Types of Square Tools

Square tools are easy to find in the workshop whether it is a machinist or woodworking workshop. It functions mainly to check the squareness, perpendicularity, and right angle (90-degree angles). Nowadays, squares are used for marking, scribing, framing, drawing, etc. That’s because the square helps scribe lines either perpendicular or parallel to the edge of the object being scribed.

If you are going to buy a square, it’s better to know that there are several types of square tools out there that are used in woodworking, carpentry, and machining. These different squares may confuse you but drive you to the right tool to choose from.

Square Tool or Perpendicular Tool?

The term “square tool” is actually not an appropriate term in our opinion because many square tools don’t come in a square shape, instead, they come in only 2 or 3 sides. They should be called a perpendicular tool.

Body Parts

The most important body parts of the square tool are the straight edge and 90-degree angle edge. However, since they come in several different models, the other body parts appear such as the head, level vial, 45-degree angle edge, degree mark, scale, graduation, etc.

The body can be made from several materials. Some of them are a piece of material while the others are containing more than one material. Speed square, for example, is made of a certain aluminum material while try square can be made of wood and metal. It’s also not weird that a square tool is made from stainless steel or hardened steel to enhance durability.

1. Machinist Square

Among the other types of square tools, the machinist square or engineer square is designed for high-precision jobs. It’s only off several micrometers per several hundred millimeters. According to DIN 875, the lowest grade of machinist square (Grade 2) must be off at/lower than 30 μm per 100 mm. While woodworking square tolerance is not that tight.

Because of that accuracy, the machinist square is applicable to calibrate other lower accurate squares such as the try square, combination square, double square, framing square, T square, and speed square; most of the square tools that we are discussing here.

In terms of material construction, its handle and blade are made of the same hard metal. Besides, they are usually one body construction to retain their accuracy. If you work mostly with squares, then having a machinist square is a must to inspect your squares regularly.

To work with a machinist square to calibrate square tools, you should use it with a surface plate. In addition to checking for squareness, another precision standard that you can use is a cylindrical square.

2. Try Square

Try square is one of types of square tools
Using try square to scribe a perpendicular line

Like machinist square, try square has an L-shape construction. But, try square is not as accurate as the machinist square. The blade and handle are not one body. The conjunction of several screws may be applied to this square. It’s easy to find try square’s handle and blade come in different materials. Try square’s handle can be made of metal, wood, aluminum, or plastic while its blade is metal, wood, or plastic.

It’s used to check squareness, scribe perpendicular lines to the edge of a certain surface, mark lines or dots, and measure length. One of the biggest advantages of a try square for squareness checking is that you can use it to check both inside and outside squareness. Besides, its price is affordable and pretty durable. So for some applications such as woodworking and carpentry, try square is appropriate to use.

There are several models of try square on the market. From the simple one with no graduations at all (the classic model with wood head) to the current models (which employs hole guides for easy and accurate scribing, spirit level, angle marking, adjustable blade angle degree, etc), all is available to choose from to match with your needs.

Check out our top 10 picks of try squares here.

3. Double Square

Double square is one of types of square toolsDouble square is almost similar to a try square. The difference lies in the head/handle/stock that can move along the blade. After sliding the head for a little adjustment, you can tighten it back. So, it’s pretty flexible in some applications.

It’s also similar to combination square which can slide as well. However, it doesn’t have miter square integrated in it. A double square also lacks of level vial to check the surface levelness.

For the functions, like many other square tools, it allows you to check right and left angles. In some cases, it can be a depth gauge, especially if the blade width is small. Woodworkers and carpenters benefit immensely from this tool because it excels to use in tight space. The current double squares on the market that we can find are available in 4″ and 6″ blade lengths.

4. Mitre Square

mitre square

A mitre square has the job to check 45-degree angles. It’s better to buy a combination square if you need a mitre square for you project. The combination square has a built-in mitre square which means saving money.

