DMC:V2500-00-70-39-03-00A-624A-D|Issue No:002|Issue Date:2019-02-01

Export Control

EAR Export Classification: Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3), except for the following Service Bulletins which are currently published as EAR Export Classification 9E991: SBE70-0992, SBE72-0483, SBE72-0580, SBE72-0588, SBE72-0640, SBE73-0209, SBE80-0024 and SBE80-0025.

Copyright

© IAE International Aero Engines AG (2001, 2014 - 2021) The information contained in this document is the property of © IAE International Aero Engines AG and may not be copied or used for any purpose other than that for which it is supplied without the express written authority of © IAE International Aero Engines AG. (This does not preclude use by engine and aircraft operators for normal instructional, maintenance or overhaul purposes.).

Applicability

All

Common Information

TASK 70-39-03-390-501 Riveting

General

Most rivets are formed by a cold continuous squeeze procedure. With this procedure hand tools, hydraulic or pneumatic machines, are used to form the rivet heads with a continuous squeezing operation. Special tools, anvils and rivet sets, are also supplied when necessary. The hydraulic cold riveter is usually recommended, more than the pneumatic riveter, because it can apply higher pressures which are frequently necessary. For special uses (for example, swaging, bucking, hot forming of rivets, the use of dimpled sheets or explosive rivets), special instructions are given in the related assembly instructions.

In most cases, the correct replacement rivet for an assembly, is specified in the related Engine Illustrated Parts Catalog (EIPC) and/or the assembly instructions. Use the instructions given in this section for the correct replacement of oversized rivets when EIPC and assembly instructions are not given.

The specifications that follow, give the conditions that are applicable to the removal and replacement of rivets in riveted assemblies. Some assembly conditions specify modifications to these specifications. Where there are differences, between these specifications and the assembly data given in the related engine instructions, the engine instructions must be obeyed.

NOTE

Rivets made of AMS 7223 aluminum alloy (icebox rivets) must have a special treatment, before use, to prevent cracks when they are formed. They must be solution heat treated at 900 F to 920 F (482 C to 493 C) for 20 to 30 minutes, then immediately put into cold water. The rivets must then be kept in a freezer, at 0 F to -40 F (-18 C to -40 C), until they are to be used.

Preliminary Requirements

Pre-Conditions

NONE

Support Equipment

NONE

Consumables, Materials and Expendables

NONE

Spares

NONE

Safety Requirements

WARNING

IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURERS MATERIAL SAFETY DATA SHEETS FOR CONSUMABLE MATERIALS. THESE CONTAIN INFORMATION SUCH AS, HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, HEALTH HAZARD DATA, PRECAUTIONS FOR SAFETY HANDLING, USE AND CONTROL MEASURES AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION.

