General Specification

Transcription

1 General Specification CODE IDENT NO SPEC NO. ES504255, REV I ISSUE DATE 2/9/99 SUPERSEDING ES H DATED 6 JANUARY 1999 TORQUE REQUIREMENTS MECHANICAL THREADED FASTENERS (SPACECRAFT STRUCTURE EQUIPMENT) GENERAL SPECIFICATION FOR * Printed copies of this document may not be current and should not be used for official purposes. The current version is in the DMIE Information System at Jet Propulsion Laboratory California Institute of Technology

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3 TABLE OF CONTENTS Section Page 1. SCOPE Contents Purpose Nonstandard Torques APPLICABLE DOCUMENTS Listing REQUIREMENTS Conflicting Requirements Installation Holes Hole Preparation Diameters Perpendicularity Finish Circularity Cleaning Fastener Threads Unified National Thread J Form Thread Preferred Threads Bolt Stress Area Bolts, Screws and Nuts Preferred Parts Installation Quantity of Fasteners Used Wrenches Torque Application Installation Torque Standard Torque Values Self-Locking Fasteners Thread Engagement Washer Identification Self-Locking Features Replacement Criteria Thread Length Bolt and Screw Length Grip Adjustment Washers Washers with Flush Head Fasteners Design Torque Requirements Preloads Fasteners assembly Tapped Holes Preloads for Bolts/Screws Installed Into Inserts...8 i

4 Special Preloads Special Torque Values Electronic Equipment and Assembly Nylon Screws and Nuts Torque Installation Torque Torque Coefficient K Torque Wrench Personnel Overtorqued Fasteners Retorquing Multiple Installations Lubrication Torque Tables Self-Locking Fasteners QUALITY ASSURANCE Torque Inspection Thread Length Inspection Tooling Torque Wrenches Tool Accuracy Tool Selection Calibration Sealing and Marketing Recalibration Adapters PREPARATION FOR DELIVERY NOTES Intended Use Formulas Used Definitions Maximum Locking Torque Breakaway Torque...12 ii

5 TABLE OF CONTENTS (cont'd) Table Page I. Rivnuts...13 II. Inserts, Bolts/Screws, and Nuts at 80 ksi...13 III. Blind Nuts and Anchor Nuts at 125 ksi...14 IV. Bolts/Screws, at 160 ksi, Into Inserts Assembled in 6061-T6 Aluminum...15 V. Bolts/Screws, at 190 ksi, Installed Into Inserts Assembled in 6061-T6 Aluminum Alloy VI. Bolts/Screws, at 160 ksi, Into Invar and Higher Shear Strength Aluminum Alloy...17 VII. Bolts/Screws, at 190 ksi, Into Invar and Higher Shear Strength Aluminum Alloy...18 VIII. Bolts/Screws, at 160 ksi, assembled in Tapped Material...19 IX. Bolts/Screws, at 190 ksi, assembled in Tapped Material...20 X. Maximum Prevailing and Minimum Breakaway Torque...21 XI. Nylon Fasteners Assembly Torque...21 XII. Thread Engagement and Protrusion...21 iii

6 1. SCOPE 1.1 Contents. This engineering specification defines the standard torque to be applied to threaded fasteners during spacecraft assembly. 1.2 Purpose. The amount of torque applied establishes the preload in the fastener and the joint clamp-up. Incorrect preload may result in: a. Static failure of the fastener. b. Static failure of a joint member. c. Fatigue failure of the fastener. d. Joint Separation. e. Joint Slip. 1.3 Nonstandard Torques. Nonstandard torque values not covered in this specification shall be called out on the controlling drawing, with any applicable procedures to be applied, as a drawing note. 2. APPLICABLE DOCUMENTS 2.1 Listing. The following documents, of the issue as specified in the contractual instrument (or as specified for use within JPL), form a part of this specification to the extent specified herein: SPECIFICATIONS JPL ES Torque Requirements, Threaded Fasteners, Electronic Packaging Equipment, General Specification for Federal GGG-W-686 Wrench, Torque Military MIL-S-7742 MIL-S-8879 MIL-DTL MIL-DTL Screw Threads, National and Unified National, Preferred Sizes Screw Threads, Controlled Radius Root with Increased Minor Diameter, General Specification for Fastener Element, Self-Locking, Threaded Fastener, 250? F Max. Nut, Self-Locking, 250 Deg F, 450 Deg F, and 800 Deg F NASC NAS618 Fastener-Recommended Shank, Hole and Head-to-Shank Fillet Radius for 3

