7_G-F601_77751_SP_F_0001_F_NULL_0001_441_U_N_Y_N_N_Y_D.PDF

G-F601 Revision F

06 January 2016

CAGE 77751 G-F601

ii

TABLE OF REVISIONS

Revision Date Changes Reason for Change Approved

Original Issue 06/07/1971 New Document H. Kleindienst

Revision A 04/25/1974 Add Rev. to Ref. documents H. Kleindienst

Updated MS part nos. – No Impact. Old parts use to depletion.

Added X4948M and CCR264SS3 – No Impact as X4948M was put in drawing caliout prior to this issue.

Incorporated to agree with PPL alllow CCR option

Reworded. Covered diameters not previously covered.

Specified cleaning reqmts.

Changed MS20450 to MS16535, added MS16536.

Revision B 08/16/1983 Modified format To be consistent with current FRC policy.

J. Weir

Incorporated Addendum V To include all requirements unique to “crown flush” rivets.

Deleted all requirements pertaining to pull through hollow rivets.

These requirements were added to G-F603 Rev B.

Added section 3.1.4 Cadmium plated rivets shall not be used in titanium.

Added section 3.2.1.3 In order to clarify FRC policy on .0312 grip length increments.

Revised section 3.2.2 substitutions

Add obsolescence of X4948 rivets (3.2.2.5) and approved alternate sources for crown flush rivets

Added section 3.3.7.1 Highlight FRC policy on automatic riveting

Added section 5.0 FRC approved sources of supply iii

Revision Date Changes Reason for Change Approved

Revision C 07/07/1986 Incorporate alternate sources in Table III.

Revised to meet Contractor Operations Review (COR) requirements

H. Kleindienst

Revision D 01/25/1988 Added list of tables and list of figures

K. Grube

Reformatted

Remove revision letters from applicable documents and revise applicable document statement and list

Added new figure showing punch ring mark and discriptive text

Removed references to mandatory review or interfacing with Fairchild Republic (FRC) functional groups

Added tables to figures as required

Added section 6.0

Revision E 05/14/2012 Section 2.1.4 added NAS1241 and NAS1242 Repair Rivets and Updated Specification with NASM standards for applicable MS part numbers.

K.Grube

Figure 1.1 was redrawn.

Section 3.3.1.5 updated vinyl tape (3M’s #473T).

Table III added supplier information for Guardian Rivet and Fastener.

Section 3.3.6 added limit on driven heads not to exceed 1.4D times the shank diameter (D).

iv

Revision Date Changes Reason for Change Approved

Revision E continued

Table VIII Redrew and added range for driven head diameters based on new range (1.3D to 1.4D head diameter)

K. Grube

Section 3.3.9.1 added the requirements for Automatic Riveting.

Added Section 3.3.12 to include oversize rivets

Added Sections 3.3.12 and

3.4.2.1 for NAS1241 and NAS1242 Solid Repair Rivets

Renumbered Tables IX, X and

XI

Revision F 01/06/2016 Added Paragraph 3.3.5.4. Air Force request S. Miro

Added Figures 1.2 and 1.3. Air Force request

Updated Table VIII. Air Force request v

TABLE OF CONTENTS

TABLE OF REVISIONS ...................................................................................................... ii

LIST OF TABLES ............................................................................................................. vii

LIST OF FIGURES ........................................................................................................... viii

1.0 SCOPE

2.0 APPLICABLE DOCUMENTS

2.1 Government Documents

2.1.1 Federal Specifications

2.1.2 Military Specifications

2.1.3 Military Standards

2.1.4 National Aerospace Standards (NAS)

2.2 Non-Government Documents

2.2.1 A-10 Program Specifications

2.2.2 A-10 Program Standards

2.2.3 Other Documents

3.0 REQUIREMENTS

3.1 Equipment

3.2 Materials

3.2.1 Solid and Tubular Rivets

3.2.2 Codes

3.2.3 Non Standard Grip Lengths

3.2.4 Substitutions

3.3 Required Procedures and Operations

3.3.1 Fit-Up

3.3.2 Holes

3.3.3 Hole-Sizes

3.3.4 Rivet Lengths

3.3.5 Driving Procedure

3.3.6 Shop Driven Heads

3.3.7 Flush Driven Heads

3.3.8 Nut Plate Installation

3.3.9 Automatic Riveting

3.3.10 Head Flushness

3.3.11 Shaving

3.3.12 Oversize Rivets

3.4 Recommended Procedures

vi

3.4.1 Rivet Removal

4.0 QUALITY ASSURANCE

4.2 Gaps Evaluation

4.3 Acceptance Limits

4.3.1 Driven Heads

4.3.2 Cracked Driven Heads

4.3.3 Manufactured Head (as Received From Rivet Supplier)

4.3.4 Damage to Sheets

4.3.5 Shanked Rivets-Part Separation

5.0 PREPARATION FOR DELIVERY — NOT APPLICABLE

vii

LIST OF TABLES

TABLE I: NON STANDARD GRIP AVAILABILITY (1/32 INCREMENTS)