Procedure

1. CAUTION
  BLIND RIVETS MUST NOT BE DEGREASED OR SOLVENT WASHED AS THIS WILL REMOVE THE LUBRICANT.
  Blind bolt: A blind bolt is a three-piece assembly (that is, a sleeve, a nut-type of expander and a core bolt). This assembly is installed and set (that is, when the sleeve is expanded by the nut) with special tools that are from the side of the sheet on which the manufactured head of the sleeve is installed. The core bolt is installed after installation of the sleeve.
2. Blind rivet: A blind rivet is a rivet installed and set (with the upset head formed) from the same side of the sheet, on which the manufactured head is installed. The rivets are made of different parts, which are set when integral pins or stems are pulled with a special tool. Different types of blind rivets are available in which the pins are broken-off above, below or flush with, the manufactured head. While with other types of blind rivets, the pins are pulled fully through and away from the shells of the rivets.
3. Burr collar: A burr collar is a thin irregular shaped ridge of material around a rivet hole that is the result of a machining or piercing operation.
4. Counter surface: The surface of the recess, in the shape of a cone, used for countersunk head rivets. The surface is made by machining or dimpling.
5. Faying surface: A surface that makes close contact with a different surface. An attached surface.
6. Impacted burr collar: An impacted burr collar is one that is pushed away from the rivet hole or is caught by the rivet in the upsetting operation.
7. Machine countersunk: This shows that the holes were drilled through all sheets in one operation; also that the countersink depressions were made by a machine operation, that cut the metal - (Refer to Figure). Machine countersinks are usually contained in one sheet and do not go through to the faying surfaces.
8. Manufactured head: The head made when the rivet was made and before the rivet was installed in the assembly.
9. Protruding head rivet: A protruding head rivet is a rivet with the bearing surface of its head flat against the sheet; where its full head is above the surface of the sheet. Protruding head is a general name. This includes button, brazier, cone, fillister, flat, mushroom, oval, pan, round, steeple, tinners, truss, universal or washer head shapes.
10. Rivet pin: A rivet with a circumferential groove, or grooves, on the opposite end to the head. After the pin is installed, a collar or sleeve is swaged, over the end of the pin, into the grooves. This gives the same hold effect, as the upset head on a conventional rivet.
11. Rotating or revolving part: A part that rotates (turns) about its own axis or a part that is attached to a part that rotates around its own axis.
12. Sheet: A metallic or plastic item, in which the rivet is installed, that has been machined, forged, rolled, or molded to be thinner than its length and/or width.
13. Static part: a stationary part (that is, any item other than a rotating or revolving part).
14. Upset head: The head made when the rivet is installed into the assembly.
15. Wetted surface: The surface of the sheet, or part, above which the fluid, such as air, flows.
1. 1. The dimensions of the rivet hole must be as specified in Figure, unless specified differently in Step.
2. 1. Unless specified differently, as in Step, the rivet holes must be made during assembly although pilot or rigging holes are permitted. All unwanted materials, between the sheets which can cause separation of the sheets, must be removed before riveting. If it is found that the riveting procedure (that is, manual or automatic) causes a clamping effect, that does not let unwanted materials become caught between the sheets, separation of the sheets for cleaning will not be necessary. The perpendicularity must not be more than 5 degrees (for diameters up to 0.250 in. (6.35 mm)), or 3 degrees (for diameters more than 0.250 in. (6.35 mm)).
  2. Rivet holes for attached or free-to-move anchor nuts, gang-channel nut assemblies or other fasteners (that is, for a hold effect during assembly), can have the holes drilled in detail or at assembly.
  3. There can be separation of the rivet parts after drilling and before riveting, when the parts are identified. This is to make sure that the parts and holes are aligned the same at riveting as when drilled.
  4. For rotating or revolving parts, the holes must be smooth (without burrs to prevent seating of the rivets, or separation of the sheets) with a 0.005 in. (0.13 mm) maximum broken edge. This is usual for penetrated edges.
  5. For static parts, unless specified differently, a burr collar is permitted; if the instructions given in step 3.F. and Step, step 6.B. are obeyed. If deburring is necessary, the edges can be broken a maximum of 0.005 in. (0.13 mm).