7 STANDARDS JPL DS83 Screw, Internal Wrenching, 160 ksi and 190 ksi DS132 Screw, Pan Head, Hi-Torque Recess, Full Thread, 160 ksi CRES DS134 Screw, Countersunk Head, Hi-Torque Recess, Full Thread, 160 ksi and 190 ksi, CRES DS136 QAI ST10051 ST10060 ST10072 ST10073 ST10224 ST10225 ST11326 ST11294 Bolt, Close Tolerance 12-Point External Wrench, 160 ksi and 190 ksi, CRES Calibration Torque Devices Screw, Cap, Socket Head Hexagon, 80 ksi, CRES Nut, Hexagon, Self-Locking, CRES Screw, Pan Head, Cross Recess, 80 ksi, CRES Screw, Pan Head, Hi-Torque Recess, 160 ksi, CRES Rivnut, Blind, Flat Head, Closed End, Keyed, Aluminum Alloy Rivnut, Blind, Countersunk Head, Closed End, Keyed, Aluminum Alloy Insert, Non-Locking, Threaded, Miniature, Open End Rivnut, Blind, Flat Head, Open End, Keyed, Aluminum Alloy Washer, Countersunk, CRES Federal FED-STD-H28 Screw Thread Standards for Federal Services Military MS21076 MS24693 MS35649 MS35650 MS35691 Nut, Self-Locking, Plate, Two Lug Floating, UNC and UNF2A CRES Screw, Machine, Flat Countersunk Head, Gross Recess Nut, Plain, Hexagon, Machine, UNC-2B, CRES Nut, Plain, Hexagon, Machine, UNF-2B, CRES Nut, Plain, Hexagon, UNF-2B, CRES 4

8 MS51957 MS51958 Screw, Machine, Panhead, Cross Recess, UNC-2A, CRES Screw, Machine, Panhead, Cross Recess, UNF-2A, CRES NASC NAS1216 NAS1351 NAS1352 NAS1348 NAS1394 NAS1395 NAS1580C Screw, Pan Head Slotted Dovetail Recess, Full Threaded Self-Locking Optional Screw, Cap, Socket Head Undrilled and Drilled, Plain and Self-Locking Alloy Steel, Corrosion-Resistant Steel and Heat-Resistant Steel, UNRF-3A Screw, Cap, Socket Head Undrilled and Drilled, Plain and Self-Locking Alloy Steel, Corrosion-Resistant Steel and Heat-Resistant Steel, UNRC-3A and UNRC-2A Fasteners - Recommended Tensile Stress Areas for External Threaded Insert, Threaded, Metal, Lightweight, CRES Insert, Threaded, Metal, Heavy Duty, CRES Bolt, Countersunk Head, CRES Commercial Hi-Shear Corp. (CAGE 73197) BB414 BB415 Blind Nut Assembly, Blind Expander Blind Nut Assembly, Expander Rexnord, Inc. (CAGE 29372) KNB( )J KNCB( )J KNC( )J KNHB( )J Insert, Non-Locking, Lightweight, Blind Insert, Non-Locking, Miniature, Blind Insert, Non-Locking, Miniature Insert, Non-Locking, Heavy Duty, Blind Shur-Lok Corp. (CAGE 97393) SL6061C SL6096C Insert, Blind, Threaded Molded-in, CRES Insert, Threaded, Molded-in, CRES 5

