Guide to Machine Pins, Pin Fasteners, and Industrial Pins

Types of Machine Pins
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Specialize in CNC Milling, CNC Turning, 3D Printing, Urethane Casting, and Sheet Metal Fabrication Services.


Machine pins are available in a wide variety of configurations and are often used in various applications. Pin fasteners perform the same functions as other types of fastening devices in some circumstances, such as assembling two components. Still, the unique characteristics of industrial pins distinguish them from other types of hardware. In this piece, we discuss the many types of pins, particularly emphasizing the properties and applications of the various kinds of machine pins.

What Exactly Are Machine Pins?

Machine pins are a hardware type and fastener used to secure two pieces of material together. They can be either semi-permanent or quick-release, with the former requiring additional force or specialized tools for assembly and disassembly and the latter featuring a spring-loaded framework that secures the pins into place and makes installation and removal simple. Steel, copper, brass, wood, polymer, and many more materials may all be used to create pins.

Our CNC machining services can provide the perfect pin for any application, whether you need lightweight, pliable, highly conductive aluminum pins, low-cost, corrosion-resistant plastic pins, or pins made of any other material for industrial use.

Various Types of Machine Pins

Cotter Pins

Cotter pins are wired shape fasteners that are often used in applications related to machine assembly. They are a locking mechanism to keep pins or nuts in their proper positions. The word “cotter” is synonymous with the British phrase “cotter pin,” which is used in the United States.

Another use of the word “cotter pin” is the “crank cotter pin,” a locking mechanism used to attach the pedal cranks of a bicycle to the bottom bracket axle. Cotter pins may be broken down into subcategories, including circle cotter pins, hairpin cotter pins, extended cotter pins, and ring cotter pins. The configurations of these many subcategories of cotter pins are quite distinct from one another.

Cotter pins

Dowel Pins

Dowel pins fall into various categories due to their straight, cylindric solidity and the variety of end shapes available (taper, slot, helix, step, groove, etc.).

Dowel pins serve primarily as insertion and alignment aids before the application of additional fasteners. Drive pins (with an interference fit and needing to be guided into place, typically used in rotary applications), grooved pins (with longitudinal grooves that provide a larger surface area for adhesive and increased power), and knurled pins (with a knurled surface for firm grip) are all examples of dowels.

Dowel pins

Spring Pins

Spinning pins or roll pins, sometimes tension pins, have a greater body diameter than the hole diameter with a chamfer on one or both ends to make insertion into the hole easier. Dowel pins are sometimes referred to as spring pins, and they may either be rolled or coiled depending on the use.

Both coil spring pins and rolled spring pins begin as cylindrical shapes that are then coiled and rolled, respectively. Machines often include spring pins that lock the precise location of two or more pieces of the machine to one another.

Spring pins

Hitch Pins

Hitch pins are convenient fasteners that are often used to attach agricultural equipment and vehicle trailers. They also make it easier to remove and replace the fasteners. On vehicles, larger hitch pin dimensions are used so that a trailer ball mount may be safely attached to a receiver hitch.

Hitch pins

Linch/Lynch Pins

Like hitch pins, lynch pins are intended to keep a wheel or other spinning device securely attached to its axle. However, they are also useful as a kind of fastening. Quick-release, cylindrical, straight pins called hitch pins and lynch pins are both used to secure trailers to towing vehicles; both types of pins are often found on vehicle trailers and need matching holes or some other sort of lock. Unlike nuts and screws, these tools are designed to withstand shear stresses.

Linch pins

Locating Pins

Locating pins are intended to align or secure two workpieces to highly precise tolerances, depending on the application. When translation techniques are unreliable or precise enough to hold items in place for a given procedure, locating pins may help guarantee that the objects are aligned correctly.

Using locating pins is a terrific technique to ensure that the components you are putting together will fit together in the manner that you want them to fit together. A wide variety of shapes and combinations are available for locating pins, including a variety of heads and shanks to choose from. In most cases, using just two locating pins is sufficient for accurately positioning the workpiece on a single plane.

Locating pins

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Runsom is delighted and able to accept special variations beyond the standard product. Request an instant quote to learn more about our machining capability of Quick Release Pins today.


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