Fasteners Nuts Bolts Specs Fits Strength Handbook
on CD

TABLE OF CONTENTS

FASTENERS . . 75-1

SECTION 1. INTRODUCTION TO THREADED FASTENERS . . 75-1
075-1.1 SCOPE . . 75-1
075-1.1.1 GENERAL.75-1
075-1.1.2 REFERENCE DOCUMENTS. 75-1
075-1.2 GENERAL . 75-2
075-1.2.1 USING FASTENERS.75-2
075-1.2.2 FASTENER MAINTENANCE PRACTICES.75-3
075-1.2.3 HI SHOCK.75-3
075-1.2.4 GLOSSARY OF TERMS. 75-4

SECTION 2. IDENTIFICATION OF FASTENERS .75-7
075-2.1 GENERAL . 75-7
075-2.2 THREAD CLASS, FIT, SERIES, AND DESIGNATION . 75-8
075-2.2.1 THREAD CLASSES. 75-8
075-2.2.1.1 Class 1. 75-8
075-2.2.1.2 Class 2. 75-8
075-2.2.1.3 Class 3. 75-8
075-2.2.1.4 Class 5. 75-8
075-2.2.2 THREAD FIT. . 75-8
075-2.2.2.1 Class 1, 2, and 3 Fit.75-8
075-2.2.2.2 Class 5 Fit.75-9
075-2.2.3 THREAD SERIES. 75-9
075-2.2.3.1 UNC (Coarse Thread) Series. 75-9
075-2.2.3.2 UNF (Fine Thread) Series. 75-9
075-2.2.3.3 UN (Constant Pitch Thread) Series. . 75-9
075-2.2.3.4 UNJ. 75-9
075-2.2.3.5 NC (National Coarse Thread) Series. 75-9
075-2.2.4 THREAD DESIGNATION. 75-9
075-2.2.5 THREAD ACCEPTABILITY, GAUGING. 75-10
075-2.2.5.1 Fastener Fit Requirements. 75-10
075-2.2.6 THREAD GAUGES. 75-10
075-2.3 IDENTIFYING REPLACEMENT FASTENERS . 75-11
075-2.3.1 DRAWING IDENTIFICATION REQUIREMENTS. 75-11
075-2.3.2 IDENTIFYING FASTENERS ON APL’S. 75-12
075-2.3.3 IDENTIFYING FASTENERS AND FASTENER STANDARD PART
075-2.4 CAPSCREWS AND INTERNAL WRENCHING BOLTS . 75-14
075-2.4.1 SOCKET-HEAD CAP SCREWS.75-14
075-2.4.1.1 Selecting Dimensional Standard .75-14
075-2.4.1.2 NAS 1351 and NAS 1352 Part Numbers. 75-18
075-2.4.1.3 Authorized Socket-Head Capscrew Substitutions. 75-19
075-2.4.1.4 Socket-Head Capscrew Substitution Requiring NAVSEA
075-2.4.1.5 Identification of Socket Head Cap Screws. 75-20
075-2.4.2 INTERNAL WRENCHING BOLTS. 75-21
075-2.4.2.1 Socket-Head Capscrews. 75-21
075-2.4.2.2 Identification Marking of Internal Wrenching Bolts. 75-21
075-2.4.2.3 Restrictions on Using Internal Wrenching Bolts. 75-21
075-2.4.3 HEXAGON-HEAD CAPSCREWS. . 75-22
075-2.4.3.1 ASME B 18.2.1 Part Numbering System. 75-22
075-2.4.3.2 Zinc and Cadmium Plated Hex Head Cap Screws. 75-23
075-2.4.3.3 Grade 8, Zinc Plated Hex Head Cap Screws. 75-26
075-2.5 WASHERS .75-26
075-2.5.1 IDENTIFYING REPLACEMENT WASHERS.75-26
075-2.5.2 COUNTERSUNK WASHERS (SINGLE SURFACE). 75-27
075-2.5.3 COUNTERSUNK WASHERS (TWO SURFACES). 75-27
075-2.5.4 LOCKWASHERS. 75-27
075-2.6 ZINC-PLATED STEEL NUTS AND WASHERS . 75-27
075-2.7 THREAD INSERTS . . 75-27
075-2.7.1 PURPOSE OF THREAD INSERT. . 75-27
075-2.8 NONSTANDARD FASTENER APPLICATIONS . 75-28
075-2.8.1 LEFT-HAND THREAD APPLICATIONS. 75-28
075-2.8.2 UNIFORM STRENGTH FASTENERS. 75-30
075-2.8.2.1 Bolt-Studs.75-30
075-2.8.3 HOLES FOR UNIFORM STRENGTH FASTENERS. 75-31