TABLE II: NUT PLATE RIVET MATERIAL

TABLE III: ACCEPTABLE ALTERNATE RIVETS

TABLE IV: SURFACE DEFECTS IN FASTENER HOLES

TABLE V: HOLE SIZES FOR SOLID RIVETS

TABLE VI: HOLE SIZES FOR TUBULAR RIVETS

TABLE VII: REQUIRED PROTRUSION BEFORE DRIVING TUBULAR RIVETS

TABLE VIII: STANDARD FLAT DRIVEN HEAD DIMENSIONS — SOLID RIVETS

TABLE IX: MINIMUM DIMENSION FOR MANUFACTURED HEADS OF

UNIVERSAL RIVETS (DRIVMATIC AND GANG RIVETING)

TABLE X: LIMITS, HEAD MARKS AUTOMATIC RIVETING

TABLE XI: DIMENSIONS — RIVETS SHAVING 100° HEADS

viii

LIST OF FIGURES

Figure 1: Quadrant Symbols

Figure 1.1: Rivet Code

Figure 1.2: Depiction of Unacceptable Reverse Drive Method

Figure 1.3: Standard Shop Practice (Head Driven Rivet) Diagram

Figure 2: Driven Head

Figure 2.1: Angular Rivet Installation

Figure 2.2: Nut Plate Installation

Figure 2.3: Punch Ring

Figure 2.4: Depressed Punch Ring

Figure 3: Exposed Countersink

Figure 4: Shim Configuration

Figure 5: Flush Head Seating Check

Figure 6: Clinched Head Solid Rivet — Not Acceptable

Figure 7: Bell Shaped Head — Not Acceptable

Figure 8: Tipped and Cut Head

Figure 9: Clinched Heads Tubular Rivets

Figure 10: Acceptable Diagonal Cracks

Figure 11: Acceptable Diagonal Cracks

Figure 12: Unacceptable Diagonal Cracks

Figure 13: Unacceptable Face Cracks

Figure 14: Acceptable Vertical Cracks

Figure 15: Unacceptable Vertical Cracks

Figure 16: Radial Cracks, Tubular Rivets

Figure 17: Head Marks, Small Die

Figure 18: Head Marks, Large Die

Figure 19: Shanking, Intermediate Materials

Figure 20: Shanking Joggled Parts

Figure 21: Shanking, Double Joggled Parts

1.0 SCOPE

This specification sets forth the requirements for the installation of 1/16 inch through 3/8 inch solid common rivets, as well as for the installation of 1/8, 5/32 and 3/16 inch nominal diameter tubular rivets.

2.0 APPLICABLE DOCUMENTS

The following documents of the issue in effect on the effective date of contract shall form part of this specification. In the event of conflict between contractual documents referenced herein and the requirements of this specification, the contractual documents referenced herein shall govern.

2.1 Government Documents

2.1.1 Federal Specifications

None

2.1.2 Military Specifications

None

2.1.3 Military Standards

Part Number

MS16535

Rivet, Tubular, Oval Head

Part Number

MS16536

Rivet, Tubular, 150º Flat Countersunk Head

Part Number

MS20426

Rivet, Solid, Countersunk 100º Precision Head, Aluminum Alloy and Titanium Columbium Alloy

Part Number

MS20427

Rivet, Solid, 100º Countersunk Head, Carbon Steel, Corrosion-Resistant Steel, Nickel-Copper and Copper

Part Number

MS20470

Rivet, Solid, Universal Head, Aluminum Alloy and Titanium Columbium Alloy

Part Number

MS20613

Rivet, Solid, Universal Head, Steel, Carbon and Steel, Corrosion- Resistant

Part Number

MS20615

Rivet, Solid, Universal Head, Brass, Copper, Nickel-Copper Alloy

2.1.4 National Aerospace Standards (NAS)

NAS1097 Rivet, Solid, 100º Flush Shear Head, Alumium Alloy

NAS1198 Rivet, Solid, Universal Head, A286 Corrosion Resistant Steel

NAS1199 Rivet, Solid, 100º Flush Head, A286 Corrosion Resistant Steel

NAS1200 Rivet, Solid, 100º Flush Shear Head, A286 Corrosion Resistant Steel and Monel

