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Fastenright’s Fastener Terminology Glossary

On this page you will find our fastener terminology glossary, full of terms or names that you may not be certain about.

The fastener industry is a complex one, with a wide range of fixings, technical descrptions and finishes all contributing to names that not everyone will be aware of. 

If you’d like to learn more about them, we hope that this glossary will help. It might even point you in the right direction for a product that could prove to be a vital part of an application.

Please click the ‘plus’ symbols to expand each section, and you can close the tabs with the ‘minus’ symbol.


Allen Wrench

Commonly referred to as a hex key or an allen key, this tool is used to drive bolts and screws that have a hexagonally shaped socket.


Allthread is one of the numerous names for threaded rod. It is not a different product, just a different way of referring to the likes of ‘threaded rod’ or ‘threaded bar’. They can be found in building, plumbing and general maintenance applications.


All-metal often refers to locknuts which have no plastic inserts. These nuts are effective under harsh temperatures and extreme corrosive elements. 


Aluminium is an aesthetically pleasing material that is often picked for fasteners or fixings that are required to be both useful – via high corrosion resistance and a lack of ferrousness – and aesthetically sharp.


Black Japanned

A black lacquer which is applied to steel and then baked to provide a smooth, glossy finish. 


Bolts are externally threaded fasteners designed for insertion through holes. They are normally intended to be tightened or released by torquing a nut. 


Brass is an alloy, made using copper and zinc.

Button Head

Button head is a head style for a screw or bolt that generally holds a cylindrical head and a hexagonal drive. Most commonly, they require an allen key or a hex key to be installed or removed.



Captive Screw

A captive screw is a specialist product that cannot be wholly removed from a hole once installed. They are available in a range of head variants, but the key similarity surrounding each product is that they all host a reduced thread. 

Chemical Black

Chemical Black is an oxide coating which is used on non-stainless steel parts, made by forming a reaction between the surface of the material and the salts in the solution.


Chrome is a type of coating that provides corrosion resistance and aesthetically pleasing (or decorative).

Cleveloc (Nut)

Cleveloc refers to self-locking nut with a geometrically developed elliptical collar to provide flexible locking.


Countersunk refers to a head style that is reduced to a flat or bevelled state so that the screw or bolt can be placed in housing flush to the surrounding material.



DIN (Standard, Number)

A DIN number refers to a specific international or European standard that a product (screw, bolt, nut) has been created to, ensuring that there is continuity within the industry surrounding that specific product.


The drive is the system used to turn (and therefore install or uninstall) a screw, and is sometimes the key providing adequate security when the screw is made for that application.

Duplex (and Super Duplex)

Duplex, and subsequently Super Duplex, are alloys used within the fastener industry for their high corrosion resistance and high strength. The alloy provides a number of advantages in fasteners.


E Drive (E5, E6)

An E Drive is a specific drive for a tamper-resistant security screw. The drive is a unique external non-slip head and features five (E5) or six (E6) slots.

Electro Brass Plated

A finish often directly used to finish polished iron or as an intermediate layer for future nickel plating. It can also be used with steel to facilitate rubber adhesion. 






Ferralium is a type of Super Duplex Stainless Steel which is optimised for use within fasteners.


Fibreglass is used in studs and nuts for applications when the fastener should be non-corrosive, low in conductivity, or transparent to electromagnetic waves.

Fine Pitch

Fine pitch threads are often used within the automotive industry. They are more easily tapped into harder materials and have less tendency to loosen.


Flange refers to a head style for bolts where there is a circular ‘flange’ under the head that acts like a washer to distribute a load. A flange is a projected flat rim or collar.






Geomet is a coating and Geomet 500 was specifically developed for fasteners. It is an aesthetically pleasing aqueous based finish.

Green Chromate

Green Chromate is a finish that is generally used on steel, aluminium and zinc. It decreases corrosion rate and can be used as a decorative finish.





Hastelloy is an alloy created with nickel and molydenum. It is available in a number of different grades that are all highly resistant to corrosion.

Hex (Pin)

A hex (or hexagon) drive is similar to a standard socket head screw, with the addition of a security pin within the hexagonal socket recess. The recess resists standard socket bits and allen keys.

High Tensile

High Tensile generally refers to a range of steels beteen grade 8.8 and grade 12.9 – with 8.8 often considered the structural grade for bolts. It is the most common form of high tensile material. 


