Fasteners are known to be devices that are used for creating a strong joint in different applications. Most fasteners allow joints to be dismantled or removed without damaging the joined parts while some are permanently joined.
Fasteners serve better as the joint can be removed or dismantled without damaging the joining components, although some fasteners like rivet bonds permanently except that the rivet itself will be destroyed for the joint to be dismantled. Well, in this reading, we’ll explore the different types of fasteners and their uses.
Let’s get started!
Types of Fasteners
Metal fasteners are of two kinds: permanent and non-permanent bond. The permanent fasteners cannot be dismantled when joined except the fastener will be destroyed and cannot be reused. On the other hand, non-permanent fasteners can be removed and reused as required. However, the various types of fasteners are bolts, screws, nuts, washers, Rivets, inserts, retaining rings, and concrete anchors.
1. Bolts
Bolts have a head on one end, usually a hex head, and are threaded on the other. Bolts are generally used in conjunction with a nut and sometimes with a washer to hold them in place. The common types of bolts include:
a. Carriage bolts
Carriage bolts are also known as a coach bolt, having a domed or countersunk head. A square section beneath the head grips into the material, preventing the bolt from turning when the nut is tightened.
b. Hex head bolts
Hex head bolts are the most common types of bolts, having hexagonal heads and are driven with a wrench. Hex tap bolts, hex cap screw, trim head hex cap screws, and hex serrated flange bolts are hex head bolts.
c. Machine screws
These types of bolts are screw or bolt with flat points, having a variety of drive types and heads. They are often driven into tapped holes used along with nuts and washers. Machine screws are also known as stove bolts or stovers.
d. Shoulder bolts
Shoulder bolts are also known as stripper bolts or shoulder screws. They are machine screws with a shoulder between the thread of the screw and the head of the part. The non-threaded portion in this bolt extends out of the surface of the application, making it act as dowels or shafts for moving parts.
e. Socket cap screws
socket cap screws are available in button socket, button flange socket head, flat socket, and socket cap. The term socket head cap screw typically refers to a type of threaded fastener whose head diameter is normally 1.5 times or more than that of a screw shank diameter.
f. Socket set “Grub” screws
These types of fasteners are fully threaded and have no head. It is driven into material using an internal wrenching drive known as hex Allen key.
g. Squarehead bolts
Similar to hex cap screws but have 4-sided head. This allows a wrench to grip more easily onto the head of the bolt. This head also provides a larger gripping area as compared to a standard 6-sided hexagonal head.
2. Screws
screws are similar to bolts because they also have a head on one end and a thread on the other. Screws are usually used to screw into an internally threaded hole. Cap screws, machine screws, and woodscrews are the different types of screws available. Types of screws include:
a. Deck screws
Deck screws are easily installed in wood and composite deck materials. Their stripping effect can be eliminated with a bugle head and squarer drive.
b. Hex lag screws
These types of fasteners are also called lag bolts. Their head has an external hex and is driven with a wrench, used for lagging together lumber for frame, machinery to wood floors, and other heavy-duty applications.
c. Self-drilling screws
Self-drilling screws are types of screws having sheet metal thread with a self-driller cutting point to pierce through 20- to 14-gauge metals.
d. Sheet metal screws
sheet metal screws have sharp cutting threads that cut through sheet metals, plastics, or woods. They have a fully threaded shank and sometimes have a notched point at the tip which helps to remove the chip during the process.
e. Wood screws
Wood screws are types of screws partially threaded with large cutting threads and a smooth shank. They are designed to slide through the top piece of wood and tightly pull all boards together.
3. Nuts
Nuts are used in conjunction with a bolt to clamp two or more parts together. Common types of nuts include:
a. Cap nuts
Cap nuts also known as acorn nuts due to their shape. it has a domed top to prevent contact with the external thread.
b. Castle nuts
Castle nuts are types of nuts used with cotter pins to prevent loosening. It is also called a castellated or slotted nut. It is used in low-torque applications, for instance, holding a wheel bearing in place.
c. Coupling nuts
Coupling nuts are threaded fasteners types used for joining two male threads, most commonly threaded rod. A wrench can be used to drive them nuts because their outside is a hex.
d. Flange serrated nuts
flange serrated nuts have a wide flange at one end acting as an integrated washer that does not move or spin. This serrated flange distributes the pressure of the nut over the part being secured. It also creates a locking action to prevent loosening.
e. Hex finish nuts
Hex finish nuts are types of fasteners used for fastening to a hex cap screw, socket cap screw, or bolt. They are also driven with a wrench.
f. Hex jam nuts
Hex jam nuts are used when locking in place is required without clamping to another object. These types of nuts are hex shape with internal threads, but they are thinner than hex finish nuts.
g. Heavy hex nuts
Heavy hex nuts are heavier, thicker, and larger than normal hex nuts. They are internally threaded with hex-shaped, often used with hex cap screws and carriage bolts.
