Glossary of Terms for Mechanical Fasteners

AN AMERICAN N A TIONA L S T AN D AR D

ASME B18.12-2020

(Revision of ASME B18.12-2012)

ASME B18.12-2020

(Revision of ASME B18.12-2012)

Glossary of Terms

for Mechanical Fasteners

AN AMERICAN NATIONAL STANDARD

Two Park Avenue • New York, NY • 10016 USA

Date of Issuance: June 30, 2020

This Standard will be revised when the Society approves the issuance of a new edition.

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

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CONTENTS

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

Committee Roster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Correspondence With the B18 Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

FOREWORD

Sectional Committee B18 on Dimensional Standardization of Bolts, Nuts, Rivets, Screws, and Similar Fasteners was organized in March 1922 under the procedure of the American Engineering Standards Committee (AESC), with the Society of Automotive Engineers and The American Society of Mechanical Engineers (ASME) as joint sponsors.

Subcommittee 10 on the Glossary of Terms for Mechanical Fasteners was organized in February 1947. The purpose of the subcommittee was to promote and coordinate the standardization of fastener nomenclature for those products falling under the scope of the various other subcommittees of the B18 Sectional Committee, the definitions themselves being the responsibility of the cognizant subcommittee. It was later decided that terms not strictly in the above category but closely allied should be defined in the Glossary.

During the development period, Subcommittee 10 prepared and studied several drafts of the Glossary before agreeing on a suitable format and content.

To cover completely the field of mechanical fasteners, it has been necessary to include in this Standard illustrations of certain fastener features and types of fasteners that are of proprietary origin. Because it was impossible to include all variations of such proprietary designs, this Standard includes selected illustrations that exemplify the type of fastener or feature described. This selection was made on an impartial basis. The inclusion of any one proprietary design in this Standard does not constitute endorsement by the committee or the sponsors, nor is omission of certain styles to be construed as rejection of such styles by the committee and sponsors.

ASA B18.12 was approved by the B18 Sectional Committee, the sponsors, and the AESC, which had changed its name to American Standards Association (ASA). It was designated an American Standard on June 22, 1962.

In May 1995, Subcommittee 12 of the B18 Standards Committee set forth the concept that a complete update and significant revision of the Glossary of Terms was necessary. The content was completely reorganized to reflect a logical approach to basic fastener characteristics and configurations. Many new sections and items, such as blind fasteners and retaining rings, were included. In total, 538 terms were included in the 2001 edition of ASME B18.12-2001, which was approved by American National Standards Institute (ANSI), formerly known as ASA, on August 15, 2001 and revised in 2006.

For the 2012 edition, para. 3.1.3 was revised in its entirety, and para. 3.1.4 was added. It received ANSI approval on January 9, 2012.

In May 2019, Subcommittee 12 of the B18 Standards Committee reviewed the text of this Standard and made minor revisions and changes to bring the language and definitions of the Standard up to date. This edition of ASME B18.12 received ANSI approval on January 6, 2020.

ASME B18 COMMITTEE

Standardization 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)

