There are numerous building codes to which staircases must conform. Laying out a staircase requires rudimentary math. There are many types of stairs: open, closed, fully housed, winding, and so on, to mention a few of them. The stringer is the structural member that carries the load of the staircase, the tread is the horizontal part that is stepped on, and the riser board is the vertical part which runs the width of the structure. They are the stringer, the tread and the riser. Stairs usually consist of three components. Theoretical rise and run of stringer, placement of square, marking of tread and rise, dropping the stringer, ABC=90°, total rise of stringer = 2R-T, total run of stringer = 2AB. The error can be corrected by opening or closing the angle with a center punch. This allowed for quick layouts of mortise and tenon joints when working both hard and softwoods.Ī steel square is self-proving and self-calibrating in that you can lay out a perpendicular line, flip the square over, and determine the size and direction of the error. Likewise, mortises and tenons were traditionally one and a half inches (38 mm) wide when working in hardwoods, explaining the width of the tongue. In traditional timber frame joinery, mortises and tenons were typically two inches (51 mm) wide and two inches (51 mm) from the edge of the timber when working with softwoods, giving rise to the width of the blade. On the newer framing squares there are degree conversions for different pitches and fractional equivalents.įraming squares may also be used as winding sticks. It has a diagonal scale, board foot scale and an octagonal scale. The square has many uses, including laying out common rafters, hip rafters and stairs. The longer wider arm is two inches (51 mm) wide, and is called the blade the shorter narrower arm, is one and a half inches (38 mm) wide, and is called the tongue. Today the steel square is more commonly referred to as the framing square or carpenter's square, and such squares are no longer invariably made of steel (as they were many decades ago) they can also be made of aluminum or polymers, which are light and resistant to rust. It consists of a long, wider arm and a shorter, narrower arm, which meet at an angle of 90 degrees (a right angle). Carpenters use various tools to lay out structures that are square (that is, built at accurately measured right angles), many of which are made of steel, but the name steel square refers to a specific long-armed square that has additional uses for measurement, especially of various angles. The steel square is a tool used in carpentry.
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