A Swanson Speed Square. A speed square, also called a rafter square, rafter angle square, and triangle square, is a multi-purpose

triangular A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices ''A'', ''B'', and ''C'' is denoted \triangle ABC. In Euclidean geometry, any three points, when non- collinea ...

carpenters' tool use for

marking out Marking out or layout means the process of transferring a design or pattern to a workpiece, as the first step in the manufacturing process. It is performed in many industries or hobbies although in the repetition industries the machine's initial set ...

. Its functions include many of those of a

combination square A combination square is a multi-purpose measuring and marking tool used in metalworking, woodworking, and stonemasonry. It is composed of a rule and one or more interchangeable heads that can be attached to the rule. Other names for the tool includ ...

try square A try square or try-square is a woodworking tool used for marking and checking 90° angles on pieces of wood. Though woodworkers use many different Square (tool), types of square, the try square is considered one of the essential tools for woodwor ...

, and framing square. Carpenters use it to make basic measurements and mark lines on

dimensional lumber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, wi ...

, and as a saw guide for short 45 and 90 degree cuts. The term "speed square" is a

genericised trademark A generic trademark, also known as a genericized trademark or proprietary eponym, is a trademark or brand name that, because of its popularity or significance, has become the generic term for, or synonymous with, a general class of products or ...

based on those owned by Swanson Tool Company which first manufactured and sold the tool.

History

Albert J. Swanson invented the A Speed Square in 1925 as a carpenter's layout tool. He later founded Swanson Tool Company to produce it. Today, Swanson Tool Company still manufactures and distributes the Speed Square and other carpentry tools from its headquarters in Frankfort, Illinois.

Design

Speed squares are manufactured from a variety of materials such as

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

, and composites such as

HDPE High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, ...

. They are also made in several sizes, including 7-inch, 8-inch, 25-cm and 12-inch sizes. Embedded degree gradations on the tool eliminate the need for

trigonometric Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. ...

calculations and allow for lines to be more easily made. The tool is an

isosceles In geometry, an isosceles triangle () is a triangle that has two sides of equal length. Sometimes it is specified as having ''exactly'' two sides of equal length, and sometimes as having ''at least'' two sides of equal length, the latter versio ...

right triangle A right triangle (American English) or right-angled triangle (British), or more formally an orthogonal triangle, formerly called a rectangled triangle ( grc, ὀρθόσγωνία, lit=upright angle), is a triangle in which one angle is a right an ...

with a ruler on one equal side and a

fence A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or netting. A fence differs from a wall in not having a solid foundation along its whole length. ...

on the other. It is marked with the word ''Pivot'' at the right angle point and displays ''Degrees'' on its

hypotenuse In geometry, a hypotenuse is the longest side of a right-angled triangle, the side opposite the right angle. The length of the hypotenuse can be found using the Pythagorean theorem, which states that the square of the length of the hypotenuse equa ...

, ''Common'' and ''Hip/Val'' markings on its midsection. *''Degree'' indicates the angle in degrees from 0° to 90°. *''Common'' indicates the rise in inches over a 12 inch run for common rafters from 1 inch to 30 inch. *''Hip/Val'' indicates the rise in inches over a 17 inch run for hip or valley rafters from 1 inch to 30 inch. Some models have divots for fitting a writing utensil to mark lumber with. Speed squares made by the Swanson Tool Company also have a diamond shape cutout on the ruler side at 3½ inches.

Usage

Among its basic uses are marking common,

hip In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint. The hip region is ...

, valley and hip, or valley jack rafters, laying out stair stringers, determining and marking angles, and making square cuts on boards. Common lines made using a speed square include perpendicular cut marks and

angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two ...

s for roofs, stairways, and decks. The tool uses a 0° reference. This means when a board is squared off the tool reads 0°. The angle derived is actually a

complementary angle In Euclidean geometry, an angle is the figure formed by two rays, called the '' sides'' of the angle, sharing a common endpoint, called the ''vertex'' of the angle. Angles formed by two rays lie in the plane that contains the rays. Angles ar ...

. For example a 22.5° angle is actually 67.5°. The sum of the angles equals 90 degrees (22.5° +67.5°= 90°). It is also obvious from a visual check that where the instruments displays 22.5° is not 22.5°. Many newer slide miters and miter boxes display both angles. Some of the new calculators have a 0° and a 90° references to do angular calculations. This can create confusion if the user does not understand this angular calibration. To find an angle such as 22.5°, hold the end of the square marked "pivot" against the board and rotate the square until the edge of the board lines up with appropriate number on the degree scale. Draw a line along the side of the square with the inches (pivot side) to indicate the angle for cutting. Use the "Common" scale to cut for Rise over Run.

References

External links

How to Use a Swanson Speed Square as a Framers SquareSPEED SQUARE MADE SIMPLE
(video) {{DEFAULTSORT:Speed Square Woodworking measuring instruments Dimensional instruments American inventions Squares (tool)

History

Design

Usage

See also

References

External links