1、DETAIL SPECIFICATIONFASTENER ELEMENT, SELF-LOCKING, THREADED FASTENER, 250F MAXIMUMThis specification is approved for use by all Departments and Agencies of the Department ofDefense.1. SCOPE1.1 Scope. This specification defines the requirements for self-locking elements for use inexternally threaded
2、 fasteners such as bolts and screws to be used in fasteners with either UNC,UNJC, UNF, UNJF, UNRC or UNRF threads and where the temperatures will not exceed 250F.1.2 Classification. This specification includes three types of self-locking elements as follows:Type N . . . . . Plug/PelletType L . . . .
3、 . StripType P . . . . . PatchBeneficial comments (recommendations, additions, deletions) and any pertinent data whichmay be of use in improving this document should be addressed to: Commander, Naval AirWarfare Center Aircraft Division, Code 414100B120-3, Highway 547, Lakehurst, NJ08733-5100, by usi
4、ng the Standardization Document Improvement Proposal (DD Form1426) appearing at the end of this document or by letter.AMSC N/A FSC 53GP.DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.INCH-POUNDMIL-DTL-18240F2 JUNE 1997SUPERSEDINGMIL-F-18240E1 DECEMBER 1989Provided b
5、y IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-18240F22. APPLICABLE DOCUMENTS2.1 General. The documents listed in this section are specified in sections 3 and 4 of thisspecification. This section does not include documents cited in other sections of t
6、his specification orrecommended for additional information or as examples. While every effort has been made to ensurethe completeness of this list, document users are cautioned that they must meet all specifiedrequirements documents cited in sections 3 and 4 of this specification, whether or not the
7、y are listed.2.2 Government document.2.2.1 Specifications Standards and handbooks. The following specifications, standards, andhandbooks form a part of this document to the extent specified herein. Unless otherwisespecified, the issues of these documents are those listed in the issue of the Departme
8、nt of DefenseIndex of Specification and Standards (DODISS) and supplement thereto, cited in the solicitation(see 6.2).SPECIFICATIONSFEDERALQQ-P-416 - Plating, Cadmium (Electrodeposited).GGG-W-686 - Wrench, Torque, Unidirectional.DEPARTMENT OF DEFENSEMIL-S-7742 - Screw Threads, Standard, Optimum Sele
9、cted Series: GeneralSpecification forMIL-S-8879 - Screw Threads, Controlled Radius Root with Increased MinorDiameter, General Specification for.STANDARDSFEDERALFED-STD-H28/2 - Screw Threads Standards for Federal Services Section 2Unified inch Screw Threads UN and UNR Thread FormsDEPARTMENT OF DEFENS
10、EMIL-STD-1312-7 - Fastener, Test Methods, Method 7, VibrationMS15981 - Fasteners, Externally Threaded, Self-locking, Design andUsage Limitations ForProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-18240F3AIR FORCE - NAVY AERONAUTICALAN 3 THRU
11、AN 20 - Bolt, Machine, Aircraft.(Unless otherwise indicated, copies of the above specifications, standards, and handbooks areavailable from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D,Philadelphia, PA 19111-5094.)2.2.2 Non-Government publications. The following documents
12、 form a part of this documentto the extent specified herein. Unless otherwise specified, the issues of the documents which areDoD adopted shall be those listed in the issue of the DoDISS cited in the solicitation. Unlessotherwise specified, the issues of documents not listed in the DODISS are the is
13、sue of thedocuments cited in the solicitation (see 6.2).AMERICAN SOCIETY FOR QUALITY CONTROL (ASQC)ASQC Z1.4- Sampling Procedures and Tables for Inspection by Attributes(Application for copies should be addressed to AMERICAN SOCIETY FOR QUALITY CONTROL, P.O. Box 3005, 611 E Wisconsin Ave, Milwaukee,
14、 WI 53201-4606)AMERICAN SOCIETY OF MECHANICAL ENGINEERSASME B1.1- Unified Inch Screw Threads (UN and UNR Thread Form) (DoD adopted)(Application for copies should be addressed to American Society of Mechanical Engineers (ASME), 22 Law Drive, P.O. Box 2900, Fairfield NJ 07007-2900)NATIONAL AEROSPACE S
15、TANDARDS (NAS)NAS 600 THRU NAS 606- Screw, Machine, Aircraft, Pan Head, Cruciform Recess,Full Threaded, Alloy Steel. (DoD adopted)(Application for copies should be addressed to the Aerospace Industries Association of America, Inc., 1250 Eye Street, N.W., Washington, DC 20005.)AMERICAN SOCIETY FOR TE
16、STING AND MATERIALSASTM D1535 - Standard Practice for Specifying Color By The MunsellSystem(Application for copies should be addressed to the American Society for Testing and Materials, 100 Barr Harbor Drive, W. Conshohocken, PA (19428-2959).Provided by IHSNot for ResaleNo reproduction or networking
17、 permitted without license from IHS-,-,-MIL-DTL-18240F42.3 Order of precedence. In the event of a conflict between the text of this document andthe references cited herein (except for related associated specifications or specification sheets), thetext of this document shall take precedence. Nothing