SECTION 3. THREADED FASTENER MATERIALS AND MARKING . 75-35
075-3.1 GENERAL . 75-35
075-3.2 MATERIAL REQUIREMENTS AND SPECIFICATIONS . 75-35
075-3.2.1 FASTENER REQUIREMENTS FOR MIC LEVEL I APPLICATIONS. 75-35
075-3.2.2 LEVEL I REQUIREMENTS FOR FASTENERS. 75-35
075-3.2.2.1 Procurement Specifications. 75-35
075-3.2.2.2 Fastener Identification and Control. . 75-35
075-3.2.2.3 Color Coding. 75-36
075-3.2.3 FASTENER MATERIAL CHARACTERISTICS, IDENTIFICATION
MARKINGS AND SUGGESTED USE. 75-36
075-3.2.3.1 Chemical and Physical Properties.75-36
075-3.2.3.2 Material Identification Markings.75-36
075-3.2.3.3 Material Identification Markings for Stainless Steel Fasteners. 75-37
075-3.2.3.4 Identifying Material When Fasteners Are Not Marked. 75-37
075-3.2.3.5 Manufacturer’s Markings. 75-37
075-3.3 MIL-S-1222 FASTENERS. 75-37
075-3.3.1 BACKGROUND. 75-37
075-3.3.2 MIL-S-1222 FASTENER MATERIAL MARKING. 75-38
075-3.3.2.1 300 Series Stainless. 75-38
075-3.3.2.2 400 Series Stainless Steel. 75-38
075-3.3.2.3 Marking Locations. 75-38
075-3.3.3 AVAILABILITY . 75-39
075-3.3.3.1 Fastener Part Numbers. . 75-39
075-3.3.3.2 Other Sources. 75-39
075-3.4 ISSUES AFFECTING MATERiAL SELECTION . 75-58
075-3.4.1 CORROSION. . 75-58
075-3.4.1.1 Oxidation.75-58
075-3.4.1.2 Galvanic Corrosion. 75-58
075-3.4.1.3 Design Considerations to Reduce or Eliminate Corrosion. . 75-59
075-3.4.2 HYDROGEN EMBRITTLEMENT AND STRESS CORROSION CRACKING. 75-60
075-3.4.2.1 High-Strength Steel Fasteners. 75-60
075-3.4.3 COATINGS.75-62
075-3.4.3.1 Corrosion Protection.75-62
075-3.4.3.2 Zinc and Cadmium Coatings. 75-63
075-3.4.3.3 Black Oxide Coated Fasteners. 75-63
075-3.4.3.4 Zinc Primer Coating in Accordance with DOD-P-24648. . 75-64
075-3.4.3.5 Metallic-Ceramic Coated Fasteners. . 75-66
075-3.5 HIGH-TEMPERATURE FASTENERS . 75-66
075-3.6 SUITABLE USES FOR THREADED FASTENERS .75-67
075-3.7 TELEPHONE NUMBERS AND POINTS OF CONTACT . 75-69
075-3.7.1 NAVSEA.75-69
075-3.7.2 DISC. 75-69
075-3.7.3 NAVICP-M-P (NAVAL INVENTORY CONTROL POINT), FORMERLY
SPCC (SHIPS PARTS CONTROL CENTER). 75-69