NAS1241 Rivet, Solid 100° Flush Head, Aluminum Alloy, MS20426 Repair

NAS1242 Rivet, Solid, Universal Head, Aluminum Alloy, NASM20470 Repair

NASM16535 Rivet, Tubular, Oval Head

NASM16536 Rivet, Tubular, 150º Flat Countersunk Head

NASM20426 Rivet, Solid, Countersunk 100º, Precision Head, Alumium Alloy and Titanium Columbium Alloy

NASM20427 Rivet, Solid, 100º Countersunk Head, Carbon Steel, Corrosion-Resistant Steel, Nickel-Copper and Copper

NASM20470 Rivet, Solid, Universal Head, Aluminum Alloy and Titanium Columbium Alloy

NASM20613 Rivet, Solid, Universal Head, Steel, Carbon and Steel, Corrosion-Resistant Steel

NASM20615 Rivet, Solid, Universal Head, Brass, Copper, Nickel-Copper Alloy

2.2 Non-Government Documents

2.2.1 A-10 Program Specifications

G-R302 Process for Solvent Cleaning of Metals

G-F603 Blind Rivets, Installation of

G-F101 Deburring and Blending - Metals

2.2.2 A-10 Program Standards

SP664 Flush Fastenings — Structural (Rivets, Bolts. and Screws)

QATB M-40 (or equivalent)

Inspection of Holes in Fatigue and/or Fracture Critical Structures

2.2.3 Other Documents

2.2.3.1 All Fast Fastening Systems.

AF085 Rivet, Solid 100º Shear Head, Monel

2.2.3.2 Olympic Screw and Rivet Corp.

X4948 Rivet, Solid, 100º Shear Head, Monel

2.2.3.3 Rolex Fastener Corp.

R112 Rivet, Solid, 100º Shear Head, Monel

2.2.3.4 A-10 Program.

SM160M1000 Fatigue and Fracture Critical Parts List

3.0 REQUIREMENTS

3.1 Equipment

3.1.1 Equipment and tooling shall be suitable for and capable of performing the installation of rivets consistent with the requirements of this specification.

3.1.2 Equipment and tools for the inspection of the rivet installation must be capable of performing the specified function.

3.2 Materials

3.2.1 Solid and Tubular Rivets

All solid and tubular rivets shall comply with the respective part drawing listed under Section

2.0 for material and configuration, except as noted.

3.2.1.1 Cadmium plated rivets shall not be used in contact with titanium parts.

3.2.1.2 All solid aluminum alloy rivets, shall be finished in accordance with MIL-DTL-5541, Class 1A, color gold, unless otherwise permitted by procurring activity. Existing stocks of non-gold colored rivets may be used to depletion.

3.2.1.3 All solid rivets shall have radiused or chamfered ends. Square ended rivets are not acceptable. Existing stocks of square ended solid rivets may be used to depletion in hand installation only.

3.2.1.4 Plastic Film Tape No. 473T is a Product of 3M Company St. Paul, Minn.

3.2.2 Codes

3.2.2.1 Each rivet called out on a drawing will be represented by a basic code tabulated on the face of the drawing. Figure 1 is an illustration of the symbols and method of specifying the coding.

3.2.2.2 Code letters and other fastener installation requirements will appear within the rivet quadrant symbol used on the drawing and will be coded as illustrated in Figure 1.

3.2.2.3 Examples of coded rivet symbols:

Figure 1: Quadrant Symbols

3.2.3 Non Standard Grip Lengths

3.2.3.1 There are occasions where solid rivets are required in grip lengths other than standard .0625 incremental dash numbers. Certain rivet standards (Table I) have provisions for a .0312 increment between standard whole dash numbers. To eliminate confusion it shall be standard practice to call out the .0312 increment by using a third dash, -5 after the second dash number. Note that the designation shall be -5, not .5. Thus an MS20427M3-2-5 indicates a Monel rivet, 3/32 diameter, 5/32 grip length. See Figure 2.

Figure 1.1: Rivet Code

MS 20426

MS 20427

MS 20470

NAS 1097

TABLE I: NON STANDARD GRIP AVAILABILITY (1/32 INCREMENTS)

3.2.4 Substitutions

3.2.4.1 Hollow pull through 3/32 dia. blind rivets listed in G-F603, of equivalent grip length, may be used at the option of production to retain nut plates except in pressurized or fluid tight areas.

