# Double Square Vs. Combination Square

In woodworking, to measure the dimensions of different parts which are to be crafted or joined together, different tools are used. To check of the two meeting surfaces whether they are perpendicular to each other, squares are used. These square tools commonly consist of two blades that are fixed perpendicular to each other.

The angle of 90 degrees can be observed in almost every object, so it is important to get it right. To make sure these different types of squares are used which have their perks. The difference in working and properties of double and combination squares is discussed here.

Double Square

Double square is usually used in woodworking and machining to measure square angles. The main attribute of the double square is that it can measure perpendicular angles in multiple of two or from both sides. Double squares are available in different sizes but four, six, and twelve inches are most common.

1. Structure

The main components of this tool are the blade and rule. The rule is made of a durable material and has markings on it for measurement. There is a groove in the rule in which stock sits and slides easily.

2. Working

The reason that it can be used for two side measurement is its sliding blade allows the movement to either side and since both sides are flat there is a need to invert the square.

In comparison to a combination square, the advantage of a double square is that you can use it in tight places where a combination square will not fit. It not only assures the 90 degrees angle of meeting surfaces but also is easy to set up for markings and cuts because both sides are flat.

It is not much of a disadvantage, but the double square has a limitation that only allows you to measure right angles. You cannot measure any other angle except 90 degrees.

Combination Square

A combination square is a marking and measuring tool that is used in metal and woodworking to reference and check if the surfaces are flat and perpendicular to each other. The key difference in combination square is that it can measure the 45-degree angle in addition to 90-degree angles.

1. Structure

When comparing the structure of combination square and double square, we will find them almost similar. A combination square consists of a ruler and a blade. A rule is made of durable material such as steel and has graduation in imperial, metric, or both units. Another similarity to the double square is the handle can be adjusted back and forth by using the adjustable knob.

The big difference in structure lies in the handle. The handle structure provides some features of a spirit level vial that can be used to determine the level of the surface being checked.

Aside from that, the combination square can provide other attachable features such as protractor and center finder. While the standard model only ensures two angles (90-and-45-degree angle), the protractor head can be set to any angle.

2. Working

Working of a combination square is almost the same as a double square. When adjusting the handle, it slides along the built-in grove in the rule. It’s also easily removable to use combination square as a simple rule.

A combination square can check both inside and outside 90-degree angles. However, you cannot quickly check those inside and outside angles. You need to slide the handle. So, it’s a little trickier to check inside and outside 90-degree angle at the same time.