3. 1. The counter surface for rivets must be such that a good fit is made with the manufactured rivet head; also that the manufactured head is flush to high before driving. Unless specified differently, the manufactured rivet head must be minus 0.000 in. (0.00 mm) to plus 0.005 in. (0.13 mm) high after driving. If the upset head is set into a countersunk or chamfered hole, the upset head must be flush to 0.020 in. (0.51 mm) above the surface. The manufactured heads of driven rivets, that are plus 0.005 in. to 0.010 in. (0.13 mm to 0.26 mm) high, must be shaved to minus 0.000 in. (0.00 mm) to plus 0.005 in. (0.13 mm) high. Where flush is specified on the assembly instructions, manufactured (or upset) heads must be shaved to minus 0.000 in. (0.00 mm) to plus 0.0005 in. (0.01 mm) high. (See Figure). Rivets that are plated (cadmium, etc) for corrosion protection must not be shaved to obtain flushness requirements. The inspection is usually done before shaving. The limits specified in Figure and Step, step 6.H., must be used. This is to find if too much material has been shaved from the rivet head. If flushness is produced by grinding, no burns are permitted.
  2. Where flush is specified on the assembly instructions, the manufactured head of rivets used to retain anchor (or plate) nuts may be set at 0.000 in. (0.00 mm) to minus 0.005 in. (0.13 mm) below the sheet surface or shaved to produce a flush requirement.
  3. The necessary hole and recommended counter surface dimensions are given in Figure and Figure. The counter surface dimensions can be different, to get the correct flushness of completed rivet.
  4. Unless specified differently, the counter surfaces must be smooth. They must be free from burrs, cracks, or vibration marks, and concentric to the rivet hole to less than 0.005 in. (0.13 mm) FIR.
  5. NOTE
    In plastic sheet, the nominal angle of the counter surface can be decreased by three degrees from the nominal angle of the manufactured rivet head.
    Counter surface types:
    Machine countersink for manufactured head: When the counter surface is made by machine countersinking (Symbol - C), the dimensions of the completed hole must be as specified in Figure. The counter surfaces must be as specified in Figure. The countersink must not go through the top sheet.
    Machine countersink for upset end: When it is necessary to upset the end of the rivet (into the machine countersink), the dimensions of the completed hole must be as specified in Figure. The 82 degree counter surface must be as specified in Figure.
  6. Flush blind rivets, blind bolts and rivet pins:
    The manufactured heads of blind rivets, blind bolts and rivet pins, must be minus 0.005 in. (0.13 mm) to plus 0.010 in. (0.26 mm) high after driving. The manufactured head must not be damaged, to get the correct flushness. Where flush is specified on the assembly illustration, the manufactured head must be shaved to plus 0.0005 in. (0.01 mm) high. Figure must be used, to find if too much material is shaved from the rivet head. For alternative instructions, refer to Step, step 6.J.(2).
4. 1. Hole dimensions:
    The hole dimensions, for protruding head rivets, must be as specified in Figure.
  2. Direction of assembly:
    The direction of assembly is optional, unless specified differently on the assembly illustration or in the assembly instructions. In general, the upset head is on the same side as the thicker skin or harder material.
    A dash is used for the upper line in the lower left quadrant as there is no countersink necessary with this head style.
5. 1. The nominal distances between the rivets, and from the edges, must be as specified on the assembly illustration. The rivet holes must be in the correct position; with a radius of 0.030 in. (0.76 mm) and/or a run of 0.060 in. (1.52 mm). Mismatch between corresponding holes must not be more than 0.001 in. (0.025 mm).
  2. Table Figure gives the minimum inspection and edge distances, for the riveted assemblies. These limits can be different, when permitted in Step, step 6.F.
  3. When the length of a rivet run, with equal distances, is controlled by the end holes the part length will be different; for each assembly. When this occurs, it will be necessary to change the distance at the end of the run; so that most of the holes can be found, with templates of the drill jigs. The distance can be increased or decreased, by a maximum of 0.060 in. (1.52 mm.) for as many distances as necessary, to make the end holes into an equal shape; when the minimum dimensions given in Figure are obeyed.
6. 1. Nominal faying surfaces - (Refer to Figure):
    Unless specified differently, as in steps (2) thru (4) that follow, the maximum clearance between all faying surfaces in a riveted assembly (where a clearance is not specifically permitted), in a diameter equal to two times the manufactured head diameter, will be 0.001 in. (0.02 mm). For sheet metal components the maximum gap of 0.001 in. (0.02 mm) must apply within one manufactured head diameter. The maximum clearance (sheet separation) between the rivets, more than the distance given above, will be as follows:
    For distances between rivets (which are up to and include 23 times the nominal thickness of the thinnest sheet), the maximum clearance is 0.010 in. (0.25 mm).
    For distances between rivets (which are 24 or more times the nominal thickness of the thinnest sheet), the maximum clearance is 0.020 in. (0.51 mm).
  2. Parts with anchor nut plates riveted to convex surfaces - (Refer to Figure - Detail A):
