The most used tool in residential construction is the Swanson Speed Square. From laying the sill plates on the foundation wall to laying out rafter cuts and everything in between, the speed square is arguably the most important tool on a carpenters tool pouch.
The speed square is also a tool of convenience. It has replaced the cumbersome but reliable combination square as the carpenters choice. Its triangular shape makes it easy for the tradesman to keep on hand and in easy reach. Because of its shape, it can be kept in a tool pouch, on a hook on ones side, or even in your back pocket.
The speed square is packed with useful features and can be used for more than just squaring up lumber. Since its shape is a right triangle, one side is a 45 degree angle. This is convenient for quickly marking miters, 12/12 pitch rafters and anything else that might require that angle.
Another feature makes wall layout quicker. For instance, if your laying out a stud and cripple for a door or window, the speed square never has to leave the plate. Once the line is drawn for the stud location, there are marks on the inside of the square parallel to the plates edge from 1" to 3 1/2 inches in quarter inch increments, that can be used to measure over an 1 1/2" for the other side of the stud. This can be achieved by lining up the 1 1/2" mark on the previously drawn line and making a mark for the other side of the stud. Do this again and you've got an1 1 1/2" space for the cripple. By using the 3 1/2" mark one can layout the wall leads for wall intersections.
Along the edge used for squaring is a ruler. This has marks every 1/8th inch up to seven inches. Opposite the rule on the inside edge of the square, there are notches to put your pencil into to scribe lines parallel to the edge of your work. These notches are spaced at 1/4 inch, from 3/4" to 2 1/2". There is a diamond cutout at 3 1/2" for a scribe of 3 3/8", 3 1/2", and 3 5/8".
All these features are very useful but the main reason one would buy a speed square is for the rafter cut layout feature. Along the 45 degree angle edge there are marks for common rafters and hip and valley rafters for pitches 1 in 12 up to 30 in 12. Along the very edge are marks for degrees of angles. These marks start at 1 degree up to 90 degrees.
Along with the speed square a booklet is included with information on how to use the square, rafter tables to give you rafter lengths, and information on how to layout cuts for common, hip and valley rafters. The booklet alone is worth the price of the speed square.
If your doing any type of framing,the speed square is one tool you should not be without. The name says it all. It allows you to do many tasks quickly and accurately.
I almost forgot another use. I once saw a carpenter use his speed square to eat potato salad.
Mike Merisko (C) 2007