Rivets are pin-like, permanent mechanical fasteners with a head and tail that create a fixed joint by fastening aluminum panels and structural elements together in aircraft manufacturing and repair. Solid shank rivets, formed from aluminum alloy, are driven with a bucking bar where high strength and shear resistance are needed, while countersunk or convex head styles are selected for smooth aerodynamic surfaces. Blind and self-piercing types extend rivet usage to hard-to-reach or pre-unpierced areas. All riveting operations must comply with specification MS33522 and part numbers like AN470AD to guarantee reliability throughout the airframe.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is a rivet on an aircraft?
A rivet on an aircraft is a structural fastener with a plane unthreaded shaft and a second head is formed after the fastener is in place. It is inserted through predrilled holes to join two or more parts together, filling the hole completely so the heads are flush with the surface of the aircraft. Rivets are pin-like fasteners used to create a fixed and permanent joint, most commonly on the skins of the fuselage and wings, with rivet pitch spacing between rivets. Because the rivet cannot be easily removed once installed, solid rivets are highly safe and reliable fasteners that permanently hold metal plates and multiple layers of material.
What is the purpose of a rivet in a plane?
The rivet's purpose is to hold two components together and create a fixed and permanent joint inside the airframe. On the fuselage and wings the fastener is used to join aluminum alloy, magnesium alloy and steel parts, so the entire load passes from skin to stringer without slipping. Solid rivets prevent waviness in a skin panel, and the universal head that makes little bumps all over the plane was later replaced by the flush type because the dome head caused a lot of drag. The flush rivet was developed to eliminate dome-head drag and assure aerodynamic smoothness. Steel rivets are used to join steel parts, and when bonded joints must be secured against peeling the same principle applies: materials that are to be bonded together get a hole drilled through them, a rivet is inserted, and the joint becomes both glued and riveted. Blind rivets are suited for maintenance tasks where accessibility is limited. An incorrectly installed rivet leads to skin cracking, so each rivet is inspected to confirm it connects the two components from the inside without defect.
What are the types of rivets used in aircraft?
The major types of rivets used in aircraft are solid, blind, tubular and split; high-strength equivalents are the Huck and Hi Shear rivets. Solid-shank rivets, the most traditional form, are used on exterior surfaces and in repair work; they must be driven with a bucking bar. Their heads are universal, round, countersunk, flat or oval, and the shank is high-strength titanium. Universal head rivets combine round, flat and brazier profiles, replacing the pre-war round head (AN430), flat head (AN442) and brazier head (AN455/AN456) styles. Roundhead rivets are retained for interior locations. The 100 countersunk heads give an aerodynamic exterior finish, so countersunk rivets are used extensively on the exterior of aircraft. Aluminum rivets, especially in grade V 65 alloy, are widely used in wing and fuselage structures. Steel rivets serve high-stress areas. MS20470 designates the round universal head, while MS9460 solid rivets offer corrosion-resistant characteristics.
Blind rivets are major types installed where a bucking bar cannot reach; they have been used since the DC-3 programme. Early blind rivets include the Cherry friction-lock rivet and the locked-spindle CherryMAX rivet, the latter carrying a visibly inspectable mechanical locking device and being used in thin-sheet applications where other blind rivets damage the material. Blind rivets are supplied in countersunk versions and are removed by drilling. Pop rivet is a trademarked, non-technical name for some blind rivets. Chobert rivets, a tubular type, were first used on the DC-3. Semi-Tubular rivets have a hole in the field end. Split rivets fall under the metal-piercing category. NAS1097 rivets and oversize rivets with AD solid aluminum shear strength are also employed throughout the aerospace industry.
What is the difference between aircraft rivets and pop rivets?
The difference between aircraft rivets and pop rivets is that aircraft-grade solid rivets demand access to both sides of the workpiece; a rivet gun on one face and a bucking bar on the other squeeze the shank, upsetting it into a permanent shop head. Pop rivets - blind, hollow, tubular rivets - can be installed from only one side. The installer inserts the rivet, squeezes the rivet gun, and the jaws inside the gun grab the mandrel, pulling very hard until the shaft expands and the pin fractures.
Although pop rivets are the next most common option on the market and appear on ships or bridges, they differ from structural aircraft rivets in strength and precision. Cherry rivets, a subset type of blind or pop rivet designed for aviation, use a mandrel of higher precision that leaves a stronger, stiffer joint, yet they are still limited to secondary or non-critical airframe zones. Thus, solid aircraft rivets remain the primary choice for primary structures, while pop-style blind rivets serve where one-sided access and speed outweigh ultimate load-bearing requirements.
How do aircraft rivets work?
To work, the rivet is first pushed through the aligned pilot holes of the sheets; the shank must fill the hole completely so that no relative motion occurs. Solid shank rivets are driven with a bucking bar on one side and a pneumatic percussive gun on the other. The gun hammer strikes the factory head via a set that matches the universal or countersunk shape, while the bucking bar gives the reaction force that upsets the tail. As the tail is compressed it swells inside the hole, work-hardens, and forms the shop head; this volumetric expansion locks the rivet in place and lets the shank transmit shear while the two heads carry tension. Pressure riveting replaces the hammer with a hydraulic system that squeezes the rivet in one smooth stroke, and the result is the same: the rivet expands until it takes all the space available and the panels are clamped by friction and by the formed heads.