SECTION 4. FASTENER TIGHTENING .75-71
075-4.1 GENERAL . 75-71
075-4.2 TIGHTENING SEQUENCE .75-72
075-4.3 PRELOAD . 75-72
075-4.3.1 PRELOAD THEORY. 75-72
075-4.3.2 PURPOSE OF PRELOAD. 75-72
075-4.3.2.1 Preventing Loosening.75-73
075-4.3.2.2 Improving Fastener Fatigue Life.75-73
075-4.3.3 DETERMINING PROPER PRELOAD. 75-74
075-4.3.3.1 Determining Design Operating Loads. 75-77
075-4.3.3.2 Determining Torque Requirements.75-77
075-4.4 RELAXATION . 75-77
075-4.4.1 General. 75-77
075-4.4.2 INITIAL RELAXATION. 75-77
075-4.4.3 TORSIONAL RELAXATION. 75-78
075-4.4.4 LONG TERM RELAXATION. 75-78
075-4.4.4.1 Stress Relaxation. 75-78
075-4.4.4.2 Vibration Relaxation.75-78
075-4.5 Methods of establishing preload . 75-78
075-4.5.1 TORQUE CONTROL.75-79
075-4.5.1.1 Units of Measurement. . 75-79
075-4.5.1.2 Determining Required Torque. 75-79
075-4.5.1.3 Applying Torque to a Fastener. 75-81
075-4.5.1.4 Torque Wrenches. 75-81
075-4.5.1.5 Tightening Fasteners Using Torque Control. 75-81
075-4.5.1.6 Special Requirements for Spiral-Wound Gaskets. 75-82
075-4.5.1.7 Changes in Torque as Fastener Yields. 75-82
075-4.5.2 TURN-OF-NUT CONTROL. 75-82
075-4.5.2.1 The Basis of Turn Requirements.75-82
075-4.5.2.2 Units of Measurement. . 75-83
075-4.5.2.3 Initial Snugging. 75-83
075-4.5.2.4 Where to Make the Measurements. . 75-84
075-4.5.2.5 Turning the Nut. 75-84
075-4.5.3 STRETCH CONTROL.75-84
075-4.5.3.1 Determining Stretch Requirements. . 75-84
075-4.5.3.2 Measuring the Stretch.75-84
075-4.5.4 ULTRASONIC STRETCH OR STRESS CONTROL. 75-85
075-4.5.5 HYDRAULIC TENSIONING AND HEATING. . 75-85
075-4.6 THREAD LUBRICANTS . 75-85
075-4.6.1 GENERAL.75-85
075-4.6.2 THREAD LUBRICANT APPLICATION. 75-85