    For a diameter equal to two times that of the manufactured rivet head, a maximum clearance (sheet separation) of 0.010 in. (0.25 mm) is permitted; when the line contact specified in Step, step 6.B.(5)(b)(ii) is kept. After this point, the clearance will decrease; until there is no clearance at the center point between rivets.
  3. Parts with anchor nut plates riveted to concave surfaces - (Refer to Figure - Detail B):
    For a diameter equal to two times that of the manufactured rivet head, a maximum clearance (sheet separation) of 0.003 in. (0.08 mm) is permitted; when the line contact specified in Step, step 6.B.(6)(b)(ii) is kept. The maximum permitted clearance, at a center point between the rivets, is 0.010 in. (0.25 mm).
  4. Parts with plastic details (which include reinforced plastics):
    For a diameter equal to two times that of the manufactured rivet head, a maximum clearance of 0.005 in. (0.13 mm) is permitted, when there is a line contact between the sheet surface and the rivet head; for the full head diameter, in at least one plane, that contains the rivet axis. If the manufactured rivet head touches a convex plastic sheet, a minimum of two contact points - (Between the head and the sheet) must be kept.
7. 1. When the rivet length is specified in the rivet symbol - (Refer to Step, step 5.B.(3)), the length is for reference only. It can change during assembly, when necessary, if the limits given in Step are kept. Rivets made of titanium base alloys must not be cut, to get the necessary length.
  2. Usually, the rivet length is equal to the nominal thickness of the assembly, plus 1.5 times the nominal rivet diameter to the nearest fractional equivalent in 16ths of an in..
8. 1. The manufactured head of the rivet must not exceed on to the radius of the bend - (Refer to Figure - Detail B).
  2. The upset head can extend on to the radius of the bend by the amount B given in Figure. Refer also to Figure.
  3. The minimum distance from the bend radius to the rivet hole axis, distance C in Figure, must not be less than 0.5 times the rivet diameter.
1. 1. The holes necessary for such rivets must be as specified in the assembly instructions. The counter surface, when necessary, will be as specified in Figure.
  2. Blind rivets must be used in the as received condition. These rivets are lubricated by the manufacturer. Heat, the removal of grease, or cleaning with a solvent will cause the lubricant to have unsatisfactory performance and thus make the rivets unsatisfactory for use.
  3. Blind rivets which are dented, nicked, dirty, mixed, lubricated again, damaged or repaired must not be used.
  4. One type of rivet must not be changed for a different type of rivet. The selection of longer or shorter grip range rivets, for the necessary grip length, is not permitted unless specified in the assembly instructions.
2. 1. The holes and counter surfaces necessary, for the rivet pins, will be specified in the assembly instructions.
  2. One type of rivet pin must not be changed for a different type of rivet pin.
3. 1. When specified on the assembly illustration, the broken ends of the blind rivets and rivet pins must have a protective treatment applied. This treatment must be done as soon as possible after the installation of the rivet or pin.
1. 1. On the rivet assembly illustrations the type of rivet, head position, type of hole and necessary counter surface are specified by the use of standard symbols. The symbol includes a single cross, which shows the location of the fastener - (Refer to Figure - Detail A).
2. 1. Upper left quadrant:
    NOTE
    Codes that start with X, Y or Z are only for Pratt and Whitney use.
    The identification of a rivet is by a part number - (Refer to Figure - Detail B) or by a letter code, in the upper left quadrant - (Refer to Figure - Detail C). Refer also to Figure, Figure, Figure and Figure.
  2. Upper right quadrant - (Refer to Figure):
    The rivet diameter and location of the manufactured head are shown in this quadrant by an alpha-numeric code that follows.
    The number gives the rivet diameter, in 32nds of an in..
    The letter gives the position of the manufactured head.
    NOTE
    No letter is included in the code, when the location of the manufactured head is optional; or when it is specified differently, on the assembly illustration.
    If not specified, the direction of assembly is optional. In general, the upset head is on the side of the thicker sheet or harder material.
    F equals far side and N equals near side. The side to which the arrow points, is the near side.
  3. Lower right quadrant - (Refer to Figure - Detail C):
    The recommended rivet length is specified, in this quadrant, when a letter code is shown in the upper left quadrant. When the length is specified, if it is for reference only - (Refer to Step, Step).
  4. Lower left quadrant - (Refer to Figure - Detail D):
    The sheets to be countersunk are shown in the lower left quadrant; by the number-letter code that follows:
    The letter C is used to show a machined countersink operation. Unless specified differently, in this quadrant, the countersink angle will be the same as the manufactured head angle.