h. Hex machine nuts
Hex machine nuts are hex-shaped with internal threads. They are smaller than a hex jam or hex finish nut, used with machine screws under 1/4” diameter.
i. Hex machine nuts small pattern
Hex mahcine nuts small pattern is also hex-shaped with internal threads, smaller than a hex jam or hex finish nut.
j. Keps-K lock nuts
Keps-K lock nuts are also known as keps nut, k-nuts, or washers nuts. These types of fasteners have an attached free-spinning lock washer. They are designed to make assembly more convenient.
k. Knurled thumb nuts
Knurled thumb nuts has a knurled outside surface instead of hex, which can be tightened by hand. It is often used as decorative finishes or applications.
l. Nylon hex jam nuts
Nylon hex ham nuts are low-profile lock nut hex-shaped, internally threaded with a nylon insert. The nylon material prevents loosening from vibration and cross threads to stop the nut from backing off of the fastener.
m. Nylon insert lock nuts
These types of fasteners are hex-shaped and are internally threaded with a nylon insert. This nylon material prevents loosening from vibration and cross threads to stop the nut from backing off the fastener.
n. Prevailing torque lock nuts (stover)
These types of nuts are chamfered in their corners and have a conical top. The distortion at the top threads’ resists loosening from vibration. They are also called one-way nuts, that is, they can only be installed one way. Stovers are often used in high-temperature applications because there is no nylon insert, all its body is metal.
o. Slotted hex nuts
These nuts types are with a portion cut out in order to be used with a cotter ping to create a locking mechanism. These nuts are much similar to a castle nut, only that they have a lower profile which sometimes makes them a better option.
p. Square nuts
Square nuts are types of fasteners with four sides and may be flat or beveled at the top. They offer a greater surface contact area, which makes them more resistant to loosening.
q. Structural heavy hex nuts
Structural heavy hex nuts are comparable to finish nuts but are designed to be stronger and thicker. They are often used in steel-to-steel structural connections.
r. T-nuts
T-nuts are used to fasten wood, particle, or composite board leaving a flush surface. T-nuts often have 3 or 4 prongs that enter the surface providing better retention.
s. Breakaway or shear nuts
Breakaway or shear nuts are cone nuts with a hexagonal gripping point, designed with an intentional flaw to snap the hexagonal head off once the maximum torque is reached.
t. Tri-groove nuts
Tri-groove nuts have a tapered diameter making them inevitable to grip with grabbing devices like adjustable wrenches or pliers. A special unconventional gripping device to install them making them more secure than a typical nut.
u. Wingnuts
Wingnuts are types of threaded fasteners with wings on each side of the body allowing for manual turning and installation. They are used on applications where the nut will be often removed, which is why it can be easily loose and tight by hand.
4. Washers
Washers are types of fasteners used between the had of a bolt, screw, and nut to clamp material together. Their primary purpose is to increase the bearing area of the head and also protecting the material underneath from damage. Below are the different types of washer and their uses.
a. Backup rivet washers
Backup rivet washer are used to create a larger install diameter, which gives the rivet a better hold and support. These types of washers help to prevent the pull-through of rivets.
b. Belleville conical washers
Bellevile conical washers are types of washers that add extra tension to a joint assembly. They are used in stacks to increase the load, deflection. These fasteners types are also considered lock washers since they add tension and can absorb vibration from the assembly.
c. Dock washers
Dock washers are heavy-duty washers, used often in docks building. They are also used in heavy-duty construction that requires thick washers. Well, dock washers are similar to fender washers with a small inside diameter hole.
d. Fender washers
Fender washers are round washers with small inside diameter holes. They are used to prevent pull-through and provide a greater bearing surface under the fastener.
e. Extra thick fender washers
Extra thick fender washers are also round washers with a small inside diameter hole, just that the thickness of the washer is more than the standard fender washers. They are used to prevent pull-through and offer a greater bearing surface under the fastener.
f. Finishing cup washer
These types of fasteners are in form of a cup so that the head of the screw or fastener can fit in. They create a finish flush with the top of the head. This is why they are used for finishing.
g. NAS washer
NAS washer is a round washer with a smaller inner and outer diameter. It is often used in military applications due to its strict measurement specifications.
h. Neoprene EPDM washer
Neoprene EPDM washer is also a round washer that is slightly beveled with a neoprene lining. It is often used with sharp points and self-drilling TEK screws to make a watertight seal around the screw or metal roofing or siding.
i. Structural washer
Structural washer is thick and strong, used for heavy-duty applications. This washer is used in steel beams and girder fastener assemblies.
j. Square washer
Square washer has a square shape and may be flat on both sides or one on the side and beveled on one side. This washer is often used with square head bolts. It prevents pull-through and provides a larger surface area and greater hold than standard round flat washers.
