Rafter square, speed square, triangle square, and rafter angle square are actually the same tools in spite of their different names.
This tool is used for a range of applications such as measuring, layout, marking, and scribing guide, it acts as a saw guide for 90- and 45-degree cuts, establishes perpendicular angles, and makes rafters. We can use it to establish a vertical reference for plumb as well.
In terms of the name rafter square, it actually comes from the specific application of this speed square, that is to help make rafter.
On the other, the name speed square is actually based on the original model from Swanson (Swanson Speed Square). The idea behind this square is to make a work-saving tool. But, it becomes a general name for this triangle tool. And up til now, people still call this triangle square as speed square.
What is Rafter Actually?
A rafter is a structural component in the shape of a beam that has some slope and supports the roof. It is part of the frame that holds the roof, they are designed to strengthen the roof deck against the load.
Rafters are used because they are easy to construct and easy to install. Rafters are laid side by side, parallel to each other. The purpose of the rafter is to support the structure and distribute the load, so its application is not limited to only roofs but also sheds and other outbuildings.
One disadvantage of rafters against trusses is that they need a long procedure because they need to be cut in the right size on-site while trusses are built in bulk.
How Speed Square Benefits You in Making the Rafter
Rafters are a key part of the frame and require accurate measurements and cut to distribute weight evenly and keep the structure standing. To make a rafter you first have to take all the measurements and perform all calculations and then determine the dimensions, pitch, rafter length, and the number of rafters required.
The hypotenuse side of the speed square has angle markings starting from zero to ninety degrees which enables you to cut the rafter in accordance with the slope. The speed square has two angle guides inside the tool. They are marked as “hip-valley” angles and common rafter angles.
To mark the plumb cut, put the pivot point of speed square on the top edge of the rafter board. Move the speed square until the rectangular slot is at the right pitch on top of the board. Use the common top cut table which will make an angle for the plumb cut at the end of the board. Rafter table that comes with the rafter square, make proper use of them e.g., to define the rafter length.
In short, speed square has got all the attributes required to accomplish the job (rafter making) accurately and efficiently. But this is not the only tool that assures this work, framing square is on par with the speed square to ensure good results. To read more and know which one handles the job better, the key attributes and functions are compared in the article “The Difference Between Framing Square and Speed Square“.