Fastener

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Typical fasteners (US quarter shown for scale) Screws.jpg
Typical fasteners (US quarter shown for scale)

A fastener (US English) or fastening (UK English) [1] is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or dismantled without damaging the joining components. [2] Steel fasteners are usually made of stainless steel, carbon steel, or alloy steel.

Contents

Other methods of joining materials, some of which may create permanent joints, include: crimping, welding, soldering, brazing, taping, gluing, cement, or the use of other adhesives. Force may also be used, such as with magnets, vacuum (like suction cups), or even friction (like sticky pads). Some types of woodworking joints make use of separate internal reinforcements, such as dowels or biscuits, which in a sense can be considered fasteners within the scope of the joint system, although on their own they are not general-purpose fasteners.

Furniture supplied in flat-pack form often uses cam dowels locked by cam locks, also known as conformat fasteners. Fasteners can also be used to close a container such as a bag, a box, or an envelope; or they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container, etc. There are also special-purpose closing devices, e.g., a bread clip.

Items like a rope, string, wire, cable, chain, or plastic wrap may be used to mechanically join objects; but are not generally categorized as fasteners because they have additional common uses. Likewise, hinges and springs may join objects together, but are ordinarily not considered fasteners because their primary purpose is to allow articulation rather than rigid affixment.

Industry

In 2005, it was estimated that the United States fastener industry runs 350 manufacturing plants and employs 40,000 workers. The industry is strongly tied to the production of automobiles, aircraft, appliances, agricultural machinery, commercial construction, and infrastructure. More than 200 billion fasteners are used per year in the U.S., 26 billion of these by the automotive industry. The largest distributor of fasteners in North America is the Fastenal Company. [3]

Materials

There are three major steel fasteners used in industries: stainless steel, carbon steel, and alloy steel. The major grade used in stainless steel fasteners: 200 series, 300 series, and 400 series. Titanium, aluminium, and various alloys are also common materials of construction for metal fasteners. In many cases, special coatings or plating may be applied to metal fasteners to improve their performance characteristics by, for example, enhancing corrosion resistance. Common coatings/platings include zinc, chrome, and hot-dip galvanizing. [4] [5]

Applications

When selecting a fastener for industrial applications, it is important to consider a variety of factors. The threading, the applied load on the fastener, the stiffness of the fastener, and the number of fasteners needed should all be taken into account.

When choosing a fastener for a given application, it is important to know the specifics of that application to help select the proper material for the intended use. Factors that should be considered include:

Types

Structural bolt DIN 6914 with DIN 6916 washer and UNI 5587 nut DIN6914 UNI5587.jpg
Structural bolt DIN 6914 with DIN 6916 washer and UNI 5587 nut

A threaded fastener has internal or external screw threads. [7] The most common types are the screw, nut and bolt, possibly involving washers.

Other more specialized types of threaded fasteners include captive threaded fasteners, stud, threaded inserts, and threaded rods.

Other types of fastener include:

Common fastener head styles

Source: [8]

Standards & traceability

There are multiple standards bodies for fasteners, including the US Industrial Fasteners Institute and the European Industrial Fastener Institute.

ASME B18 standards on certain fasteners

The American Society of Mechanical Engineers (ASME) publishes several standards on fasteners. Some are:

For military hardware

American screws, bolts, and nuts were historically not fully interchangeable with their British counterparts, and therefore would not fit British equipment properly. This, in part, helped lead to the development of numerous United States Military Standards and specifications for the manufacturing of essentially any piece of equipment that is used for military or defense purposes, including fasteners. World War II was a significant factor in this change.