SECTION 5. THREADED FASTENER LOCKING .75-91
075-5.1 GENERAL . 75-91
075-5.1.1 THREADED FASTENER LOOSENING. 75-91
075-5.1.2 VIBRATION. . 75-91
075-5.1.3 LOAD CYCLING. 75-91
075-5.2 PRELOAD METHOD . 75-91
075-5.3 PREVAILING TORQUE (SELF-LOCKING NUT) METHOD . 75-92
075-5.3.1 GENERAL.75-92
075-5.3.2 REUSABLE SELF-LOCKING FASTENERS.75-92
075-5.3.2.1 Plastic Ring and Insert Fasteners.75-92
075-5.3.2.2 Reusable Metal (Spring Beam) Self-Locking Nuts. 75-94
075-5.3.3 NONREUSABLE SELF-LOCKING FASTENERS. 75-95
075-5.3.3.1 Distorted Collar Nuts.75-95
075-5.3.3.2 Distorted Thread Nuts. . 75-96
075-5.3.4 JAM NUTS (LOCK NUTS). 75-96
075-5.3.4.1 Jam Nut Assembly. 75-96
075-5.3.4.2 Tightening the Jam Nut. . 75-96
075-5.3.5 SETSCREWS. . 75-96
075-5.4 MECHANICAL METHOD . 75-97
075-5.4.1 GENERAL.75-97
075-5.4.2 PINS. 75-98
075-5.4.2.1 Cotter Pins.75-98
075-5.4.2.2 Driven Pins. . 75-99
075-5.4.2.3 Use of Hardened Drive Pins. 75-99
075-5.4.2.4 Installing Straight Pins. . 75-100
075-5.4.2.5 Installing Taper Pins.75-100
075-5.4.2.6 Aligning Holes for Pins. 75-100
075-5.4.2.7 Substitutions for Pin-Type Locking Devices.75-100
075-5.4.3 TAB LOCKS. . 75-100
075-5.4.3.1 Installing Tab Locks.75-101
075-5.4.3.2 Tab Bend Radius. 75-101
075-5.4.4 STAKING AND PEENING. 75-101
075-5.4.4.1 Staking. 75-101
075-5.4.4.2 Peening. 75-101
075-5.5 SAFETY WIRE METHOD . 75-101
075-5.5.1 GENERAL.75-101
075-5.5.2 REWIRING.75-102
075-5.5.3 TIGHTENING SAFETY WIRED FASTENERS. . 75-102
075-5.5.4 WIRE INSTALLATION. . 75-102
075-5.6 LOCKWASHER METHOD . 75-102
075-5.6.1 GENERAL.75-102
075-5.6.2 HELICAL SPRING LOCKWASHERS. 75-102
075-5.6.3 CURVED OR CONICAL SPRING LOCKWASHERS. 75-102
075-5.6.4 TOOTHED LOCKWASHERS. 75-103
075-5.6.4.1 Internal Tooth Lockwashers. 75-103
075-5.6.4.2 External Tooth Lockwashers. 75-103
075-5.6.4.3 Internal-External Tooth Lockwashers. 75-105
075-5.6.5 PART NUMBERS. 75-105
075-5.7 CHEMICAL METHOD . 75-105
075-5.7.1 GENERAL.75-105
075-5.7.2 ANAEROBIC THREADLOCKING COMPOUND. 75-106
075-5.7.2.1 Material Compatibility. . 75-106
075-5.7.2.2 Cleaning and Surface Activation Requirements. . 75-106
075-5.7.2.3 Anaerobic Compound Cure Time.75-107
075-5.7.2.4 Fastener Material Curing Characteristics. 75-107
075-5.7.2.5 Primers (Activators).75-107
075-5.7.2.6 Assembly Time Requirements. 75-107
075-5.7.2.7 Using Heat to Cure. 75-107
075-5.7.2.8 Tightening Chemically Locked Fasteners. 75-107
075-5.7.2.9 Tightening of Studs Set with Chemicals. 75-109
075-5.7.2.10 Threadlocking Compound Selection. . 75-109

SECTION 6. THREADED FASTENER REMOVAL .75-112
075-6.1 GENERAL . 75-112
075-6.1.1 CONTROL.75-112
075-6.1.2 LEFT-HAND THREADS. 75-112
075-6.1.3 AVOIDING PROBLEMS. 75-113
075-6.1.3.1 Plan Your Job. 75-113
075-6.1.3.2 Think Safety. . 75-113
075-6.1.3.3 Stubborn or Damaged Fasteners.75-113
075-6.1.4 NORMAL REMOVAL.75-113
075-6.1.5 REMOVAL OF CHEMICALLY LOCKED FASTENERS. . 75-114
075-6.1.5.1 Using Torque to Loosen. 75-114
075-6.1.5.2 Using Heat and Torque to Loosen.75-114
075-6.1.5.3 Using Chemicals and Torque to Loosen. 75-114
075-6.1.5.4 Nonanaerobic Locking Compounds. . 75-114