k. Flat washers
Flat washers have round outer diameter thin plates containing a punched center hole that let the bolt or screw in. these washers are used to distribute loads of threaded bolts, screws, and nuts evenly as the fastener is tightened.
l. Extra thick flat washers
Extra thick flat washers are thicker than the standard flat washers. They have round outer diameter thin plates with a center hole punched to the size of the bolt or screw.
m. Military standard flat washers
Military standard flat washers are types of fasteners that undergo extensive inspection for chemical, physical and dimensional qualities. MS washer types must meet specific inner diameter and outer diameter specifications.
n. 900 series flat washers
900 series flat washers are round and thinner than a standard flat washer with a smaller inside and outside diameter.
o. Split ring lock washers
split ring lock washers are types of washers used to prevent nuts, bolts, and screws from vibrating loose. These washers are rings that are split at one point and bent into a helical shape.
p. High collar lock washers
High collar lock washers are designed to fit under the head of a socket cap screw. They are also used to prevent nuts, bolts, and screws from vibrating loose. These washers are rings that are split at one point and bent into a helical shape.
q. External tooth lock washer
External tooth lock washer is used for locking and tensioning. This washer is round with teeth on its outside, making it hold maximum power. It must be used with a fastener with adequate head diameter.
r. Internal tooth lock washer
Internal tooth lock washer is a round washer with internal teeth, designed to prevent a nut or screw head from loosening with the struct action created by the teeth. It is used for locking and tensioning.
5. Rivets
Rivets are permanent fasteners, that is, when removed, they cannot be re-used. Rivets are used in some industries and for some special applications. However, they are commonly used to join metal sheets and plates. Multi-grip rivets
These types of fasteners are used when joining materials with different thicknesses. Normally, the materials will be required multiple rivet sizes. Multi-grip rivets are very versatile and cost-effective. Below are the common types of rivets:
a. Pop rivets (open end)
Pop rivets are known as blind rivets, used to connect two pieces of material in a quick, efficient way. These rivets are tubular, having hats and mandrels.
b. Closed-end pop rivets (sealed)
These types of fasteners are differs from a standard blind pop rivet because they feature a closed-end which creates a watertight seal.
c. Large flange pop rivets
Large flange pop rivets are types of fasteners called oversize pop rivets having larger washers on the hat than a standard pop rivet. They are also known as blind rivets used for connecting two pieces of material in a quick, efficient way.
d. Countersunk pop rivets
Countersunk pop rivets also known as flat pop rivets, used for connecting two pieces of material with ease, quick and efficient way. The rivets are tubular, comprising of hat and mandrel. The mandrel’s length is snapped off when installed.
e. Colored rivets
Colored rivets are types of rivets having their hat painted either brown, black, or white. The color helps to hide the rivets and create a finished look. It also makes the rivets extra visual by using the opposing color from the installation material.
f. Multi-grip rivets
Multi-grip rivets are types of rivets used in substitution of conventional rivets where the thickness of installation materials varies. These rivets can simply expand to the size (within its range) and hold the material together.
g. Structural rivets
Structural rivets are used to create a stronger assembly than normal stainless-steel pop rivets. They create an intense amount of force and a different tool is required to install the fasteners.
h. Tri-fold rivets
Tri-fold rivets are types of rivets also called exploding rivets, having three cuts in the hat that causes the hat to fold outward when installed into three distinct wings. These rivets types offer better strength and holding power than standard pop rivets.
6. Inserts
Below are the various types of inserts:
a. Dowel pins
Dowel pins are cylindrical with slightly beveled ends, manufactured on pneumatic dowel equipment. They come in pre-cut length and diameters and are used in many applications. Industries like aerospace also make good use of dowel pins. These pins are used in joint reinforcement, shelf support, furniture build. Hobbyists use them to build toys and models.
b. Helicoil threaded inserts
Helicoil threaded inserts are precision-formed screw thread coils in a diamond shape and wound into a spiral coil. It is installed into Helicoil tapped holes. These types of inserts offer permanent conventional 60-degree internal screw threads. These inserts are larger in diameter prior to installation.
c. E-Z Lok threaded inserts
E-Z lok threaded inserts requires special drilling, unlike Helicoil. They are used for metal using standard tools. Stainless steel threaded inserts are used for metal applications, and brass types are used for wood and soft material applications.
d. Keystock
Keystock is a solid rectangular-shaped solid bar stock. It is often machined into a machine key, serving as a wedge.
e. Threaded rod
Threaded rod is threaded with no head, available in many grades and materials. They are used for fastening anything from anchor bolt, to suspending electrical or plumbing equipment from a ceiling.
f. Unthreaded rods
Unthreaded rods are also called a round rod, used in framework, shafts, braces, supports, and axles.