A key component of most military standards is traceability. Put simply, hardware manufacturers must be able to trace their materials to their source, and provide traceability for their parts going into the supply chain, usually via bar codes or similar methods. This traceability is intended to help ensure that the right parts are used and that quality standards are met in each step of the manufacturing process; additionally, substandard parts can traced back to their source. [9]

History

In 1988, the United States House Energy Subcommittee on Oversight and Investigations investigated counterfeit, mismarked, substandard fasteners and found extensive use in critical civilian and military infrastructure. [10] [11] [12] As a result, they proposed Fastener Quality Assurance Act of 1988 (HR5051) that would require laboratory testing of fasteners in critical use applications prior to sale. [10]

See also

Related Research Articles

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Torx is a trademark for a type of screw drive characterized by a 6-point star-shaped pattern, developed in 1967 by Camcar Textron. A popular generic name for the drive is star, as in star screwdriver or star bits. The official generic name, standardized by the International Organization for Standardization as ISO 10664, is hexalobular internal. This is sometimes abbreviated in databases and catalogs as 6lobe. Torx Plus,Torx Paralobe and Torx ttap are improved head profiles.

<span class="mw-page-title-main">Rivet</span> Permanent mechanical fastener

A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the tail. On installation, the deformed end is called the shop head or buck-tail.

<span class="mw-page-title-main">Washer (hardware)</span> Thin plate with a hole, normally used to distribute the load of a threaded fastener

A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a bolt or nut. Other uses are as a spacer, spring, wear pad, preload indicating device, locking device, and to reduce vibration.

<span class="mw-page-title-main">Bolted joint</span> Mechanical joint secured by a threaded fastener

A bolted joint is one of the most common elements in construction and machine design. It consists of a male threaded fastener that captures and joins other parts, secured with a matching female screw thread. There are two main types of bolted joint designs: tension joints and shear joints.

<span class="mw-page-title-main">Set screw</span> Type of screw

In American English, a set screw is a screw that is used to secure an object, by pressure and/or friction, within or against another object, such as fixing a pulley or gear to a shaft. A set screw is normally used without a nut, being screwed instead in a threaded hole drilled in only one of the two objects to be secured. A set screw is often headless and threaded along its entire length, so that it will sit entirely inside that hole; in which case it may be called a grub screw or blind screw.

<span class="mw-page-title-main">Sex bolt</span> Type of mating fastener

A sex bolt is a type of fastener comprising a mated pair of screw and post, which are a machine screw and a nut that is barrel-shaped. The nut has a flange and a protruding boss that is internally threaded. The bolt sits within the components being fastened, and the flange provides the bearing surface.

<span class="mw-page-title-main">Computer case screws</span> Hardware used to secure parts of a PC to the case

Computer case screws are the hardware used to secure parts of a PC to the case. Although there are numerous manufacturers of computer cases, they have generally used three thread sizes. The Unified Thread Standard (UTS) originates from the United States, while the ISO metric screw thread is standardized worldwide. In turn, these thread standards define preferred size combinations that are based on generic units—some on the inch and others on the millimetre.

<span class="mw-page-title-main">Flange nut</span>

A flange nut is a nut that has a wide flange at one end that acts as an integrated washer. This serves to distribute the pressure of the nut over the part being secured, reducing the chance of damage to the part and making it less likely to loosen as a result of an uneven fastening surface. These nuts are mostly hexagonal in shape and are made up of hardened steel and often coated with zinc.

<span class="mw-page-title-main">Barrel nut</span>

A barrel nut is a specialized forged nut, and is commonly used in aerospace and ready-to-assemble furniture applications.

<span class="mw-page-title-main">Screw</span> Type of fastener characterized by a thread wrapped around a cylinder core

A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the head. The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread.

<span class="mw-page-title-main">Nut (hardware)</span> Type of fastener with a threaded hole

A nut is a type of fastener with a threaded hole. Nuts are almost always used in conjunction with a mating bolt to fasten multiple parts together. The two partners are kept together by a combination of their threads' friction, a slight stretching of the bolt, and compression of the parts to be held together.

<span class="mw-page-title-main">Rail fastening system</span> Rail-tie/sleeper binding mechanism

A rail fastening system is a means of fixing rails to railroad ties or sleepers. The terms rail anchors, tie plates, chairs and track fasteners are used to refer to parts or all of a rail fastening system. The components of a rail fastening system may also be known collectively as other track material, or OTM for short. Various types of fastening have been used over the years.