9 (Copies of specifications, standards, procedures, drawings, and publications required by suppliers in connection with specific procurement functions should be obtained from the procuring activity or as directed by such activity.) 3. REQUIREMENTS 3.1 Conflicting Requirements. Conflicts arising between the requirements of this specification and the requirements of any document referenced herein shall be referred to the procurement activity, if any, or if not, to the cognizant engineer of the Mechanical Engineering Section (352) for resolution. 3.2 Installation Holes Hole Preparation Diameters. Where possible, hole diameters and tolerances shall conform to NAS Perpendicularity. Holes shall be drilled perpendicular to the surface within ±0.5 degree Finish. Holes shall be smooth and free from any drill chatter or scoring marks Circularity (Roundness). Holes shall be round within the best shop practice. Holes may be reamed for shear and critical applications Cleaning. After the holes are machined, they shall be cleaned to remove all contaminants before the bolts are installed. 3.3 Fastener Threads. There will be two different fastener thread series referenced in this document Unified National Thread. The Unified National inch thread conforms to FED-STD-H28 and MIL-S J Form Thread. The J form thread has the MIL-S-8879 thread form Preferred Threads. The J form threads are preferred. The J form external thread shall not be used with internal Unified National form, MIL-S-7742, without the specific approval of the cognizant engineer Bolt Stress Area. Bolt root areas are used to calculate the preloads listed herein. (See 6.2a) Bolts, Screws and Nuts. The bolt, screw or nut shall not be reworked in any manner; this includes drilling, filing, cutting, using a tap or die, or any other mutilation, unless approved by the cognizant engineer, reidentified and inspected by QA Preferred Parts. The listing of a part in the Torque Tables does not imply the part is approved for general use. See Section 352 Fastener Specialist for approvals. 3.4 Installation Quantity of Fasteners Used. Only as many fasteners as are anticipated to be installed and 6

10 tightened during a work shift shall be taken from protective stores. Fasteners not used shall be returned to protective storage containers at the end of the shift Wrenches. Sockets and wrenches shall not have sharp edges or burrs that could damage the fastener plating or coating Torque Application. Torque shall be applied to the nut to the maximum extent possible when a nut is present. Whenever clearance is a problem, torque may be applied to the bolt head, to the high side of the torque range specified in the torque tables Installation Torque. The torque applied at final assembly shall include the net effect of the following: a. The torque required to overcome kinetic friction between mating bearing faces and between mating threads, plus; b. The torque required to overcome the self-locking feature (if any), plus; c. The torque required to apply the desired axial load to a fastener assembly. The installation torque shall be measured only in the tightening direction Standard Torque Values. The torque values selected from Tables I through IX are based on the maximum preload capability of the weaker member of the joint (either the internally threaded or externally threaded part) Self-Locking Fasteners. The self-locking and breakaway torque of fasteners shall be measured as specified in 6.3. The self-locking torque shall be added to the value listed in the applicable table and the fastener installed to that torque value Thread Engagement. The nut, nutplate, insert, etc., shall not engage any incomplete threads adjacent to the bolt or screw shank Washer Identification. Any identification mark on the washer used under the nut shall be placed opposite the face of the nut Self-Locking Features. Threaded fasteners should contain a self-locking feature in either the external, or internally threaded part to prevent joint loosening. Self-locking bolts and screws shall be readily identifiable by marking or discrete part number Replacement Criteria. The locking elements of self-locking screws and nuts are gradually degraded with use (an average life of 5 to 10 installations). The prevailing (or running) torque of each screw shall be measured during installation, prior to type approval (TA) and flight acceptance (FA) testing and final assembly. The minimum breakaway torque requirements for certain fastener combinations are listed in Table X. When a screw or nut fails to develop the minimum breakaway torque, replace it with a new screw or nut Thread Length. Install fastener threads to extend through nuts, or nutplates to comply with the thread minimum protrusion requirements shown in Table XII. Depth of fastener threads into tapped holes or free running inserts shall be one diameter minimum. Depth of fastener threads into locking inserts shall be as above or a minimum of 1.5 threads through the locking element, whichever is greater. 7

