question: Why rivets are still used when we now have advanced welding techniques and hex-bolts?
comment: Rivets are very strong in general. Maybe not the cheapo ones they use in a waste disposal but overall. Modern airplanes fuselages are held together (mostly) with rivets. Look at any bridge dating back to the Industrial revolution, if they use steel they’ll be held together with rivets (that have lasted centuries).
passages: Until relatively recently, structural steel connections were either welded or riveted. High-strength bolts have largely replaced structural steel rivets. Indeed, the latest steel construction specifications published by AISC (the 14th Edition) no longer covers their installation. The reason for the change is primarily due to the expense of skilled workers required to install high strength structural steel rivets. Whereas two relatively unskilled workers can install and tighten high strength bolts, it takes a minimum of four highly skilled riveters to install rivets.
   "Riveting" is one of the most ancient metalwork joining processes. Its use declined markedly during the second half of the 20th century, but it still retains important uses in industry and construction, and in artisan crafts such as jewellery, medieval armouring and metal couture in the early 21st century. The earlier use of rivets is being superseded by improvements in welding and component fabrication techniques.
   The last commonly used high strength structural steel rivets were designated ASTM A502 Grade 1 rivets.
  
  Such riveted structures may be insufficient to resist seismic loading from earthquakes if the structure was not engineered for such forces, a common problem of older steel bridges. This is because a hot rivet cannot be properly heat treated to add strength and hardness. In the seismic retrofit of such structures it is common practice to remove critical rivets with an oxygen torch, precision ream the hole, then insert a machined and heat treated bolt.
  
  Section::::Types.:Semi-tubular rivets.
   Section::::Installation.
  
  Section::::Installation.:Solid and semi tubular rivets.
  
  There are several methods for installing solid rivets.
  
  BULLET::::- Manual with hammer and handset or bucking bar
  
  BULLET::::- Pneumatic hammers
  
  BULLET::::- Handheld squeezers
  
  BULLET::::- Riveting machines
  
  BULLET::::- Pin hammer, rivet set
   Before welding techniques and bolted joints were developed, metal framed buildings and structures such as the Eiffel Tower, Shukhov Tower and the Sydney Harbour Bridge were generally held together by riveting, as were automobile chassis. Riveting is still widely used in applications where light weight and high strength are critical, such as in an aircraft. Many sheet-metal alloys are preferably not welded as deformation and modification of material properties can occur.
   The typical assembly process requires the operator to install the rivet in the nose of the tool by hand and then actuate the tool. However, in recent years automated riveting systems have become popular in an effort to reduce assembly costs and repetitive disorders. The cost of such tools range from US$1,500 for autofeed pneumatics to US$50,000 for fully robotic systems.
   Internally and externally locked structural blind rivets can be used in aircraft applications because, unlike other types of blind rivets, the locked mandrels cannot fall out and are watertight. Since the mandrel is locked into place, they have the same or greater load-carrying capacity as solid rivets and may be used to replace solid rivets on all but the most critical stressed aircraft structures.
   Because there is effectively a head on each end of an installed rivet, it can support tension loads. However, it is much more capable of supporting shear loads (loads perpendicular to the axis of the shaft).
  
  Fastenings used in traditional wooden boat building, such as copper nails and clinch bolts, work on the same principle as the rivet but were in use long before the term "rivet" was introduced and, where they are remembered, are usually classified among nails and bolts respectively.
  
  Section::::Types.
  
  There are a number of types of rivets, designed to meet different cost, accessibility, and strength requirements:
   BULLET::::- Soldering
  
  BULLET::::- Welding
  
  Section::::See also.
  
  BULLET::::- Boiler
  
  BULLET::::- Cleco
  
  BULLET::::- Clinker (boat building)
  
  BULLET::::- Ring binder
  
  BULLET::::- Rivet nut
  
  BULLET::::- Rosie the Riveter
  
  Section::::External links.
  
  BULLET::::- "Popular Science", November 1941, "Self-Setting Explosive Rivet Speeds Warplane Building" system used by both the US and Germany in World War Two for aircraft assembly – see bottom half of page
  
  BULLET::::- "Four Methods of Flush Riveting", film made by Disney Studios during World War Two
  
  BULLET::::- "Hold Everything", February 1946, "Popular Science" new rivet types developed during World War Two
   Rivets may also be upset by hand, using a ball-peen hammer. The head is placed in a special hole made to accommodate it, known as a rivet-set. The hammer is applied to the buck-tail of the rivet, rolling an edge so that it is flush against the material.
  
  Section::::Testing.
  
  Section::::Testing.:Solid rivets for construction.
   A version of the Oscar rivet is the Olympic rivet which uses an aluminum mandrel that is drawn into the rivet head. After installation, the head and mandrel are shaved off flush resulting in an appearance closely resembling a brazier head driven rivet. They are used in repair of Airstream trailers to replicate the look of the original rivets.
  
  Section::::Types.:Drive rivet.
   While structural blind rivets using a locked mandrel are common, there are also aircraft applications using "non-structural" blind rivets where the reduced, but still predictable, strength of the rivet without the mandrel is used as the design strength. A method popularized by Chris Heintz of Zenith Aircraft uses a common flat-head (countersunk) rivet which is drawn into a specially machined nosepiece that forms it into a round head rivet, taking up much of the variation inherent in hole size found in amateur aircraft construction. Aircraft designed with these rivets use rivet strength figures measured with the mandrel removed.
  