Where the structure is reached from one side only, blind rivets are used. Here the mandrel is drawn through the hollow body by a rivet puller; the mandrel deforms the rivet's body, breaks off, and leaves a permanent friction-lock joint. Wet installation further improves durability: sealant is applied before driving which transmits shear and stops moisture, guaranteeing that the rivet, once set, cannot loosen under service loads.
Why do aircraft use rivets?
Aircraft use rivets for structural integrity, fatigue resistance, and manufacturing efficiency. Aircraft rely mainly on two-piece solid rivets wherever an assembler can reach both sides of the sheet, and on one-piece blind rivets wherever the skin-to-structure mating location is not accessible. In either case the joint is made from the inside, giving a stronger, lighter connection than a bolted equivalent. Manufacturers and repair depots both keep the same choice because a correctly installed rivet is made a little smaller than a bolt, saving weight, and because a riveted panel is much easier to remove or replace when inspections or repairs are needed. Rivets stand up to vibration better than normal screws and prevent crack propagation, so they keep the safety level high.
Why do planes use rivets instead of welding?
Planes use rivets instead of welding because thin skins are difficult to weld, and welding generally weakens the parent material. The welding heat produces a heat-affected zone that always decreases strength. Aluminum, the dominant skin material, does not weld: an oxide layer blocks fusion, and the metal is not tolerant to heat, becoming weaker when exposed to it.
Rivets are stronger and more durable than welded joints, and a riveted panel is easier to replace after damage. Riveting is faster, more stable and reliable, yet still forgiving. Rivets are also easy to inspect and repair on the flight line. While laser welding and friction-stir welding appear in modern aircraft manufacturing, they are not welds on the thin skins and rivets remain the proven choice for the exterior of the components.
What are aircraft rivets made of?
Typical aircraft rivets are composed of aluminum alloys, titanium, and nickel based alloys. The material used for the majority of aircraft solid shank rivets is aluminum alloy. 2117 is the most common aluminum alloy used in aircraft rivets. AD rivets are made from a hard aluminum alloy. Soft rivets, made from pure aluminum, are called ‘A’ rivets.
MS20470 solid rivets are crafted from aluminum and titanium alloys. MS20426 rivets are made from aluminum alloys and titanium alloys with a countersunk head. 5056 rivets are made from magnesium alloy that is resistant to corrosion. MS9460 rivets are made from stainless steel. Blind rivets are made from soft aluminum alloy, steel (including stainless steel), copper, and Monel.
High shear pin rivets are made from aluminum, stainless steel, titanium, or carbon steels. Stainless steel rivets are made of low carbon steel containing at least 10.5% chromium by weight. The corrosion resistance of stainless rivets is boosted by increasing the chromium content together with the addition of other elements like nickel, molybdenum, and titanium.
Monel rivets substitute for those made of corrosion resistant steel in some cases. Rivets are used to join nickel steel alloys, titanium parts, and magnesium alloy structures. Stem 2017 aluminum alloy and sleeve 2117 aluminum alloy are material combinations for rivets. Stem 2017 aluminum alloy and sleeve 5056 aluminum alloy are other alternative material combinations for rivets.
What are the specifications for aircraft rivets?
Rivet specifications cover preparation for and installation of buck type rivets. The rivet type, size, and material shall be as specified on the engineering drawing, parts list or specification, and rivet handling shall be performed in accordance with MIL-R-47196A. For example, MS20470AD-5-3C is a 5/32 inch (3.97 mm) diameter, 3/16 inch (4.76 mm) length, certified rivet with a minimum shear strength of 75,000 psi (517.1 MPa). Rivet diameters are commonly measured in 1/32-inch (0.79375 mm) increments and lengths in 1/16-inch (1.5875 mm) increments; the proper diameter rivet is 3 x 0.050 = 0.150 inch (3.81 mm). Replacement rivet diameter is slightly larger than specified size, usually about 0.010 inch (0.254 mm), but repairs with more than two adjacent oversize rivets are prohibited, and combined oversize rivet hole repairs and oversize countersink repairs shall be limited to a maximum of 20 percent of the rivets or 10 rivets in a single rivet pattern, whichever is less.
The head of an aircraft rivet is loaded in shear and bearing. Rivet head shall be flush within 0.010 inch (0.254 mm) above to 0.005 inch (0.127 mm) below the material surface. Aircraft rivet shop heads are formed on the shank side of the rivet using the next smaller size universal type die, and the bucked counter head diameter of the rivet joint must be larger than 1.4 times the diameter of the shank. Rivet assemblies shall be of uniform quality and free from cracks, gaps, sharp edges, burrs, loose parts, or other defects that render the assemblies unsuitable for their intended purpose.
