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Lag Bolts vs Carriage Bolts

Pulished on May. 05, 2023

Carriage bolts are just a common fastener used in many different large-scale construction projects. For DIY homeowners, the options are almost endless when it comes to different kinds of screws, bolts, and other fasteners to use in their projects. Sometimes, several different types of fasteners are required in decks, children's play areas, sheds, docks, and other similar projects. Here are some ways to identify when to use which type.

Carriage Bolts

Carriage Bolts

Everyone has their own job

The important thing to remember when dealing with different types of fasteners is that they have their own functions. This means that a deck screw will not be enough to post drywall. When it comes to carriage bolts and lag bolts, people often confuse or classify them as the same thing. However, they are different in many ways.


Compared with lag bolts, carriage bolts are more like bolts. The carriage bolt is a straight barrel with flat edges. It has a small square neck at the top, and when it is fixed in place, it will not rotate. This means you must countersink the bolt, and it performs as it should. On the other hand, lag bolts have a point and wide thread at the end and are used in wooden structures.

Use of carriage bolts

It is important to remember the differences in the construction of the two different bolts. If you can remember this, then you can better distinguish what each bolt can be used for. Because the ends of the carriage bolts are flat, you will need to use a washer and a nut to complete the fastening.

Relatively speaking, carriage bolts are very powerful. Once installed, they can bear huge weight. Let us consider a grade 5 carriage bolt. They can withstand a force of 8,437 kilograms per square meter. Moreover, their tested weight is 5976 kg!

Pergola structure: When two pieces of wood are adjacent, you can use a carriage bolt if you drill completely through them. Then insert the carriage bolts into the holes and fix them with washers and nuts.

Docks: There are many places on the dock that require carriage bolts. Frames and tracks are just two examples.

Children's swing: One of the main uses of a carriage bolt is in the construction of children's play areas or swing sets.

The use of lag bolts

With the tip of the lag bolt, you can screw them directly into the wood without having to make a hole. This means that when you need extra strength during construction, you usually use lag bolts.

Decks: When connecting the classification board of the deck to a home, lag bolts are the best choice because they are screwed directly to the bolts.

Rafters: Building a shed, garage, or other outbuildings that requires screws to a larger foundation will require a lag bolt.

You can use this new knowledge for your next project.

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