    Rivets that are flush on each side are shown with the number-letter code on two different lines. The first line shows the countersink operation for the manufactured head; while the second line shows the countersink operation for the upset head. If the angle is different, from the manufactured head, the included angle will be shown as in Figure - Detail B; but without the degree symbol.
    The word FLUSH is included in this quadrant - (Refer to Figure) where the close flushness requirement of Step, Step applies.
    All other codes shown in this quadrant will have special preparation instructions.
  5. Drawing symbol summary:
    Upper left quadrant: The identification of rivets by part number or letter code, is shown in Figure, Figure, Figure, Figure or on the assembly illustration.
    Lower left quadrant: When specified, a dash in the upper line signifies that countersink is not required on manufactured head. Letter C shows machine countersink preparation. All other codes have special instructions.
    Upper right quadrant: Number equals rivet diameter in 32nds of an in. - (Refer to Figure). Location of manufactured head: F equals far side and N equals near side. When no letter is shown, head location is optional (Refer to Step).
    Lower right quadrant: Reference length of rivet only applies when letter code is shown in upper left quadrant - (Refer to Step, Step).
1. 1. All holes and countersinks must be held in their basic locations; not more than 0.030 in. (0.76 mm) from the true position unless permitted in Step, Step, and must be free from cracks.
2. 1. General:
    The upset head must have the necessary dimensions given in Figure and Figure - Detail A.
    For rivets made of materials not specified in Figure, use the values specified in that Figure.
  2. Concentricity:
    The upset head of the rivet may be eccentric to the shank, if the shank can not be seen.
  3. Damaged upset heads:
    The upset head can be damaged, as shown in Figure - Detail B; if, for each rivet, the measured difference between the minimum and maximum head height, is not more than the values given in Figure. A head that is damaged, other than that permitted in the specifications, can not be accepted.
  4. Stepped heads:
    The upset head can be stepped, because of an offset driver or bucking bar, if the stepped part is not less than the minimum head thickness and the high part is not more than the maximum head thickness given in Figure - (Refer to Figure - Detail C).
  5. Flat manufactured heads:
    The manufactured heads of protruding head rivets can be flat, because of a flat driver or bucking bar - (Refer to Figure - Detail B), if the head is not thinner than the minimum head height for upset heads - (Refer to Figure); for all materials. Rivets with manufactured head heights of less than these values, before driving, must not be flat.
  6. Open heads on flush and protruding head rivets - (Refer to Figure - Detail D):
    Solid rivets: The clearances between the rivet manufactured and upset heads, of installed shank rivets and the surface of that part being riveted, will be found as follows:
    There must be no clearance below the upset head of an installed solid shank rivet.
    The manufactured heads of all protruding head rivets must be such that a 0.002 in. (0.05 mm) shim can not touch the rivet shank; when examined as shown in Figure - Details A and B. A contact with the rivet shank is found, when the shim does not touch and can move freely; below the rivet head - (Refer to Figure - Detail B).
    The manufactured heads of all flush head rivets must be such that a 0.002 in. (0.05 mm) shim can not be put between the rivet head and the countersink; for more than 145 degrees of the circumference of the head - (Refer to Figure - Detail A). Also, that a 0.002 in. (0.05 mm) shim - (Almost the same as the type shown on Figure) does not touch the rivet shank; when examined, as shown on Figure - Details A and B.
    Rivets with clearances 0.002 in. (0.05 mm) or less below the upset head, must be hit again. Rivets with clearances of more than 0.002 in. (0.05 mm) must be replaced. Rivets with clearances between the manufactured head and the sheet, more than the limits specified in Step and Step, must also be replaced. At least 50 percent of the manufactured head must have a zero clearance with the sheet.
    Blind and hollow rivets, bolts and rivet pins:
    Flat surfaces: For protruding head rivets, bolts and pins, a 0.005 in. (0.13 mm) maximum clearance is permitted - (Between the manufactured head and the flat sheet surface); when at least 40 percent of the head circumference touches the sheet surface. For countersunk manufactured heads a 0.003 in. (0.08 mm) maximum clearance is permitted - (Between the rivet head and the countersink); when there is no clearance, for at least 50 percent of the rivet head circumference - (Refer to Figure).
    Curved surfaces: Protruding head rivets, bolts and pins, set in curved surfaces can have a clearance around the head circumference; when there is a line contact, between the sheet surface and the rivet head - (For the full head diameter), in at least one plane that contains the rivet axis.
