What Are Machine Pins And Their Uses

What Are Machine Pins And Their Uses

Pins are a form of precision fasteners that are incredibly useful and found in various household and commercial items. Pins also exist in a limitless range of materials, conditions, and sizes. They’re often employed to align and hold parts and assemblies together.

Precision pins join two components when you shouldn’t or can’t use a threaded screw or bolt. Using pins can be intimidating initially. This article provides sufficient knowledge on where to use them and the common types of machine pins.

Where Are Machine Pins Used?

Pins are easy to come by if you look at the items around you. Automotive, electronics, aerospace, mining, and even plumbing make up the bulk of regular users of pins with the kind of precise dimensions they need. When constructed from the correct materials, machine pins form a strong connection between two metal pieces and endure considerable force.

Accurate and careful production is essential for anything requiring a machine pin. Pins are standard in sectors that need precision. Fasteners used in aeronautical and automotive applications require precisely machined pins. 

Electronics, mining equipment, and plumbing are just a few other fields that use precision pins. You can find this pin in almost all items you use daily and in various mechanical settings.

Types Of Machine Pins

Several types of machine pin fasteners see widespread use in manufacturing and other commercial settings. To know where you can use these pins, continue reading below. You can learn about their compositions, shapes, and further important details to help you purchase the right one from a reliable hardware supply.

Here are the five most common pins you see in the market today:

1. Spring Pin

Spring pins, also called roll pins, are designed by rolling a thin sheet of material, typically steel, into a cylinder. Their outside diameter corresponds to the diameter of the pin. Due to the material and its flexibility, elastic deformation is possible across various hole sizes. The chamfered ends also make it simple to push them into preexisting openings.

In the world of spring pins, you’ll find two distinct varieties:

  • Slotted Pin: Slotted pins feature a lengthwise slot into which the pins compress. Businesses or projects mainly employ them for light-duty tasks or when more precise and stable positioning is necessary.
  • Coiled Or Spiral Roll Pins: To get the sheet to coil inward toward the center, you need to make more than one complete revolution with the coil. It enables them to be constructed from thinner, more flexible material while reaching a better overall strength. Spiral roll pins are more flexible and resistant to sheer forces than slotted pins. The improved flexibility helps reduce stress concentrations and the cyclic loading that cause wear and tear, particularly around the borders of a hole. Coiled pins are well-suited to heavy-duty applications like pinning joints on earth-moving equipment.

Consider which type of spring pin works best for your use case. Suppose you plan on installing it on a device or item for light-duty tasks. A slotted pin might be more appealing to you. However, if you’re using it on a device or tool that’s required to be very durable, coiled or spiral roll pins might be a better choice.

2. Dowel Pin

A precision dowel pin is a small cylinder that maintains alignment between many parts. Dowel pins are typically machined from solid metal and made from various metals, including stainless steel and brass.

Dowel pins are common in furniture construction, but metal dowel pins are more exact than their wooden counterparts. Tapered, slotted, spiraling, and grooved dowel pins are all precision-made options. Dowel pins also have applications in different industries. In recent studies, they’re trying to use dowel pins within the dental industry

However, dowel pins require holes to be carefully reamed and aligned due to their rigid nature. Dowel pins are standard in jigs and other precision equipment to ensure that holes are drilled precisely in the center. Dowel pins are solid and transmit sheer forces well. It’s best to have some spares in your toolbox for future use.

3. Grooved Pin

The primary difference between grooved pins and dowel pins is the presence of axial grooves, which are often three grooves on the surfaces of the former. It’s not uncommon for some manufacturers to create grooves down the pin’s length. The grooves facilitate compression, allowing it to fit more snugly into tighter locations.

4. Cotters

Cotters are rigid, flat-faced pins with a slight taper. You can insert them safely into holes of varying sizes, thanks to this slight taper. If the pin has a threaded end, you can secure the nut to the flat face to keep it from turning. They no longer hold themselves in place due to friction within the hole. The term ‘cotter’ also refers to simple wedges without cylindrical faces used to fasten components by being driven into a hole.

5. Split Pin

The bendable material used to make a split pin is cut in half to create a circular shape. Both ends are curved inward such that the overall shape is roughly round. There’s a substantially circular head at the curved end. The two tines at the other end can be pushed through a hole and bent over to prevent removal. 


Sufficient knowledge is key to avoiding mistakes, especially in business. Like all things, as long as you do your due diligence, it can lessen your financial difficulties.

Choosing the correct machine pin can be challenging, especially considering the various types. Additionally, this article hasn’t mentioned other pin types. Check them out as well. Technology develops at a rapid rate, and it may be beneficial to you to continue learning more and more about the things that may be related to your business or profession. 

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