11 8 JPL Spec ES I Bolt and Screw Length. A bolt or screw one size longer or shorter than that specified on the engineering drawing may be substituted providing: a. They are only replaced by flight certified fasteners from flight store. b. They are stock items, controlled or special order bolts and screws readily available in next length sizes Grip Adjustment. When a longer bolt or screw is substituted, additional washers may be added to the ones specified on the engineering drawing subject to the following limitations: a. The number of washers used on a fastener shall be limited to three: one washer under the head and two under the nut, or two under the head and one under the nut. b. Countersunk washers shall be installed under bolt heads with the countersunk side facing the bolt head Washers. Washers shall be used in accordance with the engineering drawing, applicable process bulletins and design standards, to reduce or eliminate threads in bearing, or to prevent dissimilar metal contact. Normally, washers shall be placed under the part of the fastener that is to be wrenched (turned) to prevent galling of the substructure. Countersunk washers (90273 or equivalent) shall be used to provide sufficient clearance for the fillet radius under the head Washers with Flush Head Fasteners. Washers shall not be used under flush heads unless specified on the engineering drawing Design Torque Requirements. Design may specify torque values not listed in the Tables herein when the design requirements dictate Preloads. Preloads shall be as specified in Tables I through IX, as applicable Fastener Assembly. Fastener assembly preload shall be based on 50 percent of the fastener tensile strength (see 6.2b) Tapped Holes. Preloads for bolts/screws assembled into tapped holes shall be limited by the parent materials shear yield strength (F sy ) (see 6.2c) Preloads for Bolts/Screws Installed Into Inserts. Preloads for bolts/screws installed into inserts that are assembled in various materials shall be based on the applicable F sy of the parent material (see 6.2d) Special Preloads. For critical preloaded structural assembly tension and shear applications, torque values based on higher percentages of tensile yield strength shall be permitted with the approval of the cognizant engineer and the Structures and Materials Review Committee. The special torque values shall be specified on the engineering drawing Special Torque Values. Preload torque may be determined by analysis as the torque value required to ensure joint assembly integrity, considering all loading, thermal, and operational environments and applicable safety factors, where torque-tension testing is not justifiable, or where data exists with similar design configuration which support the analysis Electronic Equipment and Assembly. Torque values for electric and electronic packaging

12 equipment shall be in accordance with ES Nylon Screws and Nuts. Torque values for nylon screws and nuts shall be as specified in Table XI. 3.5 Torque Installation Torque. Installation torque shall be in inch-ounces, inch-pounds, or foot-pounds (see 6.2e) Torque Coefficient K. The torque coefficient (K) shall be determined by torque-tension tests or may be estimated as follows: No lubrication on nut or bolt Lubricated threads or lubricated head/washer only and silver plated nuts onto bare A-286 bolts when torques applied to the head Silver plated nuts with unlubricated A-286 bolts, torque applied to the nut. Bolts/screws with dry film lubricated threads and head/washer, torque applied to the head, going into unlubricated inserts and tapped holes Torque Wrench Personnel. All tightening of fasteners shall be accomplished by experienced personnel using certified equipment Overtorqued Fasteners. Bolts, screws, inserts, and nuts which are tightened to torques which exceed values specified shall be removed and replaced with new fasteners Retorquing. The effect of retorquing on a fastener torque-load relationship can be significant. All activities which install fasteners should consider the potential effects on preload that retorquing fasteners can have on installed hardware Multiple Installations. On multiple bolt, screw, or nut installations (e.g., circular bolted joints, etc.) the following procedure for torquing shall apply: a. Finger tighten all fasteners. b. Snug up diagonally opposite fasteners until all fastener heads are seated. c. Torque to within proper limits in a criss-cross pattern; do not successively tighten fasteners that are next to each other Lubrication. Fasteners shall be installed in the received condition without additional lubrication Torque Tables. Torque Tables I through VII shall be used to determine the torque for the specific combinations of inserts, nuts, bolts or screws, and washers listed therein. Torque Tables VIII and IX shall be used to determine the installation torque required for installation of bolts/screws in tapped holes Self-Locking Fasteners. When self-locking fasteners are used, the torque required to overcome the locking feature's torque (running torque) shall be added to the torque value indicated in the 9