    Plastic sheets:
    The instructions given in Step above apply to solid rivets, in assemblies that contain plastic or reinforced plastic sheets.
    Rivets used to attach anchor nuts and gang-channel nuts:
    The rivets used to attach anchor nuts and gang-channel nuts must be tight, after they are installed. The clearance checks, specified in Step thru Step above, are not necessary. The instructions given in Step, Step and Step, must be obeyed.
  7. Flush heads:
    Flush head rivets installed below the surface of the sheet, before or after driving, can not be accepted.
    Rivets that are plated, for corrosion protection, must not be shaved; to get the necessary flushness.
  8. Cracks:
    CAUTION
    RIVETS MADE OF SOME MATERIALS, SUCH AS AMS 7223, MUST BE KEPT AT A LOW TEMPERATURE, UNTIL USED, TO PREVENT PRECIPITATION HARDENING, BEFORE THE USUAL TIME, WHICH CAN CAUSE CRACKS IN THE UPSET HEADS.
    Manufactured heads:
    No cracks are permitted, in the manufactured head of the rivet.
    Upset heads:
    Some cracks are permitted, in the upset heads, when they are not more than the limits given on Figure. Cracks are not permitted in more than 10 percent of a rivet pattern. Cracks are not permitted in rivets made of AMS 7223 material.
    Rivets with cracks around the edge of the upset head, that run in an approximate radial direction, can be accepted; if they do not go into diameter A, or are not longer than length B - (Refer to Figure).
    The width of a crack must not be more than 0.062 times the shank diameter - (Refer to Figure).
    Cracks in locations of the upset head, other than those shown on Figure, can not be accepted.
    Rivets with cracks around the edge of the upset head, in the shape of a wedge - (Such that a chip can fall out), can not be accepted - (Refer to Figure - Detail A).
    Cracks in the swaged or flared end of hollow rivets can not be accepted.
  9. Manufactured head set damage:
    Protruding head rivets:
    Protruding head rivets with a ring around the manufactured head, caused during the rivet set, can be accepted; if less than 10 percent of the rivets have rings and the depth of cut is less than 25 percent of the driven head height. Rivets with head rings off-set, by more than one eighth of the head diameter, can not be accepted - (Refer to Figure - Detail B).
    Flush head rivets:
    The manufactured head can be dented, during the rivet set, when the rivet set has a spherical radius of not less than 1.000 in. (25.4 mm).
  10. Necessary hole fill:
    NOTE
    This does not apply to rivets that are spun set.
    The procedure used to form the upset heads, of solid rivets, causes the shank to become larger and fill the hole. The voids between the rivet shank and hole must not be more than 40 percent of the surface area of the hole.
    Hand peening of shanks to upset rivet heads - (For rivets made of the materials specified in Figure) is not permitted; because fast cold working of such materials does not let the shank become sufficiently large to fill the hole.
3. 1. General:
    The sheet hole sizes, for all such rivets, is specified in Figure. Cracks in the swaged or flared ends can not be accepted. The rivet end must be swaged to a minimum diameter; equal to the shank diameter, plus 15 percent of that diameter.
  2. Flare angle:
    To make sure the flare bend is not too thin, the flare angle must be approximately the same as the chamfer; into which the flare is set. Unless specified differently, the maximum chamfer angle must be the minimum angle of the approved setting tool - (Refer to Figure - Detail C). The flare angle of hollow rivets, not set to a chamfer, must be approximately 60 degrees - (Refer to Figure - Detail D).
4. 1. Damaged sheets - (For example, sheets with bulged edges) or open seams that let a 0.001 in. (0.02 mm) feeler gage touch the rivet shank, or other unwanted sheet damage - (Refer to Figure - Detail E), can not be accepted.
  2. Bulged sheets, caused when rivet shanks become expanded between the sheets - (Or when chips become caught between the sheets), can not be accepted - (Refer to Figure - Detail F).
  3. Sheet damage caused by rivet set or shaver:
    Cuts or damage to sheets, around the rivet heads, can not be accepted.
  4. Counter surfaces:
    Countersinks which are too large, or not in the center, can not be accepted. Also, cracks in the counter surfaces can not be accepted.
5. 1. Rivets that are loose, after they are set, must be replaced.
  2. A rivet that is the same size as the loose rivet can replace the loose rivet if the hole diameter is not more than the limits given in Figure.
6. 1. Incorrectly driven rivets and larger holes, or counter surfaces, can be corrected with larger rivets; when not more than 10 percent of the rivets are damaged and if the rivets are used to join only metal sheets. All the conditions that follow must then be obeyed:
    The damage is not more than the tolerance for the subsequent rivet installation dimension.
    The rivets are used for sheet metal joints only.
    Ninety percent of the minimum edge distance, and the necessary distance between the rivets, are kept for the larger rivets.