Hsfg stands for High Strength Friction Grip, and is the name of a type of crack-proof washer. They can be found in the automobile, chemical and power plant industries.







Incoloy is a superalloy that is available in a number of grades. The grades contain different amounts of different materials, such as aluminium, or chromium.


Inconel is a superalloy that is available in a number of grades. The grades contain different amounts of different materials such as cobalt, molybdenum or nickel.

Indented (Foundation Bolt)

Indented Foundation Bolts are a great solution to attach objects or structures to concrete, or for the repairing of foundations.

Insert Nut

There are a wide range of insert nuts which are used to assemble wood and wood based materials using a strong, permanent thread.

Inserts for Plastic

Inserts for Plastic are designed for fast installation into thermoplastics. Inserts for Plastic are available in a wide range hosting various knurl styles.


A system of measurement used in several English-speaking countries and former British colonies.






J Bolt

J Bolts are fasteners shaped like the letter J. The are threaded on their flat side and often used in structural applications like securing walls to concrete foundations.



Kitting is the process of creating a pack or fixing kit, which is ideal for the furniture trade or industries where screws are supplied to enable product assembly by the consumer.

Knurl (Knurled, Knurling)

A knurl is a projected ridge or knob on a fastener, usually around the head or shaft in a pattern of straight, angled, crossed or shaped lines. Knurls are used to help with gripping.



Left-Hand Thread

A Left-Hand thread runs anti-clockwise. Left-Hand threads are not for left handed people as some would assume. They are often used to be reverse threaded, or to create a deliberate incompatibility as a safety indicator.

Low Profile

Refers to a screw that is designed for a reduced head height for aesthetic and space conservation purposes. 


M Number (M2, M4)

The M stands for Metric unit, and when followed by the number refers to the gauge size of a fastener. 

Micro Fastener

A Micro Fastener hosts a small diameter and are generally much smaller for use in things lke electronics, often streamlining the production process as they minimise the need for additional hardware.

Mild Steel

Mild Steel is a mass produced steel that is used across a wide range of fasteners and fixings. It hosts no more than 2% carbon and no other appreciable alloying element.

Metric Thread

Metric Thread is the most widely used thread in the modern day and is available in fine and coarse types.


Molybdenum is a silvery-white metal that when used in fasteners is able to maintain strength at elevated temperatures. Often found in high-temperature vacuum furnaces, glass production and military applications.

Mushroom Head

A Mushroom Head fastener has a large head diameter and a decorative, low profile finish. 






Nickel is an electroplated finish that is often used to provide corrosion or wear resistance to a metal fastener.


A Nut is a fastener that is generally used in conjunction with a bolt to fasten multiple parts together. They host a threaded hole.

Nyloc (Nut)

A Nyloc Nut is often known as a nylon insert locknut, elastic stop nut or polymer insert locknut. It is a locknut with a nylon collar insert that resists turning. 


Nylon is a popular plastic for use in fasteners and fixings due to its high-tensile strength and high wear resistance. Suited for electronic applications.


Oval Pan

Oval Pan is a screw head type that can often be mistaken for a circular shape. The oval shaped head enables it only to be fastened and removed with its matching tool.

Oversized Nut

An Oversized Nut is a large diameter nut available in a range of styles, grades and finishes.



Phillips Head

The Phillips Head is a screw drive style designed to provide a better contact with the screwdriver than the original flat head.


Polyoxymethylene, otherwise known as Delrin or Acetal, is a thermoplastic that is used in fasteners that are required to be durable for use in automotive components and mechanical or electrical engineering.

Powder Coating

Powder Coating is a popular colouring process for fasteners of a number of materials, allowing for a pleasing aesthetic. The process involves finely milled pigment and resin that are sprayed onto the fastener using an electrostatic spray.

Pozi Drive

A screw drive style invented to improve the torque and cam-out of the Phillips head. A second cross added to the first cross to give improved contact of the driver to the screw. 




Quadwing refers to a specific style of screw drive designed to be easier to use and offer significantly higher performance than ordinary cross recess screws.


Rivet Gun

A Rivet Gun is a tool used to install and extract rivets – they are available as manual and pnuematic options. 

Rivet Nut

Rivet Nuts are reliable fasteners for use in thin walled materials, creating a strong thread for high strength fastening from bolts and other threaded articles.

Roll Pin

Roll Pins are fasteners used to secure the position of multiple parts of a machine when they relate to each other. They are often used to fasten flat faces of mating parts together.