3.2.4.2 Substitutions shall be made according to the material type as shown in Table II.

3/32 Dia. Solid Rivet Type Specified on Drawing

Substitute 3/32 Diameter, Blind Hollow Pull Through Rivet

Aluminum Alloy Steel, CAD. Plate

Monel CRES

TABLE II: NUT PLATE RIVET MATERIAL

3.2.4.3 Hollow pull through blind rivets shall be installed in accordance with G-F603.

3.2.4.4 Alloy Steel Cadmium plated rivets shall not be used (or substituted) in areas requiring only non-magnetic materials.

3.2.4.5 Reference Sources for Rivet part numbers which are fully interchangeable are shown in Table III.

3.2.4.6 Table III shows acceptable alternates for the Olympic X4948 rivet which is not in currently in production.

TABLE III: ACCEPTABLE ALTERNATE RIVETS

Description Material Callout Olympic Allfast Rolex

Rivet, Solid 100º Shear Head

Monel 2/ X4948M 1/ AF085M R112 3/

Rivet, Solid 100º Shear Head

Monel CAD Plated

2/ X4948MP AF085M R112-( )-P-( ) 3/

1/ Olympic Rivet X4948 is not currently in production; unless stock is available an alternate must be used.

2/ Use supplier identification.

3/ Guardian Rivet and Fastener Inc., 35 Carlough Rd., Unit 1, Bohemia, NY 11716.

Manufactured by Genie Fastener Mfg., 35 Carlough Rd., Unit 1B, Bohemia, NY 11716.

3.3 Required Procedures and Operations

3.3.1 Fit-Up

3.3.1.1 All details shall be surface treated for corrosion protection as required by appropriate engineering drawing for that stage of assembly.

3.3.1.2 Parts shall be held together during hole preparation. There shall be no evidence of dirt or chips at the interface.

3.3.1.3 Remove all temporary coatings from mating and faying surfaces prior to assembly.

3.3.1.4 Flush head fasteners can be installed through temporary protective coating if rivet flushness requirements are met.

3.3.1.5 Vinyl tape (3M’s #473T) or suitable similar alternate can be used to hold preinserted rivets in place for riveting. Clean area of tape residue in accordance with G-R302.

3.3.1.6 All rivets may be installed at room temperature.

3.3.1.7 Burrs which could prevent seating of the fastener head shall be removed in accordance with G-F101.

3.3.1.8 Sealing compounds shall be applied to faying surfaces before riveting in the locations specified on the engineering drawings, and riveting shall be completed before the ‘work life’ expiration time of the sealant.

3.3.2 Holes

3.3.2.1 Fastener holes shall be drilled perpendicular within 2° to the surface against which the installed fastener head will bear. All (100%) structural holes prepared for the installation of fasteners in accordance with this specification shall, unless otherwise noted on the drawing, have a surface roughness of 125 RHR or smoother. See Table IV for acceptance limits.

Acceptable Not Acceptable

Circumferential scratches which are a minimum of 1/16” or 10% of the part thickness from the surface of the part, whichever is smaller.

Sprial scratches which are a minimum of 1/16” or 25% of the part thickness from the surface of the part, whichever is smaller.

Longitudinal scratches not more than 50% of length of the hole in any one part which neither start nor end within 1/16” or 25% of the part thickness from the surface of the part, whichever is smaller.

Any visible defect which does not exceed the specified surface roughness.

Scratches, nicks, or cuts intersecting a part of surface or exceeding limits specified as acceptable.

NOTE: Where Q.A.T.B. M-40 is referenced on the drawing, or is applicable to a designated hole or series of holes, the inspection requirements of Q.A.T.B. M-40 shall supersede the requirements of this document.

TABLE IV: SURFACE DEFECTS IN FASTENER HOLES

3.3.3 Hole-Sizes

3.3.3.1 Hole-sizes for protruding and flush solid rivets shall conform to Table V.

Recommended drill sizes are applicable to all rivets regardless of method of installation.

TABLE V: HOLE SIZES FOR SOLID RIVETS

Nominal Rivet Diameter

Fatigue and Fracture Critical

Non-Fatigue and Fracture Critcal

Recommeded Drill

Hole Diameter

Recommeded Drill Hole Diameter

1/16 # 51(.067) .066/.072

3/32 #41 (.096) .0961/.099 #40 (.098) .098/.103

1/8 #30 (.1285) .127/.130 #30 (.1285) .128/.134

5/32 #21 (.159) .159/.162 #20 (.161) .161/.166

3/16 #11 (.191) .190/.193 #11 (.191) .192/.198

1/4 1/4 (.250) .253/.256 F (.257) .255/.262

5/16 0 (.316) .315/.318 0 (.316) .316/.322

3/8 V (.377) .378/.381 V (.377) .379/.385

3.2.3.2 Hole sizes for tubular rivets shall be in accordance with Table VI.

TABLE VI: HOLE SIZES FOR TUBULAR RIVETS

Diameter

Actual Rivet Diameter

Recommended Drill Size

Hole Limits Diameter

Min. Max. Min. Max.