Aircraft rivet standards include NAS, MS, and AN series. NAS 177-14-17 identifies a 100 countersunk head rivet where 14 equals nominal diameter in 32nds of an inch and 17 equals maximum grip length in 16ths of an inch. MS20470AD series Universal Head rivets are solid 2117-T4 aluminum alloy, and the AD designation denotes 2117-T aluminum alloy. Suppliers offer MS20470AD rivets in certified 1 lb (0.45 kg) packs like MS20470AD-5-3C and in uncertified 1/4 lb (0.11 kg) packs like MS20470AD-4-7. Cherry blind rivets cost approximately 30 cents to 1 dollar per rivet and require four different lengths, while standard Avex rivets cost about 8 cents per rivet and will join from grip 0 to grip 1/4 inch (0 to 6.35 mm). High-strength materials like aluminum, titanium, and stainless steel are chosen based on weight, strength, and corrosion resistance; for example, the shank is high-strength (95-ksi shear) titanium and the collar is 2024 aluminum, and the pin and sleeve are coated with a lubricant and a corrosion inhibitor.
What is aircraft rivet nomenclature?
Aircraft rivet nomenclature is the industry language that tells the mechanic every detail about a permanent mechanical fastener without looking at the part. Every solid rivet used in aerospace applications begins with a lettered prefix, and AN and MS designators are identical and interchangeable. AN is Air Force-Navy standard number, MS is Military Standard Specification, and NAS equals National Aircraft Standard. These prefixes mean the part is designed and manufactured to strict standards for aircraft use, while a NAS 1097 or NAS 177 prefix signifies thin-sheet or reduced-head variations.
The numbering order is fixed: head style comes first, then material code, then shank diameter, and finally length. The three-digit number signifies whether the head is flat or domed. AN430 is round head, AN441 is flat head, AN456 is brazier head, AN426 indicates countersunk head, and AN470 is universal head rivet that combines roundhead, flathead, and brazier head geometry. Typical part-number segments like AN470AD3-5 therefore unpack as universal head style, 2117-T aluminum alloy, 3/32 inch (2.38 mm) shank, 5/16 inch (7.94 mm) overall length.
Material identity is carried by a single letter or code placed after the head digits. A indicates 1100-F aluminum and shows no head mark, AD indicates 2117-T4 aluminum alloy identifiable by a dimple head mark, B equals 5056 aluminum marked with a raised cross, 2219-T81 aluminum carries an indented square, 2219-T62 an indented triangle, 7050-T73 an indented ring, 2024-T4 a raised double dash, 2017-T4 a raised dot, 45Cb titanium an indented diamond, while stainless and corrosion-resistant steels use codes C and F and leave no head mark. Monel, brass, copper and Inconel likewise have no head mark or the mark varies. Specialty rivets like Cherry rivet Q style self-plugging types follow the same order but add their own lettered suffix.
Diameter is indicated in 32nds of an inch: for example, 4 indicates 4/32 and 12 indicates 12/32. Length is indicated in 16ths of an inch: for example, 8 indicates 8/16 and 17 indicates 17/16 maximum grip. Rivet length includes the head and tail. A complete part number like NAS 177-14-17 decodes as 100 countersunk head, 14/32 inch diameter (11.11 mm), 17/16 inch maximum grip length (26.99 mm). Assortment kits therefore use the same coded call-outs so that any rivet can be ordered or selected without opening the package, and rows of similar rivets are shown in drawing symbols only at each end to keep aircraft blueprints uncluttered and coherent.
What is the minimum edge distance for an aviation rivet?
For solid driven rivets the industry-standard minimum edge distance is two times the rivet diameter (2D). On many light-aircraft structures, this 2D value is reduced to 1.5D when analyses show adequate bearing strength, but below 2D a large drop in bearing strength occurs and approval must come from the responsible design authority. The maximum permissible edge distance is not fixed; instead it is set by the need to prevent moisture ingress and skin waviness, so designers seldom exceed 4D and usually stay closer to 3D, while still observing the absolute minimums shown on the approved drawing.
What is aviation rivet pitch?
Rivet pitch is defined as the distance between the centers of adjacent rivets in a row, and it is accepted to be 8 to 10 times the rivet diameter. Closely related spacing is transverse pitch, the perpendicular distance between centerlines of two adjacent rows of rivets and this gauge distance is nominally 0.866 rivet pitch, while the diagonal rivet pitch is usually kept at 75 percent of the row pitch. Rivet spacing must not exceed ten rivet shank diameters.
Layout begins with calculating the required pitch and marking centerlines before drilling. Variables of overall layout of rivet joints include the number of rivets, layout patterns (in-line or staggered), number of riveting rows, row spacing, rivet pitch, and distance from the last rivet to the edge of the structure. Skins need a relatively small rivet pitch to prevent waviness, so designers often choose a pitch that provides a smooth aerodynamic and aesthetic finish rather than one dictated purely by strength. Hence, rivet pitch determines spacing between rivets, controls skin waviness, and is the first quantity calculated and laid out when planning any riveted joint.