Security Fasteners

Security Fasteners, including bolts, nuts and screws are tamper-proof or tamper-resistant fixings that protect applications such as prisons, hospitals, military and automotive.

Sex Bolts

Sex Bolts are mating fasteners provided in a set, consisting of a female barrel nut and a mating male tamper proof screw. They are used in applications requiring moderate to high security.


Sherardising is a form of zinc coating which results in hard wearing and corrosion resistant finish. 

Socket Screw

Socket Screws refer to a screw that is fastened using a hexagonal key. 

Stainless Steel

Stainless Steel is available in a wide range of grades. The two most popular are A2 and A4 stainless steel, which are used a lot within the fastener industry.

Stayblack Finish

Stayblack is a process used on stainless steel to create a matt black coating and is mainly used in the automotive and aerospace industries. It can maintain its appearance under temperatures up to 500 degrees celcius.


Tamper Proof

Tamper Proof fasteners are anti-theft and anti-vandalism fasteners which are designed to be difficult to remove. 


Tantalum is a material used in fasteners and known for its unmatched corrosion resistance in the industry – hosting a similar resistance to glass but the mechanical properties of metal. 

Thread Forming Screw

A Thread Forming Screw is primarily used for installation into plastics, but can be used for metal. They do not remove any material in the creation of their thread in the housing hole.

Threaded Rod

Threaded Rod is the most common name for the fastener otherwise known as threaded bar or alltread. They are used within building, plumbing and general maintenance applications.


Titanium is a low-density metal for fasteners that is highly appreciated for use in internally and externally threaded fasteners. Often found in the automotive, aeronautical and aerospae industries.

Tricone® Security Bolt

The Tricone® Security Bolt is a unique patented product to Fastenright, accompanied by a uniquely coded and traceable to the customer driver tool. It is a premium security fastener offerin the highest possible security.


Tungsten is a high-density material, often used in fasteners that are used in the balancing of rotating parts such as propellers.


Otherwise known as a star drive, a TX refrs to a specific drive, or a screw characterised by it’s six point star shaped drive. 






U Bolt

A U Bolt is an industrial fastener shaped like the letter U. They are used to support pipework or to attach a part to a pole, beam or wall. 


The Ultra-Drive is a security machine screw wth an oversized internal pin and a unique shaped socket that repels other styles of driver.


Vented Fasteners

Vented fasteners are screws, washers and bolts that feature a hollow core to release gases and pressure through the middle of the fastener.




There are a comprehensive range of washers, which are critical in a number of applications. They aid in the distribution of the shock load of nuts, bolts, screws and other threaded fasteners. 

Wave Security Bolts and Nuts

Wave bolts and nuts are security fasteners that are ideal for high security applicatios. The drive is designed with a number of varying radiuses and angles which resist against grips like pliers. 


Waspaloy is a superalloy known for its high strength at elevated temperatures. In fasteners it is used in applications such as gas turbine engines and other aerospace components.



We haven’t found anything starting with ‘X’ as yet, but watch this space – when we do find something, we’ll add it in!


Yellow Zinc

Yellow Zinc is a protective finish layer which provides a good level of corrosion prevention. The yellow chromate that is applied increases overall protection.


Zinc De-embrittlement

Zinc De-embrittlement is a baking process to remove hydrogen atoms that may have formed between the fixing and a zinc coating, removing any hydrogen to provide a more resilient fixing.


Zirconium is a corrosion resistant metal often found in alloys. Zirconium fasteners are known for their resistance to some of the harshest acidic environments and being super conductive at lower temperatures.


If there’s someting that you think we may have missed, or there’s terminology that you can provide to us to place here, please contact us.

Featured: Pin TX Button Security Captive Screws

Available now at Fastenright, Pin TX Button Head Captive Screws feature a security drive for additional protection and are typically supplied with captive washers to create a self-retaining fastener.

Find out more information here.

Specials and non standard fixings

Looking for fixings with an unusual head diameter or thread length?
Need fasteners with a non-standard finish?

Or do you have other special requirements? Custom fasteners are no problem for Fastenright!

Fastener Terminology Glossary

There are a number of confusing names and terms within the Fastener industry, so we have created a handy terminology glossary to help.

Contact Us

The Fastenright specialist team is available to discuss your requirements.

Call us now on +44 (0)1902 457734 or complete our contact form.
We look forward to helping you.

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