<span class="mw-page-title-main">Spring pin</span> Mechanical fastener that secures the position of two or more parts relative to each other

A spring pin is a mechanical fastener that secures the position of two or more parts of a machine relative to each other. Spring pins have a body diameter which is larger than the diameter of the hole they are intended for, and a chamfer on either one or both ends to facilitate starting the pin into the hole. The spring action of the pin allows it to compress as it assumes the diameter of the hole. The force exerted by the pin against the hole wall retains it in the hole, therefore a spring pin is considered a self retaining fastener.

ASTM A325 is an ASTM International standard for heavy hex structural bolts, titled Standard Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength. It defines mechanical properties for bolts that range from 12 to 1+12 inches in diameter.

ASTM F568M is an ASTM International standard for metric bolts, screws and studs that are used in general engineering applications. It is titled: Standard Specification for Carbon and Alloy Steel Externally Threaded Metric Fasteners. It defines mechanical properties for fasteners that range from M1.6 to 100 in diameter. The standard was withdrawn in 2012. and has been replaced by ISO 898-1

<span class="mw-page-title-main">Threaded rod</span> Rod with ridges wrapped around it

A threaded rod, also known as a stud, is a relatively long rod that is threaded on both ends; the thread may extend along the complete length of the rod. They are designed to be used in tension. Threaded rod in bar stock form is often called all-thread (ATR); other names include fully-threaded rod, redi-rod, continuously-threaded rod, and TFL rod.

<span class="mw-page-title-main">Bolt (fastener)</span> Threaded fastener with an external male thread requiring a matching female thread

A bolt is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to a matching nut. The bolt has an external male thread requiring a matching nut with a pre-formed female thread.

<span class="mw-page-title-main">Wrench size</span>

Width across flats is the distance between two parallel surfaces on the head of a screw or bolt, or a nut, mostly for torque transmission by positive locking.

<span class="mw-page-title-main">Furniture screws</span> Screws used on furniture, including specialty screws used on ready-to-assemble furniture

A furniture screw can refer to any type of screw used on furniture. Different types of screws have different uses in furniture.

References

  1. "FASTENING | meaning in the Cambridge English Dictionary". dictionary.cambridge.org.
  2. Stonecypher, Lamar (21 May 2009). "Fasteners - Their Needs and Types". Bright Hub Engineering.
  3. The North American fastener industry - The industry today, archived from the original on 2008-06-13, retrieved 2009-02-08.
  4. "Materials & Coatings". Fastener Solutions. Archived from the original on 2017-08-16. Retrieved 2017-01-16.
  5. "Best Screwdriver Set". Prot Guide. Retrieved 19 October 2023.
  6. "Material Finishes". AALL American Fasteners.
  7. Groover, Mikell P. (2010), Fundamentals of Modern Manufacturing: Materials, Processes, and Systems (4th ed.), John Wiley and Sons, p. 767, ISBN   978-0-470-46700-8.
  8. "Exploring the World of Fastener Head Styles". DMS Fasteners. 2023-04-27. Retrieved 2024-02-19.
  9. "Why Traceability Matters". B & B Electro-Mechanical. Archived from the original on 2019-04-14. Retrieved 2017-01-16.
  10. 1 2 Tribune, Chicago (31 July 1988). "HOUSE REPORT DETAILS DANGERS OF SUBSTANDARD BOLTS". Chicago Tribune. Retrieved 3 March 2024.
  11. United States Congress House Committee on Energy and Commerce Subcommittee on Oversight and Investigations (1988). The Threat from Substandard Fasteners: Is America Losing Its Grip? : a Report of the Subcommittee on Oversight and Investigations of the Committee on Energy and Commerce, U.S. House of Representatives. U.S. Government Printing Office. Retrieved 3 March 2024.
  12. United States Congress House Committee on Energy and Commerce Subcommittee on Oversight and Investigations (1988). Counterfeit Metal Fasteners: Hearings Before the Subcommittee on Oversight and Investigations of the Committee on Energy and Commerce, House of Representatives, One Hundredth Congress, First [and Second] Sessions. U.S. Government Printing Office. p. 319.

Further reading