1/8 .118 .123 1/8 (.125) .125 .129

5/32 .141 .146 #26 (.147) .147 .151

3/16 .182 .188 3/16 (.1875) .188 .192

3.3.4 Rivet Lengths

3.3.4.1 Manufacturing shall select the correct undriven solid rivet length to allow sufficient material for forming the correct size driven head. Requirements are tabulated in Table VIII for the final dimensions of the shop driven head. Figure 2 and Table VIII also provide a guideline for determining the appropriate rivet length. See Figure 2.2 for guidelines for determining approximate rivet length where the formed head is on an incline.

3.3.4.2 Tubular rivets shall have the actual protrusion requirements tabulated in Table VII.

Nominal Protrusion

Rivet Dia.

1/8

5/32

3/16

Maximum

.09

.11

.14

Minimum

.06

.08

.11

TABLE VII: REQUIRED PROTRUSION BEFORE DRIVING TUBULAR RIVETS

3.3.5 Driving Procedure

3.3.5.1 Unless drawings show the direction of driving, the manufactured head may be located optionally on interior structure. It is desirable to form the shop driven head against the thicker sheet or harder metal.

3.3.5.2 The die or rivet set shall fit the manufactured head of the rivet. Exception: Flat dies may be used on universal head rivets where accessibility prohibits the use of universal head cupped dies. However, the flattened head dimensions of the universal head shall not be less than those values given in Table VIII.

3.3.5.3 Extreme care should be exercised when driving rivets in cast materials to ensure that they are not overdriven.

3.3.5.4 A reverse drive method (driving from the shank and bucking the head) may not be used in the production/procurement or repair of A-10 parts, unless qualified and approved by cognizant Air Force engineering organization, and will be considered only in limited applications where access may be an issue. The use of this reverse drive (tail drive, butt drive) method is depicted in Figure 1.2 for clarity, with the standard shop practice (head driven rivet) diagram shown in Figure 1.3. This process has been demonstrated to negatively impact the durability life of the riveted joint. Only the processes and methods controlled by A- 10 approved program specifications and A-10 drawings are permitted to be used in the manufacture and maintenance of A-10 parts and assemblies.

Figure 1.2: Depiction of Unacceptable Reverse Drive Method

Figure 1.3: Standard Shop Practice (Head Driven Rivet) Diagram

3.3.6 Shop Driven Heads

3.3.6.1 All rivets shall be driven to a minimum head diameter of 1.3 times the shank diameter not to exceed 1.4 times the shank diameter. Table VIII lists the acceptable driven head dimensional limitations.

Diameter, in.

A * Head Diameter, in.

B * Head Thickness, in.

C * Approximate Length to Form Head, in. Minimum Maximum Minimum Maximum

1/16 0.081 0.087 0.025 0.04 0.094

3/32 0.122 0.131 0.038 0.05 0.141

1/8 0.163 0.175 0.05 0.07 0.188

5/32 0.203 0.218 0.062 0.092 0.234

3/16 0.244 0.262 0.075 0.105 0.281

1/4 0.326 0.35 0.082 0.112 0.375

5/16 0.425

(0.380) 0.437

(0.411) 0.089

(0.140) 0.120

(0.186) 0.468

3/8 0.500 (†) 0.525 (†) 0.102 (†) 0.160 (†) 0.563

GENERAL NOTE: Driven head thicknesses greater than the maximum value in table will be acceptable for a maximum of 5% of the rivets in a joint.

* See Figure 2.

( ) Monel-type rivets only. To meet required height and diameter requirements, install using approximately 2–3 grip lengths shorter than recommended for standard rivets.

† Consult engineering for further disposition.

TABLE VIII: STANDARD FLAT DRIVEN HEAD DIMENSIONS — SOLID RIVETS

3.3.6.2 When required, shop driven universal heads may be formed using the next smaller size universal head riveting die (i.e., 1/8 die for 5/32 rivet). Shop driven universal heads shall conform to the values tabulated in Table VIII and Figure 2 for the rivet diameter.