13 Table. 4.0 QUALITY ASSURANCE 4.1 Torque Inspection. All threaded fasteners torqued to the requirements of this specification shall be 100 percent inspected for proper torque during assembly. 4.2 Thread Length Inspection. Fastener thread length shall be inspected for conformance to the requirements of Tooling Torque Wrenches. Torque shall be applied to the fasteners using torque wrenches conforming to QAI and GGG-W Tool Accuracy. Wrenches shall be capable of indicating torque within ±4 percent. New tools may require two applications before the accuracy is within the ±4 percent requirements Tool Selection. The torque wrench to be used shall be chosen such that the specified torque values for a particular fastener shall be between 20 and 80 percent of the full-scale torque Calibration. Torque wrench calibration shall be checked prior to the first use and thereafter at intervals not to exceed 30 calendar days. The interval may also be adjusted by individual gage inspection card. A dated certification of such check shall be securely attached to the wrench Sealing and Marking. Torque presetting wrenches shall be sealed after adjustment and calibration check with a suitable tamperproof material. The torque to which the wrench is set shall be clearly and conspicuously marked on the wrench Recalibration. If a torque wrench is dropped, struck or otherwise damaged, or suspected of being out of calibration, the wrench shall be checked before further use and, if found to be out of calibration, the wrench shall not be used until recalibrated Adapters. Adapters or extensions shall be used with torque wrenches only when necessary. Adapters or extensions shall be used only with wrenches designed for their use and the wrench or adapter combination shall be calibrated prior to use, or correction made for actual torque by an acceptable analytical method. 5.0 PREPARATION FOR DELIVERY Not applicable. 6.0 NOTES 6.1 Intended Use. Torque values are to be used in the assembly of spacecraft structure, subassemblies, and other areas as indicated. 6.2 Formulas Used: 10

14 a. Bolt/Screw Tensile Strength (F 0 ) F 0 = A s x F tu F 0 = Tensile Strength (lbs) A s = Root Area From FED-STD-H28 (in²) F tu = Tensile Strength (psi) b. Preload (F) Fastener Assembly F = 0.5 x F tu x A s F = Fastener preload (lbs) A s = Root Area (in²) c. Preload (F) for Fastener Assembly Into Tapped Hole F = 3 x 1 n x 7 8 x F sy x d x π F = Preload (lbs) n = Fasteners Threads per inch (in -1 ) F sy = Tapped Material Shear Yield Strength (psi) d = Thread Major Diameter (in) d. Preload (F), fastener assembled into insert that has been installed in a tapped hole. F = A se x 1 L x 3 n x F sy F = Preload (lbs) L = External Thread Length of Insert (in) n = Threads per inch, External Insert Threads (in -1 ) A se = Shear Engagement Area(*) of External Insert Threads (in 2 ) F sy = Shear Yield Strength of Parent Material (psi) (*) Supplied by manufacturer of insert. e. Torque (T) Necessary to Achieve Specified Preload. T = KFd (0.95) T = Assembly Torque (in-lbs) K = Constant:Required Loading Factor, Non-dimensional F = Preload (lbs) d = Major Diameter of External Thread (in) 0.95 = Allowance for Torque Wrench Error. 6.3 Definitions. For the purpose of clarification and interpretation, the following definitions are applicable to this specification. 11

15 6.3.1 Maximum Locking Torque. The maximum torque is measured during the installation or removal cycle with no load on the base of the nut. On the first installation cycle, maximum locking torque is defined as the highest reading measured during the turn of the nut after the top of the nut is flush with the end of the bolt Breakaway Torque. After assembly, the nut shall be backed-off (counterclockwise) until the preload on the assembly is removed and then the turning shall be stopped. The breakaway torque is the torque required to start the nut turning again in a counterclockwise direction. 12

16 Table I. Rivnuts Rivnut Numbers: ST10224, ST10225 Mating Bolts/Screws: Any with 25ksi or greater tensile strength. Preferred Preload Torque Wrench Reading (Inch-Ounces) Thread Size Pounds K=0.15 K=0.21 K= Table II. Inserts, Bolts/Screws and Nuts at 80ksi Part Numbers Inserts: SL6061C, SL6096C Bolts/Screws: MS24693[1], MS51957, MS51958 ST10051, ST10072, NAS1352C, NAS1351C Nuts: MS35649, MS35650, MS35691 [2] Mating Bolt/Screw: Any with 80ksi or greater tensile strength. Preferred Preload Torque Wrench Reading(Inch-Ounces) Thread Size Pounds K=0.15 K=0.21 K= Preferred Preload Torque Wrench Reading(Inch-Pounds) Thread Size Pounds K=0.15 K=0.21 K= Notes: [1] Use 80 percent of the listed torque for MS24693 and other flush head screws. [2] MS35691 is a jam nut, use 50 percent of the listed torque. 13

