A guide to fastener pins
Each fastener has a specific purpose, including fastener pins for industrial uses. We’ve put together this guide to explain what they are, the different types of pins, and what they’re used for. To help you understand these critical components, we’ll cover:
What are fastener pins?
Fastener pins are pieces of fastening hardware commonly known as machine pins, a name that hints at their purpose. As you can see in the drawing here, they have a cylindrical shape and are typically non-threaded. These pin fasteners insert into holes to mount, assemble, align and connect parts and components where shear force is a factor.
Industrial fasteners generally belong to one of two main categories:
- Quick release pins
- Semi-permanent pins
Quick-release types of pins are self-contained, while semi-permanent pins require pressure and tools for both installation and removal. Fastener pins with a quick-release component lock into place for a secure hold with a spring-loaded mechanism. These are ideal pin types for applications that involve frequent adjustments, such as temporarily securing machine parts to carry out maintenance. Otherwise, semi-permanent are a good choice.
How do fastener pins work?
Fastener pins are inserted into non-threaded holes in the two components they’re joining. Usually friction or tension is required to hold these inserts securely in place. They impede shear force, which are opposing forces that push one area of the pin in one direction and another area in the opposite direction. For this reason, they’re often used to make rotational joints.
Fastener pins also prevent axial movement to keep the assembly in alignment. Note – when strong axial force is at play, you should use bolts.
Types of fastener pins
Below are the many types of fastener pins, manufactured in different metric sizes and materials. You can choose from several types of metal pins and even plastic. We’ll first introduce you to the different pin types and in the next section, explain their applications.
Spring plungers – pull ring/hand retractable
A threaded example, used for positioning as loading pins, alignment pins, and indexing devices.
- Ideal fastening pins for limited space applications
- Lock-out feature keeps pin plunger in retracted position to allow user to make final adjustments to equipment using two hands
- Anti-vibration lock patch also available – can be added on to threads
- Pin material: steel
- Plating: clear zinc
These industrial pins combine the best of cotter pins and clevis pins. They’re a convenient way to adjust or remove accessories on equipment.
- Easy installation and removal - pull the wire loop over the pin to lock it in place and reverse the process for easy removal
- Available in standard lengths and common retainer clearance dimensions
- Material: steel
A detent pin is used to adjust or separate joined accessories and equipment. This pin fastener is designed with industry standard diameters, featuring a convenient pull-ring for ease of use.
- Chamfered tip assists in quickly locating a hole
- Convenient and economical
- Also available threaded
- Available materials:
– Low carbon steel for strength and durability
– Stainless steel for strength and corrosion resistance
Locking pin types offer a quick way to make adjustments on equipment. These lynch pin clips are inserted through an axel to keep components from falling off.
- Self-locking ring snaps are used to secure the assembly
- Allows for fast, easy removal
- Material: Steel for maximum strength and plated with zinc – yellow dichromate for corrosion resistance
Fastener pins designed for optimal control and gripping.
- Fitting ring on the handle allows for easy attachment of an optional wire lanyard, or a wire rope lanyard, to help prevent loss
- Ball locking pins enable excellent retention, safety and dependability
- Also available in T-handle
- Materials:
– Handle and button, cast aluminum
– Pin, stainless steel or low carbon steel
Weld mount retractable spring plunger ball
Types of fastening pins also include ball-style retractable spring plunger pins.
- Weldable cylinder
- Available with or without lock-out features – lock-out feature holds pin in retracted (open) position to enable user to use both hands to make adjustments
- Three tips available: standard straight, short tip, and tapered tip
- Materials:
– Pin: steel, case hard
– Pin plating: clear zinc
– Knob polypropylene (PP)
– Barrel: steel (plain plating)
You can learn more in our Guide to panel fasteners or read What’s the difference between metric and standard fasteners.
Fastener pin applications and uses
Now that you’ve seen the types of pins in mechanical engineering, the next question is, what are pins used for? You’ll find them in a range of industries with different functions. For heavy-duty operation, metal is your best bet, such as steel and stainless steel – especially for marine uses for its corrosion resistance. For architectural applications, brass is a good choice when aesthetics are the focus.