Figure 2: Driven Head

3.3.7 Flush Driven Heads

3.3.7.1 Flush Driven Heads shall be in accordance with SP664 for the following rivets unless otherwise specified on the engineering drawing: MS20426, MS20427, NAS1097, NAS1199, NAS1200 or X4948M (R112, AF085).

Figure 2.1: Angular Rivet Installation

3.3.7.2 Angularity — Rivet driven heads may be formed on 15° maximum incline for aluminum alloy rivets, and on a maximum incline of 7° for steel and monel rivets. See Figure

2.1 and Table VIII.

3.3.7.3 Washers — Washers are used only when specified by the appropriate engineering drawing.

3.3.8 Nut Plate Installation

3.3.8.1 The minimum driven head diameter shall be in accordance with Table VIII and the head height shall be a minimum of .010 inch above the surface of the nut plate. Slight clinching of the rivet is acceptable provided the minimum head dimensions are met. (See Figure 6.)

Figure 2.2: Nut Plate Installation

3.3.9 Automatic Riveting

3.3.9.1 The use of automatic riveting in accordance with this specification requires approval by the A-10 procuring authority and/or cognizant engineering authority. Automatic riveting shall not be accomplished on parts listed in the fracture and fatigue critical parts list, SM160M1000 unless authorized by the engineering drawing. Suppliers proposing to use automatic riveting must submit a qualification plan and specification to the cognizant A-10 Air Force authority for approval. The specification must include a description of the process, including a list of all equipment needed to produce holes meeting the hole quality criteria on A-10 drawings for rivet installation and this specification. Suppliers’ plan and specification shall provide details of testing both drilled only and drilled and riveted samples. Samples shall be representative of the actual structure or geometry that automatic riveting will be qualified for and used in production once fully qualified. Suppliers shall submit results of qualification for the particular automatic riveting application(s) proposed to the A-10 procuring and cognizant engineering authority for approval. Once test articles are qualified and a process has been determined, a specification shall be prepared/finalized to control the automatic hole drilling and automatic hole drilling/riveting process. The specification must call out acceptance and qualification procedures for operators, process qualification, recurring equipment qualification, production acceptance, sealant/primer application, as well as general operating requirements. In addition, the proposed specification must have a Quality Assurance section that defines process qualification, recurring equipment qualification and production acceptance and qualification. The supplier’s specification, which may be an already existing internal supplier’s document, must be approved by the cognizant A-10 authority, prior to any A-10 Production.

3.3.9.2 Multiple (Gang) and Drivmatic Riveting. — The height of manufactured heads after riveting shall not be less than the values in Table IX.

Nominal Rivet Diameter Driven Head Height

1/8 .042

5/32 052

3/16 .062

1/4 .083

5/16 .104

3/8 .125

TABLE IX: MINIMUM DIMENSION FOR MANUFACTURED HEADS OF

UNIVERSAL RIVETS (DRIVMATIC AND GANG RIVETING)

3.3.9.3 For rivets driven in automatic riveting machines, limits on marking of driven heads caused by wear of the locating pin are shown in Table X. This mark shall not extend below the top of the driven head.

Nominal Rivet Diameter Height Above Head

1/8 .005

3/32 .010

5/32 .015

3/16 .020

TABLE X: LIMITS, HEAD MARKS AUTOMATIC RIVETING

3.3.9.4 Rings caused by the punch of automatic riveting machines are acceptable when they are even or above the surface of head, see Figure 2.3 or if they are below the surface of the head a maximum of 0.010 inches for heads having a minimum height of 4 times the diameter.

See Figure 2.4.

Figure 2.3: Punch Ring

Figure 2.4: Depressed Punch Ring

3.3.10 Head Flushness

Head flushness shall be in accordance with blueprint requirements.

3.3.11 Shaving

3.3.11.1 When shaving solid rivets is permitted by drawing, including rivets in tanks and pressurized sections, surface flushness requirements shall be per Table XIII.

3.3.11.2 Head protrusion shall not exceed “H” in Table XI after driving and prior to shaving.

3.3. 11.3 Head diameter shall not be less than “D” in Table XI after shaving

TABLE XI: DIMENSIONS — RIVETS SHAVING 100° HEADS

Nominal

Rivet Diameter

3/32 1/8 5/32 3/16 1/4 5/16 3/8

H

Maximum Head

Protrusion Prior to Shaving

.006 .007 .009 .010 .012 .014 .016

D

Minimum Head

Diameter after

Shaving

.161

.204

.262

.326

.443

.526

.650

3.3.11.4 The sheet surface shall not be damaged by the shaving tool. (Adjust the stop of the shaver so that it extends .001 to .002 beyond the cutter and test this setting prior to use.)

