 0.240 0.124 0.033 3 0.118 0.095 0.040 0.025 0.4155⁄16 0.3125 0.597 0.550 0.138 0.310 0.157 0.053 4 0.148 0.126 0.047 0.030 0.5263⁄8 0.3750 0.717 0.662 0.165 0.336 0.182 0.056 4 0.173 0.151 0.053 0.034 0.638





12


Table 2C Dimensions of Type IA Cross Recessed 100 deg Flat Countersunk HeadMachine Screws

NominalSize or

Head Recess Protrusion AboveBasic Head GagingDiameter, Penetration Gaging Diameter,Screw Height, Recess Recess Recess Diameter,

A Gaging Depth F [Note (3)]Diameter H, Ref. Diameter, Depth, Width, Driver G[Note (1)] Max. Min. [Note (2)] M, Ref. T, Ref. N, Ref. Size Max. Min. Max. Min. [Note (3)]

0 0.0600 0.112 0.095 0.026 0.054 0.028 0.018 0 0.029 0.013 0.020 0.012 0.0741 0.0730 0.137 0.118 0.031 0.062 0.036 0.018 0 0.037 0.021 0.021 0.013 0.0982 0.0860 0.162 0.142 0.037 0.088 0.048 0.028 1 0.046 0.030 0.022 0.014 0.1213 0.0990 0.187 0.165 0.043 0.096 0.055 0.029 1 0.053 0.037 0.024 0.015 0.144

4 0.1120 0.212 0.188 0.049 0.110 0.070 0.029 1 0.068 0.052 0.025 0.016 0.1676 0.1380 0.262 0.235 0.060 0.148 0.077 0.041 2 0.071 0.053 0.028 0.017 0.2148 0.1640 0.312 0.282 0.072 0.162 0.092 0.041 2 0.086 0.068 0.031 0.019 0.261

10 0.1900 0.362 0.329 0.083 0.178 0.107 0.041 2 0.101 0.083 0.034 0.021 0.307

1⁄4 0.2500 0.477 0.437 0.110 0.240 0.126 0.056 3 0.114 0.096 0.040 0.025 0.4155⁄16 0.3125 0.597 0.550 0.138 0.310 0.163 0.085 4 0.145 0.127 0.047 0.030 0.526

3⁄8 0.3750 0.717 0.662 0.165 0.336 0.187 0.085 4 0.170 0.152 0.053 0.034 0.638





13


Table 2D Dimensions of Type II Cross Recessed 100 deg Flat Countersunk HeadMachine Screws

NominalProtrusionSize or

Head Above GagingBasic Head GagingDiameter, Recess Penetration Diameter, F,Screw Height, Recess Recess Recess Driver Diameter,

A Gaging Depth [Note (4)]Diameter H, Ref. Diameter, Depth, Width, Size G[Note (1)] Max. Min. [Note (2)] M, Ref. T, Ref. N, Ref. [Note (3)] Max. Min. Max. Min. [Note (4)]

0 0.0600 0.112 0.095 0.026 0.057 0.026 0.020 . . . [Note (5)] [Note (5)] 0.020 0.012 0.0741 0.0730 0.137 0.118 0.031 0.078 0.040 0.023 . . . [Note (5)] [Note (5)] 0.021 0.013 0.0982 0.0860 0.162 0.142 0.037 0.092 0.048 0.025 . . . 0.025 0.015 0.022 0.014 0.1213 0.0990 0.187 0.165 0.043 0.113 0.061 0.027 . . . 0.039 0.028 0.024 0.015 0.144

4 0.1120 0.212 0.188 0.049 0.131 0.070 0.029 . . . 0.051 0.036 0.025 0.016 0.1676 0.1380 0.262 0.235 0.060 0.157 0.086 0.033 . . . 0.068 0.051 0.028 0.017 0.2148 0.1640 0.312 0.282 0.072 0.185 0.102 0.037 . . . 0.086 0.067 0.031 0.019 0.261

10 0.1900 0.362 0.329 0.083 0.219 0.122 0.042 . . . 0.109 0.087 0.034 0.021 0.307

1⁄4 0.2500 0.477 0.437 0.110 0.288 0.164 0.053 . . . 0.154 0.132 0.040 0.025 0.4155⁄16 0.3125 0.597 0.550 0.138 0.355 0.207 0.063 . . . 0.197 0.175 0.047 0.030 0.526

3⁄8 0.3750 0.717 0.662 0.165 0.433 0.258 0.075 . . . 0.249 0.226 0.053 0.034 0.638



omitted.(2) Tabulated values determined from formula for maximum H in Appendix A.(3) Point same on all drivers.(4) No tolerance for gaging diameter is given. If the gaging diameter of the gage used differs from tabulated value, the pro-



14


Table 3A Dimensions of Slotted Close Tolerance 100 deg Flat Countersunk HeadMachine Screws

Nominal SizeHead Slot Slotor Basic Head Gaging

Diameter, Width, Depth, Protrusion Above GagingScrew Height, Diameter,A J T Diameter, F [Note (3)]Diameter H, Ref. G

[Note (1)] Max. Min. [Note (2)] Max. Min. Max. Min. Max. Min. [Note (3)]