17 Table III. Blind Nuts and Anchor Nuts at 125ksi. Part Numbers: Blind Nuts: BB414, BB415 Anchor Nuts: MS21076 Mating Bolts/Screws: Any with 125ksi or greater tensile Strength Preferred Preload Torque Wrench Reading(Inch-Pounds) Thread Size Pounds K=0.15 K=0.21 K=

18 Table IV. Bolts/Screws at 160ksi, into Inserts Assembled in Al 6061-T6 and Higher Strength Materials. Bolts/Screws: DS83A-()-(), DS132-()-(), DS134A-()-()[1], DS136A-()-(),NAS1580C()H[1], NAS1216E(), NAS1351N(),NAS1352N(), ST10073-(). Parent Material: Al 6061-T6 and all other materials having higher than F sy =22.5ksi Miniature Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 K=0.21 K= KNC0080J ST ST ST ST Lightweight Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 (2) K=0.21 K= KNCB0256J KNCB0440J KNCB0632J KNCB0832J KNB1032J NAS1394C KNB428J NAS1394C Heavy Duty Inserts Preferred Closed Insert Open Insert Preload Pounds Torque Wrench Reading(Inch-Pounds) Thread Size Number Number K=0.15 (2) K=0.21 K= KNHB0832J NAS1395C KNHB1032J NAS1395C KNHB428J NAS1395C Note [1]. Use 80 percent of the indicated torque values for DS134A-()-() and NAS1580C()H countersunk head parts. [2]. For fasteners and larger use the low end of the torque range. 15

19 Table V. Bolts/Screws at 190ksi, into Inserts Assembled in Al 6061-T6 and Higher Strength Materials. Bolts/Screws: DS83-()-(), DS134-()-()[1], DS136-()-() Parent Material: Al 6061-T6 and all other materials having higher than F sy =22.5ksi Miniature Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 K=0.21 K= KNC0080J ST ST ST ST Lightweight Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 (2) K=0.21 K= KNCB0256J KNCB0440J KNCB0632J KNCB0832J KNB1032J NAS1394C KNB428J NAS1394C Heavy Duty Inserts Preferred Closed Insert Open Insert Preload Pounds Torque Wrench Reading(Inch-Pounds) Thread Size Number Number K=0.15 (2) K=0.21 K= KNHB0832J NAS1395C KNHB1032J NAS1395C KNHB428J NAS1395C Note [1]. Use 80 percent of the indicated torque values for DS134-()-() countersunk head parts. [2]. For fasteners and larger use the low end of the torque range. 16

20 Table VI. Bolts/Screws at 160ksi, into Inserts Assembled in Invar and Higher Strength Aluminum Alloys. Bolts/Screws: Parent Material: DS83A-()-(), DS132-()-(), DS134A-()-()[1], DS136A-()-(),NAS1580C()H[1], NAS1216E(), NAS1351N(),NAS1352N(), ST10073-(). Invar and other materials having higher than F sy =24ksi Miniature Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 K=0.21 K= KNC0080J ST ST ST ST Lightweight Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 (2) K=0.21 K= KNCB0256J KNCB0440J KNCB0632J KNCB0832J KNB1032J NAS1394C KNB428J NAS1394C Heavy Duty Inserts Preferred Closed Insert Open Insert Preload Pounds Torque Wrench Reading(Inch-Pounds) Thread Size Number Number K=0.15 (2) K=0.21 K= KNHB0832J NAS1395C KNHB1032J NAS1395C KNHB428J NAS1395C Note [1]. Use 80 percent of the indicated torque values for DS134A-()-() and NAS1580C()H countersunk head parts. [2]. For fasteners and larger use the low end of the torque range. 17