3.3.11.5 NAS1097, NAS 1200, X4948, R112, and AF085 rivets shall not be shaved.

3.3.11.6 See SP664 for double flush (flush both sides) rivets.

3.3.12 Oversize Rivets

The use of NAS1241 and NAS1242 repair rivets is applicable when called out on new production or modification drawings.

3.4 Recommended Procedures

3.4.1 Rivet Removal

3.4.1.1 Center punch on the center of the manufactured head. Apply a drill of the same size as the rivet hole-size to the punch mark. Then drill through the manufactured head of the rivet up to the skin.

3.4.1.2 If the structure is light, back up the rivet with a bucking bar while center punching.

3.4.1.3 Break off the head by inserting a pin punch in the drilled portion of the rivet and exerting a prying motion on the pin punch. Then punch out the rivet shank while supporting the opposite side of the structure.

3.4.2 If the rivet hole is still within acceptable limits, install a new rivet of same type and material. If the hole is oversize, then proceed in accordance with standard procedures for defects.

3.4.2.1 Oversize NAS1241 and NAS1242 Solid Repair Rivets may only be used when called out on A-10 drawings or dispositioned through authorized MRB activity.

4.0 QUALITY ASSURANCE

4.1 Manufacturers’ tolerances on the heads of flush head fasteners may result in partially exposed countersinks. Exposed areas around the fastener head are acceptable if the fastener tolerances, hole-tolerances, and flushness requirements are met. (See Figure 3.)

Figure 3: Exposed Countersink

4.2 Gaps Evaluation

Gaps shall be evaluated in accordance with the following:

4.2.1 There shall be no measurable gap under the shop driven head of an installed solid shank rivet.

4.2.2 The manufactured heads of all universal head fasteners shall seat such that a .002 inch thick shim does not contact the fastener shank when inspected as shown in Figure 5(a) and (b). Contact with the shank is indicated when the shim does not wedge and will slide freely under the head as shown in Figure 5(b).

4.2.3 The manufactured heads of all flush head fasteners shall seat such that a .002 inch thick shim cannot be inserted between the fastener head and the countersink for more than 40% of the circumference of the head and .002 inch thick shim, of the configuration shown in Figure 4, does not contact the fastener shank when inspected as shown in Figure 5(c) and (d).

Figure 4: Shim Configuration

Figure 5: Flush Head Seating Check

Shim wedges and does not move freely in this direction

Figure (a)

Shim contacts shank or moves freely in this direction

Figure (b)

Shim wedges light force and requires for removal

Figure (c)

Shim stops suddenly when contacting shank and is not wedged

Figure (d)

4.3 Acceptance Limits

The standards given below are minimums that apply to a small percentage (5%) of the rivets in a joint. They are not a basis for acceptance of larger percentages of rivets with these defects.

4.3.1 Driven Heads

4.3.1.1 Clinched, club, or bent-over heads as in Figure 6 are due to poor workmanship or poor alignment of riveting dies. They shall be rejected where the hole, or a chamfer made in deburring the hole, is visible. Heads driven on dimples shall show no evidence of the hole.

Figure 6: Clinched Head Solid Rivet — Not Acceptable

4.3.1.2 Bell shaped driven heads as in Figure 7 are formed by use of too light a bucking bar and/or by “rocking” the bucking bar. Rivets whose head shape is approximately the same or worse than the illustrated case shall be rejected since the rivet hole is poorly filled and the head has very little bearing surface on the sheet.

Figure 7: Bell Shaped Head — Not Acceptable

4.3.1.4 Cut of round driven heads should be judged by the minimum diameter. Tipped heads are acceptable if the head thickness does not exceed those values of Table VIII. Heads cut due to slipping of the bucking bar shall be judged according to the apparent weakening of the head. See Figure 8.

Figure 8: Tipped and Cut Head

4.3.1.5 Clinched heads of tubular rivets shall be well formed and flush with the face of the sheet. (See Figure 9.)

Figure 9: Clinched Heads Tubular Rivets

4.3.2 Cracked Driven Heads

4.3.2.1 Diagonal Cracks

4.3.2.1.1 Cracks on the sides of driven heads which run at a 450 angle to the flat surface of the head are caused by upsetting the rivet material beyond the limit of its ductility. 2017 rivets are driven in a hard condition so special care must be taken to keep the driven head as close as possible to 1.3 diameter, to avoid cracks.