4 0.1120 0.212 0.188 0.049 0.039 0.031 0.024 0.017 0.025 0.019 0.1676 0.1380 0.262 0.235 0.060 0.048 0.039 0.030 0.022 0.028 0.021 0.2148 0.1640 0.312 0.282 0.072 0.054 0.045 0.036 0.027 0.031 0.023 0.261

10 0.1900 0.362 0.329 0.083 0.060 0.050 0.042 0.031 0.034 0.026 0.307

1⁄4 0.2500 0.477 0.437 0.110 0.075 0.064 0.055 0.042 0.040 0.031 0.4155⁄16 0.3125 0.597 0.550 0.138 0.084 0.072 0.069 0.053 0.047 0.037 0.526

3⁄8 0.3750 0.717 0.662 0.165 0.094 0.081 0.083 0.065 0.053 0.042 0.6387⁄16 0.4375 0.837 0.774 0.193 0.094 0.081 0.097 0.076 0.060 0.047 0.750

1⁄2 0.5000 0.957 0.887 0.221 0.106 0.091 0.111 0.088 0.066 0.053 0.8629⁄16 0.5625 1.077 1.000 0.249 0.118 0.102 0.125 0.099 0.073 0.058 0.974

5⁄8 0.6250 1.197 1.112 0.276 0.133 0.116 0.139 0.111 0.080 0.063 1.086





15


Table 3B Dimensions of Type I Cross Recessed Close Tolerance 100 deg Flat CountersunkHead Machine Screws

ProtrusionNominalHead Recess Above GagingSize or Head Gaging

Diameter, Penetration Diameter, FBasic Screw Height, Recess Recess Recess Diameter,A Gaging Depth [Note (3)]Diameter H, Ref. Diameter, Depth, Width, Driver G


4 0.1120 0.212 0.188 0.049 0.110 0.070 0.018 1 0.071 0.055 0.025 0.019 0.1676 0.1380 0.262 0.235 0.060 0.148 0.074 0.027 2 0.075 0.052 0.028 0.021 0.2148 0.1640 0.312 0.282 0.072 0.162 0.090 0.028 2 0.090 0.067 0.031 0.023 0.261

10 0.1900 0.362 0.329 0.083 0.178 0.104 0.030 2 0.105 0.082 0.034 0.026 0.307

1⁄4 0.2500 0.477 0.437 0.110 0.240 0.124 0.033 3 0.118 0.095 0.040 0.031 0.4155⁄16 0.3125 0.597 0.550 0.138 0.310 0.157 0.053 4 0.148 0.126 0.047 0.037 0.526

3⁄8 0.3750 0.717 0.662 0.165 0.336 0.182 0.056 4 0.173 0.151 0.053 0.042 0.6387⁄16 0.4375 0.837 0.774 0.193 0.360 0.207 0.060 4 0.198 0.176 0.060 0.047 0.750

1⁄2 0.5000 0.957 0.887 0.221 0.386 0.234 0.063 4 0.226 0.204 0.066 0.053 0.8629⁄16 0.5625 1.077 1.000 0.249 0.418 0.265 0.069 4 0.256 0.234 0.073 0.058 0.974

5⁄8 0.6250 1.197 1.112 0.276 0.504 0.265 0.073 5 0.248 0.222 0.080 0.063 1.086





16


Table 3C Dimensions of Type IA Cross Recessed Close Tolerance 100 deg Flat CountersunkHead Machine Screws

ProtrusionNominalHead Recess Above GagingSize or Head Gaging

Diameter, Penetration Diameter, FBasic Screw Height, Recess Recess Recess Diameter,A Gaging Depth [Note (3)]Diameter H, Ref. Diameter, Depth, Width, Driver G


4 0.1120 0.212 0.188 0.049 0.110 0.070 0.029 1 0.068 0.052 0.025 0.019 0.1676 0.1380 0.262 0.235 0.060 0.148 0.077 0.041 2 0.071 0.053 0.028 0.021 0.2148 0.1640 0.312 0.282 0.072 0.162 0.092 0.041 2 0.086 0.068 0.031 0.023 0.261

10 0.1900 0.362 0.329 0.083 0.178 0.107 0.041 2 0.101 0.083 0.034 0.026 0.307

1⁄4 0.2500 0.477 0.437 0.110 0.240 0.126 0.056 3 0.114 0.096 0.040 0.031 0.4155⁄16 0.3125 0.597 0.550 0.138 0.310 0.163 0.085 4 0.145 0.127 0.047 0.037 0.526

3⁄8 0.3750 0.717 0.662 0.165 0.336 0.187 0.085 4 0.170 0.152 0.053 0.042 0.6387⁄16 0.4375 0.837 0.774 0.193 0.360 0.208 0.086 4 0.194 0.176 0.060 0.047 0.750

1⁄2 0.5000 0.957 0.887 0.221 0.386 0.239 0.086 4 0.222 0.204 0.066 0.053 0.8629⁄16 0.5625 1.077 1.000 0.249 0.418 0.271 0.086 4 0.253 0.235 0.073 0.058 0.974

5⁄8 0.6250 1.197 1.112 0.276 0.488 0.256 0.097 5 0.228 0.207 0.080 0.063 1.086





17


Table 3D Dimensions of Type II Cross Recessed C

Documents

Machine Screws and Machine Screw Nuts€¦ · ASME B18.6.3-2003 (Revision of ASME B18.6.3-1998) ASME B18.6.3–2003 (Revision of ASME B18.6.3–1998) Machine Screws and Machine Screw