Types of pins! Holding it all together

All about different types of pins.

They’re little, they’re kooky, and they’re all over the dang place. It’s the ‘Pin’ and you may be surprised at how many you might encounter.


cotter pin

A cotter pin resembles a bobby pin on steroids. The cotter pin is inserted through two holes on one end of a clevis pin, then the ends are split apart to prevent the pin from sliding back out. There are several different thicknesses, and you want to make sure to replace any cotter pins with the same size pin.


shear pin

When we talk about “torque”, what were really talking about is movement and force. When two parts are connected to each other; one moving the other- the possibility of one of those parts suddenly becoming immovable is very real. And when that happens, the usual outcome involves something breaking! The shear pin is the guy that steps up and takes one for the team. A shear pin is designed to break before the bigger, more expensive parts do. Because shear pins are rated to break under a certain amount of pressure, it’s very important to replace a broken shear pin with the same pin. Putting in a thicker, tougher pin may result in something much more expensive breaking the next time around.



You have one part sitting inside of another part and something’s gotta keep them aligned to each other. Enter the spring pin. A spring pin (also called tension pin or roll pin) is a tiny little hardened steel ‘tube’ with a slot cut along the length of it and tapered ends. The correct spring pin should have a slightly larger diameter than the hole it’s going into, but it’s springy! So when the pin slides into the hole, it’s going to fit in there nice and tight so it won’t slide back out. They’re handy when you want to secure two parts together, but you don’t have the room for anything to protrude, or you simply don’t want to see the connector.


clevis pin

In the image above, we see an example of a “clevis fastener”. The Clevis fastener consists of the clevis (which is the ‘U’ shaped bracket), the Clevis pin (which is the part resembling an un-threaded bolt with a hole through the end) and a cotter pin.


linch pin

A linchpin is a fastener used to prevent a wheel or other part from sliding off the axle upon which it is riding. The pin itself is inserted through holes in the axle (or rod). Once inserted, the ring (which spring pivots at the attachment) is pushed over the end of the rod; securing itself against the pin.

Looks like the “pin” is mightier than the…well, no. A sword is still mightier than a cotter pin. But they’re special in their own way.

And that’s a little bit about the fastener pins you will no doubt run into on your lawn care equipment.

Do you have any questions or comments about the different types of pins?  Please feel free to contact us via phone, email or the comments section below.


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Bill Brown

Bill is the head of content creation for the LawnMowerPros Blog and DIY section. He’s been in the Outdoor Power Equipment Industry for years and he’s still learning new things everyday. You can often find him creating featured articles, DIY guides, videos, graphics and much more.