STANDARDS COMMITTEE OFFICERS

W. Guth, Chair

J. Medcalf, Vice Chair

A. L. Guzman Rodriguez, Secretary

STANDARDS COMMITTEE PERSONNEL

T. Anderson, Bay Bolt

L. Borowski, Greenslade & Co., Inc.

S. Brahimi, Industrial Fasteners Institute

B. Cao, Infasco

V. Cartina, Hi-Performance Fastening Systems

L. Claus, NNI Training and Consulting, Inc.

A. P. Cockman, Consultant

1. K. Cooney, The Yorkshire Group

2. S. George, Michigan Metal Coatings Co.

W. Guth, Electric Boat Corp.

A. L. Guzman Rodriguez, The American Society of Mechanical Engineers

J. Medcalf, Field Fastener

M. Q. Muhammad, Defense Logistics Agency Troop Support

J. P. Nash, Caterpillar Inc.

F. J. Perry, John Deere

C. B. Williamson, Fastenal Co.

M. Byrne, General Fasteners Co.

D. Clever, Consultant

J. F. McCarrick, Alternate, Defense Supply Center Philadelphia

R. W. Davidson, Contributing Member, Endries International, Inc.

J. J. Grey, Contributing Member, Fastener Consulting Services, Inc.

W. Guth, General Dynamics Electric Boat

J. C. Jennings, Contributing Member, Naval Surface Warfare Center, Philadelphia Division

M. Kaindl, Contributing Member, Aztech Locknut Co.

D. Korneffel, Contributing Member, CADENAS PARTsolutions

M. D. Prasad, Contributing Member, Global M&F Solutions, Inc.

J. J. Stoczanskyj, Contributing Member, Beacon Fasteners and Compo- nents, Inc.

R. D. Strong, Contributing Member, Lear Corp.

C. G. Vertullo, Contributing Member, Carver Engineering and Manu- facturing, Inc.

C. J. Wilson, Contributing Member, Consultant

B18 SUBCOMMITTEE 12 — GLOSSARY OF TERMS

J. J. Stoczanskyj, Chair, Beacon Fasteners and Components, Inc.

L. Borowski, Greenslade & Co., Inc.

S. Brahimi, Industrial Fasteners Institute

B. Cao, Infasco

D. S. George, Michigan Metal Coatings Co.

J. C. Jennings, Naval Surface Warfare Center, Philadelphia Division

R. A. Lund, Fastenal Co.

M. Q. Muhammad, Defense Logistics Agency Troop Support

J. P. Nash, Caterpillar Inc.

D. F. Sharp, TurnaSure LLC

G. M. Simpson, Semblex Corp.

Q. M. Smith III, Faurecia

C. J. Wilson, Consultant

J. F. McCarrick, Alternate, Defense Supply Center Philadelphia

D. Clever, Contributing Member, Consultant

CORRESPONDENCE WITH THE B18 COMMITTEE

General. ASME Standards are developed and maintained with the intent to represent the consensus of concerned interests. As such, users of this Standard may interact with the Committee by requesting interpretations, proposing revisions or a case, and attending Committee meetings. Correspondence should be addressed to:

Secretary, B18 Standards Committee

The American Society of Mechanical Engineers Two Park Avenue

New York, NY 10016-5990

https://go.asme.org/Inquiry

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

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

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Subject: Cite the applicable paragraph number(s) and the topic of the inquiry in one or two words. 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 approval of a proprietary design or situation. Please provide a condensed and precise question, composed in such a way that a “yes” or “no” reply is acceptable.

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Moreover, ASME does not act as a consultant for specific engineering problems or for the general application or understanding of the Standard requirements. If, based on the inquiry information submitted, it is the opinion of the Committee that the Inquirer should seek assistance, the inquiry will be returned with the recommendation that such assistance be obtained.

ASME procedures provide for reconsideration of any interpretation when or if additional information that might affect an interpretation is available. Further, persons aggrieved by an interpretation 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 Standards Committee regularly holds meetings and/or telephone confer- ences that are open to the public. Persons wishing to attend any meeting and/or telephone conference should contact the Secretary of the B18 Standards Committee. Future Committee meeting dates and locations can be found on the Committee Page at https://go.asme.org/B18committee.

ASME B18.12-2020

GLOSSARY OF TERMS FOR MECHANICAL FASTENERS

1. INTRODUCTION

   1. Scope

      This Standard is a summary of mechanical fastener terminology, related characteristics, and manufacture.

      1. Fastener. A fastener is a mechanical device designed specifically to hold, join, couple, assemble, or maintain equi- librium of single or multiple components. The resulting assembly may function dynamically or statically as a primary or secondary component of a mechanism or structure. Fasteners are used in just about every mechanical assembly, and they have been designed to meet the needs of products ranging from wristwatches to the space shuttle. Each fastener is produced with the degree of built-in precision and engineering capability needed to ensure adequate, sound service under preestablished environmental conditions.

      2. Bolts, Studs, Screws, Nuts, Washers, Rivets, Pins, and Custom-Formed Parts. These are the general product families used to classify mechanical fasteners. Within each product family are numerous fasteners whose names either conform to the technical language of a national standard or relate to their original applications, e.g.,“stove bolt” or “carriage bolt.” The names given to fasteners appear to be as limitless as the imaginations of their designers. While many fasteners may look alike, each has defined engineered capabilities based upon its intended application.

      3. Primary Operations. Mechanical fasteners are produced by forming or screw machine operations.

         1. Forming may produce thousands of fasteners per minute with looser tolerance (depending on the size and configuration of the fastener) and typically creates minimal scrap.

         2. Screw machining is significantly slower and typically produces tighter tolerance but has a higher risk of creating scrap.

      4. Secondary Operations. Fasteners typically undergo several secondary operations or processes, such as thread rolling, heat treating, or plating.

         
         

   2. Referenced Documents

      The developers of this Standard wrote a number of terms based on the language found in more than 230 standards and other publications of the following organizations:

      1. The American Society of Mechanical Engineers (ASME), Two Park Avenue, New York, NY 10016-5990 (www.asme.org)

      2. American Society for Testing and Materials (ASTM International), 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959 (www.astm.org)

      3. Industrial Fasteners Institute (IFI), 6363 Oak Tree Boulevard, Independence, OH 44131 (www.indfast.org)

      4. Research Council on Structural Connections (RCSC), c/o AISC, One East Wacker Drive, Suite 700, Chicago, IL 60601 (www.boltcouncil.org)

      5. Society of Automotive Engineers (SAE International), 400 Commonwealth Drive, Warrendale, PA 15096 (www.sae.org)

         
         

2. TERMINOLOGY

   1. Basic Fastener Terminology

1. Commercial Fastener

   commercial fastener: a fastener manufactured to published consensus standards and stocked by manufacturers and distributors.

   
   

2. Compression Fastener

compression fastener: a fastener whose primary function is to resist compressive forces.

1