5. Combination Square

Combination square (near protractor) and other measuring tools
Combination square (near half circle protractor with single long arm) and other measuring tools

The combination of double square, mitre square, and center finder forms a new hybrid square tool called a combination square, as the name suggests. Aside from that, this model also usually comes with a spirit level for level checking. Some models also come with a protractor attached to the blade that allows you to measure the object corner.

It can check outside and inside squareness, check levelness, measure angle, find the center dot of a circle object, etc. Other functions such as depth gauge can be performed by a combo square as well. If the blade is manufactured with high quality, it can be your straightedge as well.

One brand that produces combination squares with a lot of series is Starrett. It comes in different blade lengths, different blade material, graduation, finish, etc. Some series don’t come with the protractor and center finder. These options help you save money if you don’t need the protractor and center finder, meanwhile, getting the benefit from the core advantage of a combination square.

Combination square is widely used in masonry, woodworking, and also metalworking.

Read further: Top 10 Best Combination Squares

6. Speed Square or Rafter Square

Square tool is adjusting a blade
The speed square tool is adjusting a blade

The speed square or rafter angle square or pivot square is a triangle square tool. You can quickly check the 45° and 90° angles of the object’s internal corner with it. Besides, it can be a protractor as well. Some people use it as a saw guide. People can also use speed square with plumb bob to check the plumb or to establish the vertical line reference. Perhaps, it’s the reason where the name speed square comes from.

Unlike the other squares, the body shape of this tool is a triangle. You could see some holes, graduations, angle markings, and line scribing guide holes on the body. If you are looking for the best speed square for your need, don’t forget to consider the holes so that your scribing is easy and accurate. In terms of shape, one of its sides has a T-shape area. It helps you place this tool exactly at the edge of an object being marked so that it doesn’t easily slide.

Many jobs benefit from this tool including woodworkers, machinists, and carpenters.

7. Framing Square

Framing square is one of types of square tools and used primarily in carpentry
Framing square (black), tape measure, hammer, and a pair of gloves

Like machinist square and try square, the shape of the framing square is like an L. The longest straight part is the blade while the shortest part is the tongue.

It’s made from steel or aluminum. If it’s made from steel, a reinforcement to prevent corrosion and rust is required. On the other hand, if it’s made from aluminum, commonly it’s anodized aluminum which is better to fight against rust and abrasion. We also find it made from stainless steel. The stainless steel framing square is heavy, solid, and corrosion-resistant.

Although the primary function of this tool is for layout tool, it can check inside and outside squareness as well. The blade can be straight edge as well if it has a high degree of straightness.

Mostly, the application of framing square is in carpentry such as in roofing, stairway, etc. Thus, it’s not weird it’s called carpenter square.

Due to its applications as the layout tool in carpentry, you can easily find the framing squares with its body surface containing rafter tables, scales, and other charts.

Read further: Top 12 Framing Square Reviews.

8. T Square

T Square with Plastic Head and Metal BodyThe last type of square tool that you have to know is T square. As the name tells, its shape is like a T.

Though a square, for squareness checking, it cannot check the internal side squareness, only the outside squareness.

However, most applications of T square are not for squareness or perpendicularity checking, but for marking. Due to its head that shapes a 90-degree corner to the blade, it helps mark the perpendicular line that goes from the edge of an object.

There are 54″, 48″, 32″, 24″, 18″, 12″, and 6″ T squares on the market. Your project determines the size that you need. The sizes of 54″, 49″, 32″ and 24″ are considered applicable for drywall cutting. The T square can quickly assist you, even with no need for marking, you can just use your knife because the blade can guide the knife. On contrary, the smaller sizes are suitable for architecture, technical drawing, and artisan.

The models of T squares also vary. Some models look like a ruler with guide holes. This model allows you not only to mark perpendicular lines, but also horizontal lines. We also find it with an adjustable blade. Special material for the head is important to consider when working with subtle material. That said, your T-square head should be made of plastic to prevent scratching the object surface.


Those are the 8 types of square tools you can find on the market. Although their main function is to check a certain angle, in fact, these square tools have been developed to cover other functions such as scribing and marking. Buying a square tool should go first by learning the different functions of each of them. Herewith, you can pick the best one for you.