7. Retaining Rings
Retaining rings are circular metal fastener that are used to hold parts together. These rings are used for clamping around a shaft or inside a bore. They are also known as snap ring or circlips.
These types of fasteners are cost-effective and are one of the efficient way to hold components axially. This is why they are commonly used in manufacturing and engineering. The common types of retaining rings are:
a. Bowed-e retaining rings
Bowed-e retaining rings are designed to be installed into a groove on a shaft. The clips exert force to the material once snapped into the groove or preload on retained parts in order to compensate for accumulated tolerances.
b. e-style retaining rings
E-style are types of retaining rings designed to use the style of the radial retaining ring. They are called e-rings because of the three prongs on the inside of the shaft which make contact with the bottom of a groove. The groove on a shaft creates a shoulder for effective assembly retention.
c. External shaft retaining rings
External shaft retaining rings are designed to be used in a groove or shaft. A portion of the retaining rings protrudes from the groove in order to create a shoulder to keep an assembly. This occurs once installed in a groove on a shaft.
d. Internal housing retaining rings
Internal housing retaining rings are designed to be also used in a groove on a shaft. It is installed in a bore or housing, a portion of these retaining rings protrude from the groove in order to create a shoulder to keep an assembly.
8. Concrete Anchors
Concre anchors are types of fastener that are used to attach object to concrete. They are used in applications for hanging cabinets, securing heavy machining, and fastening concrete building together.
These kinds of fasteners are also known as male fasteners. They are made up of threaded bolt, an expander sleeve, a washer, and a nut.
In their working, a hole is drilled in the part such as concrete, brick, mortar, or stone, the sleeve anchors can be threaded through the fixture and set. The common types of anchors include:
a. Acoustical wedge anchors
Acoutical wedge anchors are types of fasteners used to anchor and secured suspended wire to solid or hollow masonry materials. The fasteners are inserted into a pre-drilled hole and then struck with a hammer.
b. Drop-in anchors
Drop-in anchors are internally threaded anchors that are installed overhead and flush with the surface of the concrete. These types of fasteners are used to create handrails, lighting fixtures, and many other fixtures.
c. Double expansion shield anchors
Double expansion shield anchors are designed for softer material installation or that of low quality. Their entire length expands in the hole to create a very secure hold. The expansion maximizes friction and holds on to the installation material.
d. Hammer drive pin anchors
Hammer drive pin anchors are used for lighter loads than other types of concrete anchors. Drive pins apply fixtures to masonry materials. Hammers are used to driving the exposed head of the pin, which expands the base inside of the masonry material creating a hold.
e. Kaptoggle hollow wall anchors
Kaptoggle hollow wall anchors are installed through a hole in walls or block. It securely holds to the wall as a machine screw is used. These types of fasteners are proven to have better holding power than conventional types.
f. Lag shield expansion anchors
Lag shield expansion anchors are shielded expansion anchors used to hold lag screws. They expand outwards as lag screws are driven into them. This expansion press against the installation surface creates a tight and secure hold. These types of fasteners also have very precise internal threading to allow the installation lag bolt to turn easily.
Machine screw anchors
Machine screw anchors are types of anchors installed into masonry materials in a pre-drilled hole. They are placed inside the hole and a machine screw is threaded into the anchor and tightened. A coned portion is pulled into the sleeve causing it to deform. This deformation of the sleeve results in a tight wedge inside the hole that cannot be removed easily.
Masonry screws
Masonry screws are also known as Tapcons, cut threads into concrete, brick, or block when installed. These screws have extended corrosion protection is gained from the blue climaseal coating. No hole spotting or insets is needed here.
Plastic toggle anchors
These are types of fasteners used in hollow walls or cinder blocks to create a fastening point for sheet metal screws. These types of anchors have legs that fold to enter a pre-drilled hole that expand when a screw is driven into them. As soon as the legs fully expanded, the toggle anchor is securely in place.
Sammy screws
These screws are used with threaded rods and save time by drilling into masonry materials. They feature a female threaded portion to accept the threaded rod into it. These screws are installed vertically or horizontally. They are commonly employed due to their lower installation costs, flexibility, and ease of use.
Sleeve anchors
Sleeve anchors consist of a threaded stud with an outwardly flared cone-shaped end, with a nut and washer on the end. The stud is pulled into the expander sleeve as the nut is tightened. This wedge outwards and locks the anchor into the base material.
Toggle wing hollow wall anchors
Toggle wing hollow wall anchors are used when installing through materials. The wing can be bent in haft and pushed through the material. Once it finds its way through the material, it expands and a screw will be used to hold it in place against the rear side of the material.
Wedge anchors
Wedge anchors are used to anchoring and secure materials and equipment to solid concrete masonry surfaces. These types of anchors consist of anchors, nuts, and washers. They are used to fasten concrete to equipment, materials, motors pipe, strut, plastics, wood, and generators.