    Sufficient head clearance is available for the larger rivets.
    The sheet thickness is not less than the minimum necessary for the larger rivets.
7. 1. A minimum clearance of 0.002 in. (0.05 mm) must be kept between adjacent sheets, before they are riveted - (Refer to Figure - Detail G).
8. 1. The maximum permitted clearance, between the edge of the upset rivet head and the sheets, is given on Figure - Detail H.
9. 1. Hardness:
    For cold upset heads, a hardness check must be made; in the areas shown on Figure. The hardness value must not be more than Rockwell-C40; or its equivalent.
10. 1. Stem and lock collar flushness:
    For those rivets (other than CherryMAX) where the stem snaps off flush with the manufactured head of the rivet: The stem and locking collar flushness must be within the limits given in Figure. The collar must be flush or below the land of the stem.
    For CherryMAX rivets:
    The locking collar must be flush within plus 0.005 in. (0.127 mm) with the top surface of the rivet head. Stem flushness must be within the limits shown in Figure. Where the locking collar is flush with the top of the rivet head, it can be safely concluded that the stem is within flushness tolerance limits.
    All rivet stem dimensions (including CherryMAX) refer to the top edge of the land adjacent to the break notch. No dimensional reference is made to the uneven break surface.
    For either type of rivet, a slight collar flash caused by the pressures necessary to drive the collar, is acceptable with the limit shown in Figure.
  2. Trim the stems:
    The stem can be milled or trimmed, flush with the head, when the head is open; or when injury to persons, or damage to materials, can be caused by stems that are not trimmed. Refer to Step, step 3.C.(5),(a), for the limits. Rivets that use lock collars, to keep the stems, must not have the heads or collars trimmed or shaved. Stems that are loose, or do not have the necessary axial push-out load given in Figure, must be rejected; the rivet must then be replaced. The installed and locked stem must meet or exceed the push-out limits given in Figure. The stem push-out tool must be 0.007 in. (0.18 mm) smaller than the minimum rivet stem.
11. 1. Clearances:
    With reference to Figure - Detail A, no clearance is permitted between:
    The collar and the pin.
    The collar and the sheet.
    The manufactured head of the pin and the sheet, above the limits given in Step, Step.
  2. Trim material:
    Where the trim material is cut from the collar, at the edge of the pin, a thin sharp fin, not more than 0.010 in. (0.25 mm) thick, can be accepted - (Refer to Figure - Detail B). Also, the trim edge of the collar can be none symmetrical; because of the trim procedure.
  3. Shoulder and/or ring:
    The collar must be in the shape of a smooth cone, symmetrical with the rounded end of the pin. There can be a shoulder at the base of the collar, or a ring up to 0.030 in. (0.76 mm) high at the top of the collar, if all the other instructions are obeyed - (Refer to Figure).
12. 1. Clearances:
    With reference to Figure and Figure, no clearance is permitted between:
    The collar and the sheet.
    The manufactured head of the pin and the sheet, above the limits given in Step.
  2. Swaged collar dimensions:
    Unless specified differently, the swaged collar must have the dimensions given on Figure and Figure.
  3. Rivet pin projection:
    Unless specified differently, the installed stump rivet pin must follow the projection instructions given on Figure. Also, the pull rivet pin must follow the projection instructions given on Figure; before it is trimmed and the end broken-off.
  4. Rivet pin trim:
    The broken end of the rivet pin can be milled, or trimmed, to get a smooth end; but do not touch the swaged collar with the tool.
  5. Angled surface:
    When the collar is swaged on to a slope, or angular surface, dimensions B and C - (Refer to Figure and Figure) must be examined; at 90 degrees to the slope or surface.
1. Make sure that you remove and install protection covers as necessary to prevent damage to the adjacent surfaces, and to make sure that rivet parts and pieces do not go into open areas, cavities, holes, or ports.
2. Carefully remove rivets to prevent damage to the detail parts. See Figure.
3. 1. If there is no center indentation, do one of the subsequent procedures:
    Blind rivet removal tool procedure.
    Use the blind rivet removal tool and the tool manufacturers instructions.
    Center-punch and drill procedure.
    Center-punch the rivet for the start of drilling in the manufactured head. See Figure, View A.
    Use a drill size smaller than the rivet shank diameter. Keep the drill perpendicular to the surface and drill through the head and a small distance into the rivet shank. Do not drill into the rivet base structure. Do not oversize the rivet hole. See Figure, View B.
    Put a protection pad under the rivet to collect the rivet head. Use a punch, the same size as the drill (or smaller), to punch out the upset head. See Figure, View C.
    Remove the rivet heads and all remaining unwanted material.