4.3.2.1.2 For aluminum alloy rivets diagonal cracks shall be evaluated as follows: (See Figures 10, 11 and 12.)

Figure 10 — Hairline or superficial cracks are negligible in all cases regardless of their numbers. Intersecting superficial cracks are also acceptable.

Figure 11 — Rivets having diagonal cracks which do not intersect are acceptable. The maximum number shall be three (3).

Figure 12 — Rivets with severe cracks as shown in Figure 12 are not acceptable and are to be replaced.

Figure 10: Acceptable Diagonal Cracks

Figure 11: Acceptable Diagonal Cracks

Figure 12: Unacceptable Diagonal Cracks

4.3.2.2 Diagonal Cracks (2017 Rivets only). — For 2017 aluminum alloy rivets the criteria as specified for diagonal cracks shall apply as modified herein.

4.3.2.2.1 For 2017 aluminum alloy rivets, diagonal cracks shall be evaluated as follows: (See Figures 10, 11, 12 and 13).

Figure 10 — Hairline or superficial cracks in the formed heads of rivets are acceptable regardless of number providing that, when this cracking condition occurs continuously, riveting operations are investigated for possible errors in rivet heat treat condition or rivet lengths.

Figure 11 — Rivets having diagonal cracks which do not intersect or which do not extend into the flat portion of the driven head are acceptable. The maximum number of cracks in any rivet shall be five (5). IN ADDITION, rivets having diagonal cracks which extend into but do not intersect on the flat portion of the driven head, as shown in Figure 11, are acceptable if there is no more than one rivet with this condition in any three consecutive rivets.

Figure 13: Unacceptable Face Cracks

4.3.2.3 Vertical Cracks

4.3.2.3.1 There are two types of vertical cracls; one caused by a lap in rivet wire, and the other caused by overheat treating of the rivets. It is important to distinguish between these two types.

Figure 14 — Cracks due to lap in rivet wire appear infrequently. The surface exposed by the cracks will be smooth and dull in appearance and will be only a few thousandths deep. (.005 – .015). These cracks are acceptable.

Figure 15 — When cracks from overheating appear, they are usually found in a large percentage of the rivets being driven. This cracking is due to excessive temperatures being reached during the heat treatment of the rivet.

These cracks are not acceptable and rivets having these vertical cracks on either head shall be rejected. The batch which was overheated should be segregated and scrapped since the ductility cannot be restored by reheat treatment.

Figure 14: Acceptable Vertical Cracks

Figure 15: Unacceptable Vertical Cracks

4.3.2.3.2 Radial cracks in clinched heads of tubular rivets as shown in Figure 16 are acceptable.

Figure 16: Radial Cracks, Tubular Rivets

4.3.3 Manufactured Head (as Received From Rivet Supplier)

4.3.3.1 If a rivet set is used, with too small a cupping radius, which does not make initial contact at the peak of the head (see Figure 17); the shank drives up into the manufactured head and forms a lap or it can crack at the head to shank junction. All rivets showing a mark indicative of the above shall be replaced whether the mark is a partial or a complete circle indented in the manufactured head.

NOTE: The manufactured head shall not be reworked (sanded, ground, filed, etc.), in any manner, in order to meet this requirement.

Figure 17: Head Marks, Small Die

4.3.3.2 Use of too large a die usually results in the edge of the die deforming the sheet around the rivet. (See Figure 18.) No serious damage is done to the rivet itself in most cases.

Figure 18: Head Marks, Large Die

4.3.4 Damage to Sheets

Dents or scratches made by bucking bars or rivet sets cannot be classified and each case must be judged as to the degree to which the strength and/or corrosion resistance of the part has been impaired.

4.3.5 Shanked Rivets-Part Separation

4.3.5.1 A maximum of .015 inch shanking (part separation) is permissible for the rivet adjacent to intermediate material as illustrated in Figure 19.

Figure 19: Shanking, Intermediate Materials

4.3.5.2 A maximum of .015 inch shanking (part separation) is permissible for a rivet in a joggle area when tapered fillers are used. (See Figure 20.)

Figure 20: Shanking Joggled Parts

4.3.5.3 A maximum of .015 inch shanking (part separation) is permissible for a rivet in the joggle area when both parts of the structure are joggled. (See Figure 21.)

Figure 21: Shanking, Double Joggled Parts

4.3.5.4 Except in cases 3.4.3.1 through 3.4.3.3 above, if a .002 inch shim can be slid between the riveted parts to contact the rivet shank, the rivet shall be rejected for shanking.

5.0 PREPARATION FOR DELIVERY — NOT APPLICABLE