A staircase jig is a woodworking tool that incorporates both a

right angle In geometry and trigonometry, a right angle is an angle of exactly 90 Degree (angle), degrees or radians corresponding to a quarter turn (geometry), turn. If a Line (mathematics)#Ray, ray is placed so that its endpoint is on a line and the ad ...

and an

acute 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 ...

in its design. The

jig The jig ( ga, port, gd, port-cruinn) is a form of lively folk dance in compound metre, as well as the accompanying dance tune. It is most associated with Irish music and dance. It first gained popularity in 16th-century Ireland and parts of ...

is easily transported due to its small size and light weight. Precise

measurements Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared t ...

are required to

layout Layout may refer to: * Page layout, the arrangement of visual elements on a page ** Comprehensive layout (comp), a proposed page layout presented by a designer to their client * Layout (computing), the process of calculating the position of obj ...

the

diagonal In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal. The word ''diagonal'' derives from the ancient Greek δ ...

locations. This jig uses a zero reference line from which the rise and tread are measured. The upper part of the jig is a

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 roundover overhang. The template allows for a tight fit of the tread into the stringer in the overhang section. The bottom of the jig incorporates an acute angle. This tapered angle allows a space for a

wedge A wedge is a triangular shaped tool, and is a portable inclined plane, and one of the six simple machines. It can be used to separate two objects or portions of an object, lift up an object, or hold an object in place. It functions by converti ...

to fit against the back side of the

vertical Vertical is a geometric term of location which may refer to: * Vertical direction, the direction aligned with the direction of the force of gravity, up or down * Vertical (angles), a pair of angles opposite each other, formed by two intersecting s ...

and the

horizontal plane In astronomy, geography, and related sciences and contexts, a '' direction'' or ''plane'' passing by a given point is said to be vertical if it contains the local gravity direction at that point. Conversely, a direction or plane is said to be hor ...

of the stringer. This jig can be used to lay out different rise (vertical) and tread (horizontal) widths. The jig is used with a plunge router and a bushing guide. The router plows out a precise groove into the finished product that allows all the parts to fit together.

Uses of jig

The jig is used to make finish

stringer Stringer may refer to: Structural elements * Stringer (aircraft), or longeron, a strip of wood or metal to which the skin of an aircraft is fastened * Stringer (slag), an inclusion, possibly leading to a defect, in cast metal * Stringer (stairs), ...

s, in interior staircase fabrication. The stringer is also referred to as a skirtboard. It can be used in a closed staircase or an open staircase where one side of the staircase is exposed and the other is housed into the skirtboard.

Design of jigs

The jig in the image is designed to cut only one segment of the stringer at a time. Some industrial staircase jigsFine woodworking, Tilt-Top Table, Mario Rodriquez, pg. 74, No. 173, 2004 are designed to cut out an entire stringer in one setup. There are jigs to cut dovetails, mortise & tenon joints, box joints, keyed miters, finger joints, bridle joints, scarf joints, and many other joints. All these jigs add precision, consistency, and productivity to a job.

References

{{Woodworking Woodworking jigs Construction equipment

Uses of jig

Design of jigs

See also

References