Technical Overview of Lynch Pins (Linch Pins, Quick Pins, Snapper Pins, Click Pins)
Lynch pins, also known as linch pins, quick pins, snapper pins, or click pins, are simple yet highly effective fasteners widely used in agricultural, industrial, and transportation applications.
Their design allows for rapid assembly and disassembly, making them a go-to choice when safety, convenience, and reliability are critical. From securing tractor implements to locking trailer couplers, lynch pins are valued for their strength, durability, and ease of use.
Key Takeaways
- Lynch pins are quick, durable fasteners used in agriculture, industry, and transportation
- Shanks are usually low carbon steel for cost-effectiveness; rings are high carbon steel for strength
- Corrosion protection comes from zinc plating or full stainless steel versions
- Standard sizes range 3/16”–7/16”; larger heavy-duty applications often use alternatives like hitch pins
- Commonly tethered to equipment for frequent use in harsh environments
Materials and Construction
A standard lynch pin consists of two main components: the shank and the ring. Each serves a unique function and requires different material properties.
Shank (Body)
- Material: Most lynch pin shanks are made from low carbon steel (typically 1008–1018). This steel is ideal because of its:
- Formability – excellent for cold forming
- Cost-effectiveness – economical compared to higher alloy steels
- Toughness and flexibility – strong enough to endure repeated use
- Higher Strength Options: For demanding applications, medium carbon steels (such as 1045) or alloy steels can be used. These materials are well-suited to through hardening, which significantly increases the shear strength of the lynch pin. This makes them a preferred choice when the fastener must withstand greater loads, impact forces, or repetitive stress in heavy-duty assemblies.
- Manufacturing Method: Shanks are typically cold formed, a high-speed process where cold-drawn wire is forcefully upset in a die to achieve its final shape.
- Advantages: Economical, consistent dimensions, and enhanced strength due to cold working.
- Limitations: Cold forming becomes more difficult as pin diameters exceed 5/8” or lengths approach 5”.
Ring
- Material: The ring requires higher strength and spring-back properties. For this reason, it is made from high carbon steel that is hard-drawn to achieve high tensile strength.
- Functionality: The ring’s offset design applies torque that keeps it flat against the shank when closed.
Corrosion Resistance
Since lynch pins are often exposed to outdoor elements like mud, grit, and moisture, corrosion resistance is essential.
Plating Options
- Zinc Yellow (Hexavalent) – offers superior protection compared to zinc clear/silver (trivalent).
- Supplementary Sealers – can extend the lifespan of zinc coatings.
Stainless Steel Options
For maximum durability, lynch pins can be manufactured entirely from 300 series stainless steel, offering excellent resistance to rust and long-term outdoor performance. Pivot Point carries fully stainless steel lynch pins as a standard offering, in addition to our plated lynch pins.
Even when rust sets in, lynch pins generally continue to function due to their robust and straightforward design.
Sizes and Variability
Lynch pins are manufactured in a wide range of diameters and lengths, depending on the application.
Common Sizes
Diameters typically range from 3/16” to 7/16”.
Customization
Larger or longer pins can be produced, though shanks larger than 7/16” are uncommon.
In applications requiring larger, heavier-duty fasteners, alternatives such as hitch pins, bent-arm pins, or grab-handle style pins may be more suitable than a very large, customized, lynch pin.
Applications
Lynch pins can serve as standalone fasteners, installed through stand-offs or tabs to prevent material layers from separating.
They are also frequently employed as a heavy-duty alternative to traditional cotter pins, used in combination with larger fasteners such as bent-arm pins, hitch pins, or grab-handle style pins - particularly in applications where smaller cotters are impractical or insufficiently durable.
Frequent Installation & Tethering
Because lynch pins are often installed and removed frequently, they are commonly tethered to equipment using:
- Wire rope lanyards
- Injection molded nylon lanyards
- Chains
This prevents loss and improves usability in demanding environments like agriculture, forestry, and construction.
Why Use Lynch Pins and What For?
Lynch pins (also spelled linch pins, quick pins, snapper pins, and click pins) are essential fasteners across a wide range of industries due to their strength, quick-install functionality, and durability in harsh environments.
Built from a combination of cold-formed low carbon steel shanks and high-tensile steel rings, they provide a reliable fastening solution that balances cost-effectiveness with robust performance.
For more demanding applications, through-hardened medium carbon or alloy steels deliver even greater strength and longevity. Whether zinc-plated for general use or made entirely of stainless steel for maximum corrosion resistance, lynch pins remain a trusted choice for securing equipment and assemblies quickly and effectively.
Frequently Asked Questions About Our Lynch Pins
Here are some common questions about lynch pins and how to use them.
What is a lynch pin used for?
A lynch pin is used to secure equipment, components, or assemblies where quick installation and removal are required - commonly on trailers, tractors, and agricultural machinery.
Are lynch pins the same as snapper pins or click pins?
Yes, lynch pins are often referred to as snapper pins, quick pins, or click pins. The terms are interchangeable, describing the same style of self-locking pin.
What sizes do lynch pins come in?
Common sizes range from 3/16” to 7/16” in diameter, though custom sizes can be produced depending on application requirements.
Can lynch pins be used outdoors?
Yes. Most lynch pins are zinc-plated for corrosion resistance, and stainless steel lynch pins are available for maximum durability in harsh, outdoor environments.
What materials are lynch pins made from?
Typically, the shank is made from low carbon steel, though medium carbon and alloy steels are used for higher strength. The ring is made from high carbon steel for spring action.
Different Use Cases for Lynch Pins
Below you will see images of different use cases of how our customers use lynch pins from Pivot Point.
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