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Last updated: November 20, 2020

What Is A Speed Square Used For?

By Herbert Dorman

You may be really wondering what a speed square is used for, more so if you have no idea about what it is. For those who are into DIY activities and things to do with construction will probably have an idea of what a speed square is. A speed square is an essential tool in most home and workshop projects as a carpenter, especially if you need to achieve fully accurate results. Knowing what is a speed square used for is important for the outcome increase.

Furthermore, it is important to really understand what a speed square can do for you, together with the markings on it. Without this knowledge, then it will be futile to invest in one. It has several uses and is not limited to determining the 45 and 90 degrees marking when cutting material such as wood or metal. This article gives you some insight into the speed square and its uses.


What Is A Speed Square Used For?

What Is A Speed Square Used For

We first need to know what a speed square is. A speed square is a marking out tool that is triangular and is mostly used by carpenters to ensure accurate results. There are other names that one can use to refer to this tool such as triangle square, rafter angle square or rafter square. So, in case you meet these names somewhere, they basically refer to the same thing. Notably, it has been in existence since time immemorial. 

It may either have plastic, steel or aluminum material on its construction. Besides, it is a quite common tool for carpenters, and you may not miss it in their toolbox. It can effectively perform the functions of a framing square, try square or combination square all at once. This makes it convenient for carpentry jobs and DIY projects.

Furthermore, it has some unique features that make it work the way it does. There is a cut that is in the shape of diamond around its edge that helps you to create a line that is perfectly 90 degrees during scribing. Other features include a fence that is lipped, numbers which are deeply engraved, cut outs and notches. All these play a good role in ensuring that it delivers excellent output altogether.

Additionally, there are wordings on the speed square that one needs to clearly familiarize with. There is the degree that outline the degrees ranging from 0 to 90. Common is basically used to show the increase that occurs over a 12-inch common rafter that is between inches 1 to 30. Lastly, the Hip/Val depicts how many inches the speed square can rise over a valley or hip rafter which is 17 inches. Also, there is a hypotenuse that lays out the degrees of the tool.


Uses Of A Speed Square


  • Acts as a guide for the saw

If you are using a circular saw to cut across a piece of wood, then you must consider a speed square to garner excellent and accurate results. You can be able to attain precise 45- and 90-degree angle cuts if guided by a speed square. Ensure that the fence of whatever you are working on holds securely to the boards using C-clamps that are medium in size. Thereafter, you can glide your circular saw in opposition to the speed square and finally cut the lumber.

The speed square is suitable for use as a saw guide because it is thicker as compared to a combination or a framing square. This ensures that the saw does not slide against the speed square hence accuracy. Besides, it makes sure you are safe when working on your lumber. To avoid any regrettable mistakes, you can carry out a few practices till you are satisfied that you are good to go.


  • Scribing Lines

When making a rip cut on your lumber, you will need to come up with an accurate guideline to obtain good results. This is where the speed square comes in. The lip of the speed square needs to be on the lumber’s outer edge while the tip of your pencil fits in any of the notches and begin scribing. It is that simple! The lipped edge ensures to give precise angles of 45 and 90 degrees thus giving you an easy time during scribing.


  • Pitching your roof

If you plan on replacing your roof or want to add any other thing to it, you will need to determine the angle of pitch of your roof. A speed square will effectively give you a simple solution to this if it comes with a level. The first thing to do is aligning the edge of your roof together with the lip of the speed square and ensure there is a torpedo level on its top. Achieving a center level confirms that you can easily tell the pitch angle of your roof.


  • Protracting purposes

Protracting basically involves reading angles and thereafter marking them to be useful for your work later. Because of the degree markings on the edge of the speed square, it becomes easy to protract. If you need to mark an angle of 60 degrees, ensure to place the pivot point firmly in opposition with the board that you are working on. Finish by drawing a line across the square found on the diagonal edge’s opposite side and then make the cut.


What you need to know before purchasing a speed square


Type of material

It is important to buy a speed square that has a heavy metal, steel or aluminum construction. These materials ensure the durability of your tool, hence lengthening its lifespan. Moreover, there are those that feature plastic construction, especially ones used for marking. Plastic material is friendly to your hands.



A good speed square is one which is lightweight and easy to carry from one point of the workshop to another with much ease. Most metal squares are heavier than plastic ones, but it all depends on what you plan to use your speed square for.


Final Verdict

Finding out what is a speed square used for is the main purpose of putting together this article. If you are a carpenter, then you cannot fail to use this tool in your day to day activities. It effectively puts together various functions in one simplified tool. Investing in this tool, makes your work easier and more convenient. Whether you want to mark or read angles, scribing lines or acting as a saw guide, this is a must have.