Other names |
|
---|---|
Classification |
|
Inventor | Laroy S. Starrett (1877) |
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. [1] [2] Other names for the tool include adjustable square, combo square, and sliding square.
The most common head is the standard head, which is used as a square for marking and testing 90° and 45° angles. [3] The other common types of head are the protractor head, and the centre finder head. [4]
Combination square rules are made of steel and can be purchased with gradations in metric, imperial, or both metric and imperial. Both faces of the rule have markings, providing four different sets of markings. This allows different sides to have different graduations (eg. 1mm or 0.5mm markings) or units (ie. metric and imperial). The rule typically comes in lengths between 150mm and 600mm or between 4 inches and 24 inches. [1] [2]
The heads, occasionally called anvils, are attached to the rule by sliding the rule into a slot in the side of the head. The head is then tightened in place via a lock bolt or lock nut which engages with a channel running the full length of the rule, allowing the head to be tightened on at any point along the rule. [4] [2]
The standard or square head has three adjacent flat faces, two of them meet square to one another, and the third face is angled away at 45°. When attached one face is parallel to the rule, one face is perpendicular, and one face is at 45°. The standard head usually incorporates a small spirit level and a small removable scriber. [4]
The protractor head has a flat reference edge which is attached to an adjustable 180° protractor or (sometimes called a turret) with a graduated scale in both directions for reading both the angle or the complement angle. [1] The protractor head sometimes includes a small spirit level. [4] [2]
The centre finder head has two faces meeting at 90°, when attached one edge of the rule bisects the two faces at 45°.
The heads are manufactured from either forged steel, cast iron, die-cast aluminium, die-cast zinc, or plastic. Aluminium and zinc heads are cheaper than steel and iron, but less durable and more prone to inaccuracy. [5] Cast iron and steel heads are also notably heavier. The heads are usually painted except for the flat machined reference faces.[ citation needed ]
As well as being used as a regular standalone rule or straightedge, the rule is used in combination with the different heads.
The standard head can be used as a:
The protractor head can be used for:
The centre finder head can be used for:
Though some earlier 19th century tools were called combination squares, the modern combination square was invented in the late 1870s by American inventor Laroy S. Starrett, and patented in 1879. [note 1] [8] In 1880 he founded the L. S. Starrett Company in Athol, Massachusetts, United States. The tool was originally designed for machinists, but over time became commonly used in other trades, such as woodworking. [7]
A ruler, sometimes called a rule, line gauge, is an instrument used to make length measurements, whereby a user estimates a length by reading from a series of markings called "rules" along an edge of the device. Commonly the instrument is rigid and the edge itself is a straightedge, which additionally allows one to draw straight lines. Some rulers, such as cloth or paper tape measures, are non-rigid. Specialty rulers exist that have flexible edges that retain a chosen shape; these find use in sewing, arts, and crafts.
A spirit level, bubble level, or simply a level, is an instrument designed to indicate whether a surface is horizontal (level) or vertical (plumb). Two basic designs exist: tubular and bull's eye . Different types of spirit levels may be used by carpenters, stonemasons, bricklayers, other building trades workers, surveyors, millwrights and other metalworkers, and in some photographic or videographic work.
A hand plane is a tool for shaping wood using muscle power to force the cutting blade over the wood surface. Some rotary power planers are motorized power tools used for the same types of larger tasks, but are unsuitable for fine-scale planing, where a miniature hand plane is used.
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 types of square, the try square is considered one of the essential tools for woodworking.
A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, γωνία (gōnía) 'angle' and μέτρον (métron) 'measure'. The protractor is a commonly used type in the fields of mechanics, engineering, and geometry.
The steel square is a tool used in carpentry. Carpenters use various tools to lay out structures that are square, 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. It consists of a long, wider arm and a shorter, narrower arm, which meet at an angle of 90 degrees. 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 ; they can also be made of aluminum or polymers, which are light and resistant to rust.
Caliper(s) or calliper(s) are an instrument used to measure the dimensions of an object; namely, the diameter or depth of a hole. The least count of vernier caliper is 0.1mm
A machinist square or engineer's square is the metalworkers' equivalent of a try square. It consists of a steel blade inserted and either welded or pinned into a heavier body at an angle of 90°. Usually a small notch is present at the inside corner of the square. This prevents small particles from accumulating at the juncture and affecting the square's reading.
In various contexts of science, technology, and manufacturing, an indicator is any of various instruments used to accurately measure small distances and angles, and amplify them to make them more obvious. The name comes from the concept of indicating to the user that which their naked eye cannot discern; such as the presence, or exact quantity, of some small distance.
A sine bar consists of a hardened, precision ground body with two precision ground cylinders fixed at the ends. The distance between the centers of the cylinders is precisely controlled, and the top of the bar is parallel to a line through the centers of the two rollers. The dimension between the two rollers is chosen to be a whole number and forms the hypotenuse of a triangle when in use.
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 setup is designed to remove the need to mark out every individual piece.
Japanese carpentry was developed more than a millennium ago through Chinese architectural influences from the 12th century. It is a form of ancient Chinese wooden architecture and woodworking joints that involves building wooden furniture without the use of nails, screws, glue, or electric tools.
A marking gauge, also known as a scratch gauge, is used in woodworking and metalworking to mark out lines for cutting or other operations. The purpose of the gauge is to scribe a line parallel to a reference edge or surface. It is used in joinery and sheetmetal operations.
A wiggler, also known as a wobbler, edge-finder, center-finder or laser-centering-device, is a tool used with a machine like a mill, to accurately align the machine head with the work prior to machining.
A drafting machine is a tool used in technical drawing, consisting of a pair of scales mounted to form a right angle on an articulated protractor head that allows an angular rotation.
A speed square, also called a rafter square, rafter angle square, and triangle square, is a multi-purpose triangular carpenters' tool used for marking out. Its functions include many of those of a combination square, try square, and framing square. Carpenters use it to make basic measurements and mark lines on dimensional lumber, and as a saw guide for short 45 and 90 degree cuts.
A square is a tool used for marking and referencing a 90° angle, though mitre squares are used for 45° angles. Squares see common use in woodworking, metalworking, construction and technical drawing. Some squares incorporate a scale for measuring distances or for calculating angles.
A miter square or mitre square is a hand tool used in woodworking and metalworking for marking and checking angles other than 90°. Most miter squares are for marking and checking 45° angles and its supplementary angle, 135°.