18、in this document, however, supersedesapplicable laws and regulations unless a specific exemption has been obtained.3. REQUIREMENTS3.1 Qualification. The self-locking elements furnished under this specification shall beproducts which are authorized by the qualifying activity for listing on the applic
19、able qualifiedproducts list (QPL) before contract award (see 4.2 and 6.3).3.1.1 Extent of qualification. Qualification approval of external self-locking element in UNFor UNJC external thread constitutes approval of external self-locking element in UNC, UNJC,UNF, UNJF, UNRC, or UNRF external thread o
20、f the same diameter.3.2 Design. The self-locking element design shall conform to the types illustrated onfigure 1 and MS15981.3.2.1 Dimensions. The self-locking element dimensions shall be as specified in table I,table IA, and figure 1. In cases of dimensional conflict, the dimensions of table I, ta
21、ble IA andfigure 1 shall take precedence over those identified in MS15981.3.3 Performance characteristics.3.3.1 Torque. The self-locking fastener shall conform to the torque test as specified in 4.4.2.3.3.2 High temperature torque. The self-locking fastener shall conform to the hightemperature torqu
22、e test in 4.4.3.3.3.3 Off prevailing torque at maximum temperature. The self-locking fastener shall meetthe off minimum prevailing torque values specified in table II at maximum temperature whentested in accordance with 4.4.4.3.3.4 Vibration. The self-locking fastener shall be subjected to and pass
23、the vibration testfor 30,000 cycles as specified in 4.4.5. For qualification purposes, the activity responsible forqualification may waive the vibration requirement for thread sizes greater than .500 inch providedthe .500 inch thread size having the same type locking element has passed the vibration
24、 test. Thevibration test is not required for thread sizes below .190.3.4 Reusability. The self- locking fastener shall be capable of 5 seated cycles withoutdamage to either the nut or bolt threads (see 4.4.2d through f and 4.4.6).3.5 Identification.Provided by IHSNot for ResaleNo reproduction or net
25、working permitted without license from IHS-,-,-MIL-DTL-18240F53.5.1 Self-locking element. The self-locking element shall be identified by color code asidentified in ASTM D1535 and in table VIII.3.5.2 Color. Each manufacturer of the products specified herein shall color code theirself-locking element
26、s produced per this specification in accordance with their designated colorsidentified per QPL-18240.3.6 Workmanship. Workmanship shall be consistent with high-grade commercial practice.Parts are required to be free of burrs and slivers except slight burrs are permissible in the area ofthe self-lock
27、ing element provided maximum locking torque values specified in table II are notexceeded.4. VERIFICATION4.1 Classification of inspections. The inspection requirements specified herein are classifiedas follows:a. Qualification inspection (see 4.2).b. Quality conformance inspection (see 4.3).4.1.1 Res
28、ponsibility of the self-locking element supplier. The self-locking element suppliershall be responsible for compliance with all the requirements of sections 3 and 4. The seller of thecompleted fastener shall be responsible for proving that the fastener product has met all thequality conformance insp
29、ections of the completed fastener.4.2 Qualification inspection. Qualification inspection shall be performed at a laboratoryacceptable to the Government on sample units produced with equipment and procedures normallyused in production. Qualification inspections shall be as specified in table VII. Qua
30、lificationinspection shall be limited to the fasteners shown in tables IV and shall be authorized only uponpresentation of certified test reports to the activity responsible for qualification. The test reportsshall include actual results of all the tests and a drawing which shows the location, size,
31、 material,method of attachment and protrusion of the self-locking element for each diameter upon whichqualification is desired. A manufacturers designation shall be submitted for the locking elementto be used in each diameter of fastener. For qualification of sizes up to and including .500“(governme
32、nt designation 80), the manufacturer must submit samples for full testing to beconducted by the qualifying test facility for each individual desired size. For qualification of sizesabove .500“ nominal diameter size, the manufacturer must submit actual torque test data andsamples of the specific size
33、 to the qualifying testing facility and must be qualified to the .500“nominal diameter size.4.2.1 Retention of qualification. Certification shall be requested by Naval Air WarfareCenter from each manufacturer and forwarded to the preparing activity for those specificationswhich do not contain a requ