  Section::::Types.:Oscar rivets.
   Blind rivets are used almost universally in the construction of plywood road cases.
  
  Common but more exotic uses of rivets are to reinforce jeans and to produce the distinctive sound of a sizzle cymbal.
  
  Section::::Joint analysis.
   Section::::Types.:Blind rivets.
   Blind rivets, commonly referred to as "pop" rivets (POP is the brand name of the original manufacturer, now owned by Stanley Engineered Fastening, a division of Stanley Black & Decker) are tubular and are supplied with a mandrel through the center. The rivet assembly is inserted into a hole drilled through the parts to be joined and a specially designed tool is used to draw the mandrel into the rivet. This expands the blind end of the rivet and then the mandrel snaps off. These types of blind rivets have non-locking mandrels and are sometimes avoided for critical structural joints because the mandrels may fall out, due to vibration or other reasons, leaving a hollow rivet that has a lower load-carrying capability than solid rivets. Furthermore, because of the mandrel they are more prone to failure from corrosion and vibration. Unlike solid rivets, blind rivets can be inserted and fully installed in a joint from only one side of a part or structure, "blind" to the opposite side.
   BULLET::::- The flush rivet displaced the domed rivet in the 1930s and pneumatic rivet guns work in combination with a heavy reaction bucking bar; not depending on plastic deformation, specialist rivets were developed to improve fatigue life as shear fasteners like the Hi-Lok, threaded pins tightened until a collar breaks off with enough torque.
   Solid rivets are one of the oldest and most reliable types of fasteners, having been found in archaeological findings dating back to the Bronze Age. Solid rivets consist simply of a shaft and head that are deformed with a hammer or rivet gun. A rivet compression or crimping tool can also deform this type of rivet. This tool is mainly used on rivets close to the edge of the fastened material, since the tool is limited by the depth of its frame. A rivet compression tool does not require two people, and is generally the most foolproof way to install solid rivets.
   Rivets need to be harder than the materials being joined . they are heat treated to various levels of hardness depending on the material's ductility and hardness. Rivets come in a range of diameters and lengths depending on the materials being joined; head styles are either flush countersunk or pan heads.
  
  Depending on the rivet setter configuration, i.e. hydraulic, servo, stroke, nose-to-die gap, feed system etc., cycle times can be as quick as one second. Rivets are typically fed to the rivet setter nose from tape and come in cassette or spool form for continuous production.
   Modern trivets are made from metal, wood, ceramic, fabric, silicone or cork.
   Friction stir welding, a new type of welding, was discovered in 1991 by The Welding Institute (TWI). The innovative steady state (non-fusion) welding technique joins materials previously un-weldable, including several aluminum alloys. It plays an important role in the future construction of airplanes, potentially replacing rivets. Current uses of this technology to date include welding the seams of the aluminum main Space Shuttle external tank, Orion Crew Vehicle test article, Boeing Delta II and Delta IV Expendable Launch Vehicles and the SpaceX Falcon 1 rocket, armor plating for amphibious assault ships, and welding the wings and fuselage panels of the new Eclipse 500 aircraft from Eclipse Aviation among an increasingly growing pool of uses.
   The first rivet nut was created by BF Goodrich in the 1930s, and sold under the trademark RIVNUT®. It was first used to mount rubber de-icing boots to aircraft wings.
  
  Section::::Usage.
   A pop rivet gun is made to apply pop rivets to a workpiece. This type of rivet gun is unique in its operation, because it does not hammer the rivet into place. Rather, a pop rivet gun will form a rivet in-place.
   Self-pierce riveting (SPR) is a process of joining two or more materials using an engineered rivet . Unlike solid, blind and semi-tubular rivets, self-pierce rivets do not require a drilled or punched hole.
   A rivet is essentially a two-headed and unthreaded bolt which holds two other pieces of metal together. Holes are drilled or punched through the two pieces of metal to be joined. The holes being aligned, a rivet is passed through the holes and permanent heads are formed onto the ends of the rivet utilizing hammers and forming dies (by either coldworking or hotworking).
  
  Rivets are commonly purchased with one head already formed.
   The stress and shear in a rivet is analyzed like a bolted joint. However, it is not wise to combine rivets with bolts and screws in the same joint. Rivets fill the hole where they are installed to establish a very tight fit (often called interference fit). It is difficult or impossible to obtain such a tight fit with other fasteners. The result is that rivets in the same joint with loose fasteners carry more of the load—they are effectively more stiff. The rivet can then fail before it can redistribute load to the other loose fit fasteners like bolts and screws. This often causes catastrophic failure of the joint when the fasteners "unzip". In general, a joint composed of similar fasteners is the most efficient because all fasteners reach capacity simultaneously.
  
presuppositions: If more advanced welding techniques and hex bolts are available, those should be used instead of rivets.
corrections: Rivets are very strong and have been proven to 
raw_presuppositions: If more advanced welding techniques and hex bolts are available, those should be used instead of rivets. Rivets don't have a use now that we have more advanced welding techniques and hex-bolts.
raw_corrections: Rivets are very strong and have been proven to  Rivets still have a use even though we have more advanced welding techniques and hex-bolts, because they are so strong.