21 Table VII. Bolts/Screws at 190ksi, into Inserts Assembled in Invar and Higher Strength Aluminum Alloys. Bolts/Screws: Parent Material: DS83-()-(), DS134-()-()[1], DS136-()-() Invar and other materials having higher than F sy =24ksi Miniature Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 K=0.21 K= KNC0080J ST ST ST ST Lightweight Inserts Preferred Closed Insert Open Insert Preload Torque Wrench Reading(Inch-Pounds) Thread Size Number Number Pounds K=0.15 (2) K=0.21 K= KNCB0256J KNCB0440J KNCB0632J KNCB0832J KNB1032J NAS1394C KNB428J NAS1394C Heavy Duty Inserts Preferred Closed Insert Open Insert Preload Pounds Torque Wrench Reading(Inch-Pounds) Thread Size Number Number K=0.15 (2) K=0.21 K= KNHB0832J NAS1395C KNHB1032J NAS1395C KNHB428J NAS1395C Note [1]. Use 80 percent of the indicated torque values for DS134-()-() countersunk head parts. [2]. For fasteners and larger use the low end of the torque range. 18

22 Table VIII. Bolts/Screws at 160ksi, Assembled into Tapped Material Bolts/Screws: DS83A-()-(), DS132-()-(), DS134A-()-()[1], DS136A-()-(), NAS1216E(), NAS1351N(), NAS1352N(), NAS1580C()H[1], ST10073-(). Part A. Tapped Al 6061-T6, F sy =22.5 ksi Torque Wrench Reading(Inch-Pounds) Tapped Thread Preload Pounds K=0.15 (2) K=0.21 K=0.25 Size Part B. Tapped Invar, F sy =24 ksi Tapped Thread Preload Pounds Torque Wrench Reading(Inch-Pounds) Size K=0.15 (2) K=0.21 K= Part A. Tapped Al 7075-T73 F sy =27.5 ksi Torque Wrench Reading(Inch-Pounds) Tapped Thread Preload Pounds K=0.15 (2) K=0.21 K=0.25 Size Part A. Tapped Titanium and Steel, F sy =50.5 ksi Torque Wrench Reading(Inch-Pounds) Tapped Thread Preload Pounds K=0.15 (2) K=0.21 K=0.25 Size Note [1]. Use 80 percent of the listed torque values for DS134A-()-() and NAS 1580C()H Flush fasteners. [2] Use the high end of the torque range when applying torque to a nut. Use the low end of the torque range when applying torque to the bolt head and using lubricated threads and a lubricated head/washer and using fasteners and larger. 19

23 Table IX. Bolts/Screws at 190ksi, Assembled into Tapped Material Bolts/Screws: DS83-()-(), DS134-()-()[1], DS136-()-() Part A. Tapped Al 6061-T6, F sy =22.5 ksi Tapped Thread Preload Pounds Torque Wrench Reading(Inch-Pounds) Size K=0.15 (2) K=0.21 K= Part B. Tapped Invar, F sy =24 ksi Tapped Thread Preload Pounds Torque Wrench Reading(Inch-Pounds) Size K=0.15 (2) K=0.21 K= Part A. Tapped Al 7075-T73 F sy =27.5 ksi Tapped Thread Preload Pounds Torque Wrench Reading(Inch-Pounds) Size K=0.15 (2) K=0.21 K= Part A. Tapped Titanium and Steel, F sy =50.5 ksi Tapped Thread Preload Pounds Torque Wrench Reading(Inch-Pounds) Size K=0.15 (2) K=0.21 K= Note [1]. Use 80 percent of the listed torque values for DS134A-()-() and NAS 1580C()H Flush fasteners [2] Use the high end of the torque range when applying torque to a nut. Use the low end of the torque range when applying torque to the bolt head and using lubricated threads and a lubricated head/washer and using fasteners and larger. 20

24 Table X. Maximum Prevailing and Minimum Breakaway Torque. Thread Size Prevailing Torque [1] Maximum (Inch-Pounds) Breakaway Torque Minimum (Inch-Pounds) Nuts [2] Bolts [3] Nuts [2] Bolts[3] [1] Prevailing torque on or off. [2] Nut torque values from MIL-DTL [3] Bolt torque values from MIL-DTL JPL Spec ES I Table XI. Nylon Fastener Assembly Torque Nylon Screw/ Nut Size Assembly Torque (Inch-Ounces) Table XII. Thread Engagement and Protrusion. Thread Size Thread Engagement with Insert Minimum Thread Protrusion Through Nut Minimum