SECTION 7. INSTALLATION OF THREADED FASTENERS .75-114
075-7.1 GENERAL . 75-114
075-7.2 FASTENER SELECTION PROCEDURE . . 75-115
075-7.3 FIVE BASIC SITUATIONS . 75-115
075-7.3.1 GENERAL.75-115
075-7.3.2 NEW EQUIPMENT. 75-115
075-7.3.3 DAMAGED FASTENERS. 75-116
075-7.3.4 UNREPAIRABLE FASTENERS.75-116
075-7.3.5 UNIDENTIFIABLE FASTENERS. . 75-116
075-7.3.6 USE OF TEMPORARY FASTENERS. 75-116
075-7.4 SELECTION OF PROPER THREADED FASTENER SYSTEMS . 75-116
075-7.4.1 THREADED FASTENER SYSTEM. 75-116
075-7.4.2 TECHNICAL MANUALS AND SYSTEM DRAWINGS.75-117
075-7.4.3 UNAVAILABILITY OF TECHNICAL MANUALS. 75-117
075-7.5 LENGTH OF THREAD PROTRUSION .75-117
075-7.5.1 MINIMUM THREAD PROTRUSION. 75-117
075-7.5.2 MAXIMUM THREAD PROTRUSION. 75-117
075-7.6 DEPTH OF ENGAGEMENT FOR STUDS AND CAPSCREWS . . 75-118
075-7.6.1 DETERMINING REQUIRED DEPTH OF ENGAGEMENT. 75-118
075-7.7 SQUARENESS OF SPOTFACE WITH HOLE . 75-118
075-7.7.1 FASTENER-BENDING LOADS.75-118
075-7.7.2 EFFECT OF BEARING SURFACE ON TORQUE LOAD. . 75-119
075-7.8 HEX-HEAD BOLTS AND CAPSCREWS . . 75-119
075-7.8.1 DIFFERENCES BETWEEN HEX-HEAD BOLTS AND CAPSCREWS. 75-119
075-7.8.2 TYPES OF BOLTS. 75-119
075-7.8.3 THROUGH BOLTS. 75-119

075-7.8.4 CAPSCREWS IN THREADED HOLES. 75-120
075-7.8.4.1 Selecting Proper Screw Length.75-120
075-7.8.4.2 Preventing Damage to Tapped Threads. 75-120
075-7.8.4.3 Cleaning the Tapped Hole. 75-120
075-7.8.4.4 Use of Thread Locking, Lubricating, and Antiseize Compounds. 75-122
075-7.9 FITTED BOLTS .75-122
075-7.9.1 WHY AND WHERE THEY ARE USED. 75-122
075-7.9.2 HOLE PREPARATION. . 75-122
075-7.9.3 FITTED BOLT PREPARATION.75-122
075-7.9.4 ALTERNATE FITUP PROCEDURE. 75-122
075-7.10 BOLT-STUDS . 75-122
075-7.10.1 WHY AND WHERE THEY ARE USED. 75-122
075-7.10.2 TYPES OF BOLT-STUDS. 75-122
075-7.10.3 TIGHTENING. 75-124
075-7.11 STUDS . . 75-124
075-7.11.1 WHY AND WHERE THEY ARE USED. 75-124
075-7.11.2 TYPES OF STUDS. 75-124
075-7.11.3 SETTING STUDS. 75-124
075-7.11.3.1 Class 5 Fit.75-124
075-7.11.3.2 Nonstandard Class 5 Fit Threads.75-125
075-7.12 USE OF FLAT WASHERS . 75-125
075-7.12.1 GENERAL.75-125
075-7.12.2 WASHERS FOR EQUIPMENT SLIDING FOOT FASTENERS. 75-125
075-7.13 INTERCHANGEABILITY OF NUTS . 75-125
075-7.13.1 GENERAL.75-125
075-7.13.2 STANDARDS FOR PLAIN HEXAGON NUTS WITH THE SAME PART
NUMBER FOR DOUBLE CHAMFERED AND WASHER FACED
CONFIGURATIONS. . 75-125

