ASME B18.18.1 pdf free download
ASME B18.18.1 pdf free download Inspection and Quality Assurance for General Purpose Fasteners
1 GENERAL INFORMATION1.1 Basic Plan Structure
This Standard outlines a Quality Assurance Plan forinternally and externally threaded fasteners and acces-sories or associated parts.Provisions are included forsampling plans, inspection frequencies, control proce-dures,and record keeping.
Included in this plan are fasteners for general purposeapplications, such as those where hand assembly isemployed and cost is probably of prime consideration.This plan relies on judicious manufacturing controls andinspections by the producer and, should a dispute arise,provides an inspection plan for lot compliance aftershipment.
This Standard will be used in conjunction with otheraccepted standards for product, testing. gaging, andmaterial; therefore, those provisions, as well as packag-ing, are not included herein.
1.2 Inspection Levels
The substantial difference in importance to the userof various characteristics and the dissimilar degrees ofcontrol in manufacture make impractical the subjectingof all characteristics to the same degree of inspection.Therefore, three inspection levels have been provided.Any additional characteristics deemed applicable bythe user that do not appear in the plan shall be explicitlydesignated by the user, preferably on engineering draw-ings and related specifications by the appropriate codeletter at the time of ordering (see Nonmandatory Appen-dix B).To assist in arriving at the most appropriate
inspection level, the Decision Table included in Non-mandatory Appendix A is recommended for guidance.1.3 Lot Sizes
When the acceptance number for sampling by attri-butes is fixed, variation in sample size results in variationof acceptable quality.Therefore, to avoid this inconsist-ency, fixed sample sizes are applied for the greatest rangeof lot size. Sample sizes for lots up to 250,0o0 pieces areshown in Table 1; however, for lot sizes exceeding
250,000 pieces,Table 1,Note (2) shall apply.
1.4 Measuring and Testing Equipment
All inspection and testing equipment shall be cali-brated and traceable to the National Institute of Stan-dards and Technology (NIST) standard or an equivalent national or international Standard.All calibration proce-dures shall comply with the requirements of ISo i7025,General Requirements for the Competence of Testingand Calibration Laboratories.
1.5 Basic Plan Outline
The basic plan outline as shown in Fig. 1 is includedto enhance understanding and use.
1.6 References
The following is a list of publications referenced inthis Standard.
ASME B1.3M,Screw Thread Gaging Systems for Accept-ability — Inch and Metric Screw Threads (UN,UNR,uNJ, M, and MJ)
Publisher: The American Society of Mechanical Engi-neers (ASME),Three Park Avenue, New York,NY10016-5990; Order Department: 22 Law Drive, P.O.Box 2300,Fairfield, NJ07007-2300
ISO 17025,General Requirements for the Competenceof Testing and Calibration Laboratories
Publisher: International Organization for Standardiza-
tion (IsO), 1 rue de varembe’, Case Postale 56,CH-1211,Geneve 20,Switzerland/Suisse
2GENERAL PURPOSE FASTENERS2.1 Scope
This Standard outlines the inspection plan to beemployed when lot compliance after shipment of gen-erai purpose fasteners is questioned by the user.Theproducer is responsible for supplying a product of satis-factory quality through judicious manufacturing con-trols and inspection.
2.2 Applicable Characteristics
The general plan outlines the significant applicablecharacteristics that are described by related specifica-tions and engineering drawings.Three levels of inspec-tion —A，B, and c -are employed.Each characteristicis assigned an appropriate level.These characteristics
and corresponding inspection levels are listed in Tables1 through 3 for various types of products.
Any additional characteristics deemed applicable by the user that do not appear in the plan shall be desig- nated by the user, preferably on engineering drawing and related specifications at the time of ordering. If the reference procedure of this plan is applied and an unspecified characteristic questioned, Fig. A-1 included in Nonmandatory Appendix A should be used to estab- lish the inspection level of the characteristic in question.