Automotive and specialty vehicles
- Clevis pins
- Coiled pins
- Cotter pins
- Dowel pins
- Lynch pins
- Pin retaining cables
- Spring plungers
- Weld mount retractable spring plungers ball
Pin-fastener types vary for this application. Cotter-pin uses are most common in vehicles, specifically for preventing axial movement along a shaft. That is, they secure wheels and other components on an axle or shaft. A motorcycle front wheel is one example. Vibrations are a concern, so the wheel is held on with a castle nut and a cotter pin to ensure it stays secure.
Likewise, lynch pins are used in off-road vehicles. For instance, they’re commonly used to secure implements onto a tractor’s three-point hitch. They also secure the tailgate of a trailer. The pin passes through the tailgate catch and the loop snaps shut.
Clevis pins are essential to a car’s braking system, shock absorber, and rod end for gas struts. These pins are used in steering wheels in the marine industry, which shows you how versatile they are.
Clevis pins are an ideal fastener pin for towing equipment by securing a moveable component between two workpieces that mate. For instance, they fasten and secure loads to construction vehicles, pickup trucks, and trailers – they even serve this purpose for aircraft. They’re secured in place by cotter pins or pin retaining cables that insert into the clevis pin’s slot.
Coiled pins are often used in brake cylinders or seat adjustment mechanisms, and even flick-style key fobs. They’re also found in door handles, trunks, gas struts, sunroof assemblies, and glove compartments.
Weld pins are often used in body applications that require structural rigidity, such as body-to chassis-fastening.
A spring plunger is often used in EV chargers to hold the gun in the socket. Dowel pins are used in DC fast chargers, while threaded inserts are also used in EV batteries to fasten the housing together.
Machines and equipment
- Cotter pins
- Clevis pins
- Detent pins
- Dowel pins
- Quick release pins
- Spring plungers
- Wire lock pins
- Weld mount retractable spring plungers ball
With their cylindrical shape, dowel pins are the simplest of fastener pins. They align a machine’s components before those components are fixed together with screws, bolts or rivets. For instance, so that you can drill holes into the machine as needed, the machine has to align properly. Dowel pins are used to align and hold the parts while you drill and screw.
Dowel rods aren’t limited to one application. They’re also excellent as structural reinforcements for cabinets and as spacers in electronic equipment.
For machines with gear shafts – such as those that require grinding operations – cotter pins are excellent engineering pins, used to lock gear shafts in place so that maintenance or adjustments can be undertaken.
A clevis pin is often used in textile machinery and for other machines that vibrate. Clevis pins, as already mentioned, also use a cotter pin to secure it in place. Wire lock pins offer another fastener pin option, doing both the job of both clevis and cotter pins.
A weld mount retractable spring plunger ball is also called a spring-loaded plunger or pop pin. It’s used as a convenient and quick way to adjust height or length for a range of machines and equipment, commonly racking systems and fitness equipment.
Quick release pins are mostly used on machines and equipment that require fast, frequent and manual assembly and disassembly. In the example of this quick release pin, a spring-loaded ball shoots out of the pin shaft into a hole (or detent), which locks the pin place via pressure from the spring.
To remove the pin, the operator presses the button, seen here on top of the handle. The button releases the spring pressure, which then unlocks the pin for removal.
Detent pins are another type of quick release pin and they work the same way for machines and equipment. These fastener pins, however, are designed to be more difficult to remove so that pinned parts remain secure in heavy use.
Finally, spring plungers are used as permanent clamping elements. They’re especially useful for fastening sliding elements, such as a locking pin.
Solar energy
- Dowel pins
- Indexing pins
- L-handle quick-release pins
- Pull rings
- Spring plungers
- T-handle quick-release pins
Fastener pins are also used as solar panel hardware, specifically in the frames. They’re used as a manual fixing point for adjusting height and angle or securing multiple materials to prevent movement. They also ensure easy assembly and removal when adjustments are needed, such as creating new planes within frames.
Medical equipment
- Cotter pins
- Dowel pins
Dowel pins are handy for devices such as surgical retractor holders and scissor-style forceps. In these types of forceps, a hinge joins the two main parts near the center of the tool. Without this hinge, the two components cannot open and close. The hinge in this case is actually a dowel pin.
Stainless-steel cotter pins are typically used when sanitary conditions are critical, such as anaesthesia breathing systems.
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