SECTION 8. THREADED FASTENER INSPECTION AND REPAIR . 75-126
075-8.1 GENERAL . 75-126
075-8.2 INSPECTION OF INSTALLED THREADED FASTENERS AND JOINTS . . 75-126
075-8.2.1 GENERAL INSPECTION. 75-126
075-8.2.2 RUST AND CORROSION. 75-127
075-8.2.3 THREAD PROTRUSION. 75-127
075-8.2.4 TAB WASHERS. 75-127
075-8.2.5 CHECKING PRELOAD. . 75-127
075-8.3 VISUAL EXAMINATION OF FASTENERS PRIOR TO INSTALLATION . . 75-128
075-8.3.1 INSPECTING FOR PROPER APPLICATION TYPE. 75-128
075-8.3.2 HEAD DAMAGE. 75-128
075-8.3.3 RUST OR CORROSION DAMAGE. 75-128
075-8.3.4 OVERTIGHTENED (YIELDED) FASTENERS. . 75-128
075-8.3.5 THREAD FLATTENING. 75-128
075-8.3.6 SELF-LOCKING ELEMENTS. 75-128
075-8.4 ADDITIONAL EXAMINATIONS . 75-128
075-8.4.1 GALLING.75-128
075-8.4.2 CHECKING SELF-LOCKING NUTS. 75-128
075-8.5 THREAD REPAIR .75-129
075-8.5.1 GENERAL.75-129
075-8.5.2 THREAD REWORK. 75-129
075-8.5.3 THREAD FILING. 75-129
075-8.5.4 THREAD LAPPING. 75-129
075-8.6 REWORKING OF THREADED FASTENER JOINTS . . 75-129
075-8.6.1 FASTENER REMOVAL. . 75-129
075-8.6.2 SUBMARINE FASTENER APPLICATIONS.75-129
075-8.6.3 REWORK/REPLACEMENT OF CLASS 5 INTERFERENCE FIT THREADS. . 75-130
075-8.6.3.1 Replacements Using Anaerobic Compounds.75-130
075-8.6.3.2 Replacement Interference Fit Studs. . 75-130
075-8.6.4 REMOVAL AND REUSE OF ASSEMBLED STUDS. 75-131
075-8.6.5 STEPPED STUDS. 75-131

SECTION 9. REMOVING DAMAGED OR STUBBORN THREADED FASTENERS . . 75-131
075-9.1 GENERAL . 75-131
075-9.2 PREVENTING PROBLEMS .75-132
075-9.3 NORMAL REMOVAL . 75-132
075-9.4 ROUNDED-OFF NUT AND HEAD CORNERS . 75-132
075-9.4.1 GENERAL.75-132
075-9.4.2 NUTS INSTALLED ON THROUGH BOLTS AND BOLT-STUDS.75-132
075-9.4.3 NUTS ON STUDS. 75-132
075-9.4.4 CAPSCREWS. 75-133
075-9.5 SEIZED THREADS . . 75-133
075-9.6 BROKEN STUDS AND CAPSCREWS .75-134
075-9.6.1 GENERAL.75-134
075-9.6.2 NONLOCKED STUDS. . 75-134
075-9.6.2.1 Drilling an Axial Hole in a Stud.75-134
075-9.6.2.2 Using Ezy-outs. 75-134
075-9.6.2.3 Drilling Out the Stud.75-135
075-9.6.2.4 Using EDM Equipment. . 75-136
075-9.6.2.5 Power Driven Broken Bolt Extractor (NSN 5130-01-387-7451).. 75-136
075-9.6.3 CLASS 5 FIT AND LOCKED STUDS. 75-136

LIST OF TABLES