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8 Different Types of Pins

Several types of retaining pins.

When you need to fasten or align two components, there are many hardware solutions available to you. One common option is pins, which fit into pre-drilled holes and make up their own class of fasteners. There are numerous types of pins, and all of them operate a little differently to suit different situations.

Due to their many design options and ease of use, pins are popular fasteners. Let’s look at a few of the more common types.

1. Linch Pins

Linch Pin

Linch pins have their own built-in locking mechanism in the form of a loop that runs through the head of the pin. Once the pin is inserted, the loop snaps down, holding the pin in place.

2. Cotter Pins

Cotter pin

Made of a softer, more pliable metal, cotter pins are similar in shape to a bobby pin, but they’re straight on both sides. Once a cotter pin is inserted through a hole, its legs are bent back to keep it from falling out.

3. Hair Pins

Hair pin

Like cotter pins, hair pins consist of one continuous piece of metal that’s straight on one side and curved at the top, but they’re made of a firmer substance so as to remain stiff. The straight leg of the pin is inserted into a hole while the other holds it in place.

4. Clevis Pins

clevis pin

These pins have a machined head on one end that prevents them from slipping through their insertion hole. They also have a small hole (or series of holes) drilled into the bottom, as clevis pins often work in conjunction with other types of pins that help them remain in place.

5. Wire Lock Pins

wire lock pin

Wire lock pins are designed with a hearty “wire” attached to the head of the pin that curves over the body in a spring-like mechanism and loops around the end to hold it in place.

6. Hitch Pins

hitch pin

This type of pin is often used in conjunction with other pins. Hitch pins come in many different sizes, and many are big enough to tow large vehicles. They have a handle at the top for easier grabbing and usually feature a hole in the body where another pin can be inserted to keep the hitch pin from falling out.

7. Spring Pins

roll pin

All pins mentioned so far generally leave a lot of room for movement — not the spring pin. Also called a roll pin, this type of pin acts as a spring, contracting upon insertion, pushing outward and ultimately locking into place.

8. Dowels

cylinder head dowel Powerstroke diesel

Like spring pins, dowels are meant for a snug fit. They’re used in automotive and furniture assembly to center and couple two components.

All pins are not created equal, but each has a special application and a unique time to shine. When you’re using pins, be sure to follow the manufacturer recommendations and best practices, and always replace like with like when you install new pins.

Check out all the pin products available on NAPA Online, or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on types of pins, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Blair Lampe.

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Blair Lampe View All

Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter.  In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.

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