34、irement for retention of qualification by testing. Certification shall beat the time of the two year review and shall be signed by a responsible official or management,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-18240F6attesting that the
35、listed product(s) is still available from the listed plant, and is produced under thesame conditions as originally qualified; i.e., same process, materials, construction, design,manufacturers part number, or designation, and meets the requirements of the current issue of thespecification. Failure to
36、 provide the certification will be cause for removal from the QPL.4.2.2 Sampling instructions. The qualification inspection samples shall consist of 60fasteners with the self-locking elements conforming to table IV for each diameter for whichqualification is desired. All test nuts necessary for the
37、inspections shall conform to tables VA andVB and shall be furnished by the manufacturer. Samples shall be identified as required andforwarded to the activity designated in the letter of authorization from the activity responsible forqualification (see 6.3).4.3 Quality conformance inspection. Prior t
38、o installation of the self-locking element, thequality conformance inspections of the applicable fastener specification shall be met. In addition,after installation of the self-locking element on to the applicable fastener, the quality conformanceinspections specified in table VI shall be met. Also,
39、 the self-locking fastener shall meet any othertests which are considered necessary by the procuring activity to determine conformance with therequirements of this specification. Any rework of the fastener as defined by the Fastener QualityAct shall require retesting.4.3.1 Sampling. For the quality
40、conformance inspections specified herein, the sample self-locking fasteners shall be selected at random from each finished lot as specified in 4.3.1.1. GroupA quality conformance inspection sampling shall be in accordance with ANSI/ASQZ 1.4-1993,single sampling inspection, Level II, of zero acceptan
41、ce level. Group B torque inspection samplingshall be in accordance with the sampling plan in table IX orX at the suppliers option.4.3.1.1 Lot. A lot shall consist of finished fasteners with the self-locking elementincorporated which are of the same diameter and length, fabricated by the same process
42、, heattreated in the same manner, and produced as one continuous run or order or part thereof,whichever is of the smaller quantity.4.4 Methods of inspection.4.4.1 Examination of product. The self-locking fastener shall be examined for the followingitems before any other tests are conducteda. Presenc
43、e of self-locking element.b. Location of self-locking element.c. Dimensions of self-locking element.d. Presence of burrs and slivers (see 3.6).Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-18240F7e. Identification of product.4.4.2 Torque te
44、st. For qualification testing 10 sample fasteners with self-locking elementsinstalled as specified in table IV shall be tested with the test nuts specified in tables VA and VB.For quality conformance purposes, the bolts shall be as specified in the applicable document whichrequires a self-locking el
45、ement per MIL-DTL-18240 and the test nut shall be as specified in tableVA and VB for the correct thread type. The following test shall be performed:NOTE: Parts that can not be seated shall be tested unseated.a. Prior to the actual testing of self-locking screws and bolts, a test nut asspecified in t
46、able VA and table VB with the same thread form, class and pitch,shall be gauged with a go and no go threaded plug gage. The test nut shall notaccept the no go gage for more than 1.5 turns and shall freely accept the go gagefor the entire length of the nut. The minor thread diameter shall also be che
47、ckedfor conformance with table VA and VB.b. A light lubricating oil shall be applied directly to the locking element prior totorque testing, unless otherwise specified. ( see 6.4.1)c. The torque shall be measured using a calibrated torque wrench in accordancewith GGG-W-686 or a digital torque sensor
48、 capable of measuring the torquevalues encountered during the test. (see 6.4.2)d. A self-locking fastener shall be assembled with hardened spacers, or washers asnecessary, and a test nut. The total thickness of the spacers and washers for thetest assembly shall be selected so that the locking elemen
49、t of the self-lockingfastener is fully engaged in the test nut. Set screws shall be tested in a blind hole.If the self-locking fastener is turned, the restraining mechanism shall be such that itimparts no radial load to the nut. For testing of self-locking fastener withoutsufficient thread length for a locking element in accordance with table I or forthread sizes not covered in table II only a positive indication of off prevailingtorque is required f
