| Aircraft rivets | | | | determining minimum edge distance and rivet spacing. |
| The two major types of rivets used in aircraft are | | | | Special fasteners may require an FAA field approval. |
| the common solid shank rivets, which must be driven | | | | Blind rivets are used under certain conditions when |
| using an air-driven gun and bucking bar; and special | | | | there is access to only one side of the structure. |
| (blind) rivets, which are installed with special installation | | | | Typically, the locking characteristics of a blind rivet |
| tools. Solid shank rivets are used widely during | | | | are not as good as a driven rivet. Therefore, blind |
| assembly and repair work. They are identified by the | | | | rivets are usually not used when driven rivets can be |
| material of which they are made, the head type, size | | | | installed. |
| of shank, and temper condition. | | | | The 2117 rivets may be driven in the condition |
| The material used for the majority of solid shank | | | | received, but 2017 rivets above 3/16 inch in diameter |
| rivets is aluminum alloy. The strength and temper | | | | and all 2024 rivets are to be kept packed in dry ice |
| conditions of aluminum alloy rivets are identified by | | | | or refrigerated in the "quenched" condition until |
| digits and letters similar to those used to identify | | | | driven, or be re heat treated just prior to driving, as |
| sheet stock. The 1100, 2017-T, 2024-T, 2117-T, and | | | | they would otherwise be too hard for satisfactory |
| 5056 rivets are the six grades usually available. | | | | riveting. |
| AN-type aircraft solid rivets can be identified by code | | | | Aerospace fasteners, special fasteners and blind |
| markings on the rivet heads. A rivet made of 1100 | | | | fasteners. |
| material is designated as an "A" rivet, and has no | | | | When solid shank rivets are impractical to use, then |
| head marking. The 2017-T alloy rivet is designated as | | | | special fasteners are used. Special fastening systems |
| a "D" rivet and has a raised teat on the head. Two | | | | used for aircraft construction and repair are divided |
| dashes on a head indicate a 2024-T alloy designated | | | | into two types, special and blind fasteners. Special |
| as a "DD" rivet. The 2117-T rivet is designated as an | | | | fasteners are sometimes designed for a specific |
| "AD" rivet, and has a dimple on the head. | | | | purpose in an aircraft structure. The name "special |
| A "B" designation is given to a rivet of 5056 material | | | | fasteners" refers to its job requirement and the |
| and is marked with a raised cross on the head. Each | | | | tooling needed for installation. They are used in |
| type of rivet is identified by a part number to allow | | | | fluid-tight areas, on aircraft in air intake areas where |
| the user to select the correct rivet. The numbers are | | | | rivet parts may be ingested by the engine, on |
| in series and each series represents a particular type | | | | aircraft control surfaces, hinges, hinge brack ets, flight |
| of head. | | | | control actuating systems, wing attachment fittings, |
| Countersunk head rivets are used where a smooth | | | | landing gear fittings, on floats or amphibian hulls below |
| finish is desired. The 100-degree countersunk head | | | | the water level, or other heavily-stressed locations on |
| has been adopted as the standard in the United | | | | the aircraft. For metal repairs to the airframe, the use |
| States. The universal head rivet (AN470) has been | | | | of blind rivets must be specifically authorized by the |
| adopted as the standard for protruding-head rivets, | | | | airframe manufacturer or approved by a |
| and may be used as a replacement for the | | | | representative of the FAA. |
| roundhead, flathead, and brazier head rivet. These | | | | Self plugging friction-lock cherry rivets. This patented |
| rivets can also be purchased in half sizes by | | | | rivet may be installed when there is access to only |
| designating a "0.5" after the main length. | | | | one side of the structure. The blind head is formed |
| Replace rivets with those of the same size and | | | | by pulling the tapered stem into the hollow shank. |
| strength whenever possible. If the rivet hole | | | | This swells the shank and clamps the skins tightly |
| becomes enlarged, deformed, or otherwise damaged; | | | | together. When the shank is fully upset, the stem |
| drill or ream the hole for the next larger size rivet. | | | | pulls in two. The stem does not fracture flush with |
| Rivets may not be replaced by a type having lower | | | | the head and must be trimmed and filed flush for the |
| strength properties, unless the lower strength is | | | | installation to be complete. Because of the |
| adequately compensated by an increase in size or a | | | | friction-locking stem, these rivets are very sensitive |
| greater number of rivets. It is acceptable to replace | | | | to vibrations. Inspection is visual, with a loose rivet |
| 2017 rivets of 3/16 inch diameter or less, and 2024 | | | | standing out in the standard "smoking rivet" pattern. |
| rivets of 5/32 inch diameter or less with 2117 rivets | | | | Removal consists of punching out the friction locked |
| for general repairs, pro vided the replacement rivets | | | | stem and then treating it like any other rivet. |
| are 1/32 inch greater in diameter than the rivets they | | | | Mechanical-lock rivets have a device on the puller or |
| replace. | | | | head which locks the centre stem into place when |
| Rivet edge distance is defined as the distance from | | | | installed. Many friction-lock rivet centre stems fall out |
| the centre of the hole to the nearest edge of the | | | | due to vibrations; this in turn, greatly reduces its |
| sheet. Rivet spacing is the distance from the centre | | | | shear strength. The mechanical-lock rivet was |
| of the rivet hole to the centre of the adjacent hole. | | | | developed to prevent that problem. Various |
| Unless structural deficiencies are suspected, the | | | | manufacturers make mechanical-lock fasteners such |
| spacing and edge distance should duplicate those of | | | | as: Bulbed Cherrylock, CherryMax, Olympic-Loks, and |
| the original aircraft structure. If structural deficiencies | | | | Huck-Loks. |
| are suspected, the following may be used in | | | | |