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Tightening Key
A tightening key is a small wedge or shim used in the construction of a canvas stretcher frame with expandable joints. The key is inserted into the slotted inside the stretcher bars at the mitered corners of the frame to prevent or adjust sagging. Tightening keys are commonly made in plastic or wood, and are often called corner keys or corner wedges. Tightening keys were introduced in the mid-18th century, making expandable (versus rigid) stretcher frames possible. Use Most stretcher frames have eight keys, two in each corner. Each key is tapped in to expand the stretcher bars slightly, tensioning the canvas. The keys can be used to re-tighten the canvas as it relaxes naturally over time. If the key is tapped too forcefully, it may tear the side of the canvas. Conversely, keys that become too loose can fall out during handling and damage the painting's surface. The process of inserting keys into the stretcher is called "keying-out." Types Corner keys or wedges come in various for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stretcher Bar Corner With Keys
A stretcher, gurney, litter, or pram is an apparatus used for moving patients who require medical care. A basic type (cot or litter) must be carried by two or more people. A wheeled stretcher (known as a gurney, trolley, bed or cart) is often equipped with variable height frames, wheels, tracks, or skids. Stretchers are primarily used in acute out-of-hospital care situations by emergency medical services (EMS), military, and search and rescue personnel. In medical forensics the right arm of a corpse is left hanging off the stretcher to let paramedics know it is not a wounded patient. They are also used to hold prisoners during lethal injections in the United States. History An early stretcher, likely made of wicker over a frame, appears in a manuscript from . Simple stretchers were common with militaries right through the middle of the 20th century. Gurney Generally spelled ''gurney'', but also ''guerney'' or ''girney''. The first usage of the term for a wheeled stretcher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wedge (mechanical Device)
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 converting a force applied to its blunt end into forces perpendicular (normal) to its inclined surfaces. The mechanical advantage of a wedge is given by the ratio of the length of its slope to its width..''McGraw-Hill Concise Encyclopedia of Science & Technology'', Third Ed., Sybil P. Parker, ed., McGraw-Hill, Inc., 1992, p. 2041. Although a short wedge with a wide angle may do a job faster, it requires more force than a long wedge with a narrow angle. The force is applied on a flat, broad surface. This energy is transported to the pointy, sharp end of the wedge, hence the force is transported. The wedge simply transports energy in the form of friction and collects it to the pointy end, consequently breaking the item. History Wedges have exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shim (spacer)
A shim is a thin and often tapered or wedged piece of material, used to fill small gaps or spaces between objects. Shims are typically used in order to support, adjust for better fit, or provide a level surface. Shims may also be used as spacers to fill gaps between parts subject to wear. Materials Many materials make suitable shim stock (also often styled shimstock), or base material, depending on the context: wood, stone, plastic, metal, or even paper (e.g., when used under a table leg to level the table surface). High quality shim stock can be bought commercially, for example as laminated shims, but shims are often created ad hoc from whatever material is immediately available. Laminated shim stock is stacked foil that can be peeled off one layer at a time to adjust the thickness of the shim. Applications In automobiles, shims are commonly used to adjust the clearance or space between two parts. For example, shims are inserted into or under bucket tappets to control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canvas
Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags, electronic device cases, and shoes. It is popularly used by artists as a painting surface, typically stretched across a wooden frame. Modern canvas is usually made of cotton or linen, or sometimes polyvinyl chloride (PVC), although historically it was made from hemp. It differs from other heavy cotton fabrics, such as denim, in being plain weave rather than twill weave. Canvas comes in two basic types: plain and duck. The threads in duck canvas are more tightly woven. The term ''duck'' comes from the Dutch word for cloth, ''doek''. In the United States, canvas is classified in two ways: by weight (ounces per square yard) and by a graded number system. The numbers run in reverse of the weight so a number 10 canvas is lighter than number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stretcher Bar
A stretcher bar is used to construct a wooden stretcher used by artists to mount their canvases. They are traditionally a wooden framework support on which an artist fastens a piece of canvas. They are also used for small-scale embroidery to provide steady tension, affixing the edges of the fabric with push-pins or a staple gun before beginning to sew, and then removing it from the stretcher when the work is complete. Stretchers are usually in the shape of a rectangle, although shaped canvases are also possible. Construction Since a stretcher is simply a frame, it can be constructed in a variety of ways. The differences in construction have to do with how the corners are built. Commercially available pre-fabricated stretchers come in segments with interlocking corners, that can be fit together like puzzle pieces. Corner supports can also be made using simple woodworking techniques, however. In the case of the French stretcher, a mitre joint is used to adhere the corners. "Keys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miter Joint
A mitre joint (often miter in American English) is a joint made by cutting each of two parts to be joined, across the main surface, usually at a 45° angle, to form a corner, usually to form a 90° angle, though it can comprise any angle greater than 0 degrees. It is called beveling when the angled cut is done on the side, although the resulting joint is still a mitre joint. For woodworking, a disadvantage of a mitre joint is its weakness, but it can be strengthened with a spline (a thin wafer of wood inserted into a slot, usually arranged with the long grain of the spline across the short grain of the frame timber). There are two common variations of a splined mitre joint, one where the spline is long and runs the length of the mating surfaces and another where the spline is perpendicular to the joined edges. Common applications include picture frames, pipes, and molding. Non-perpendicular joints For mitre joints occurring at angles other than 90°, for materials of the sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. 9.2 billion tonnes of plastic are estimated to have been made between 1950 and 2017. More than half this plastic has been produced since 2004. In 2020, 400 million tonnes of plastic were produced. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will reach over 1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or woodchips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the productio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
18th Century
The 18th century lasted from January 1, 1701 ( MDCCI) to December 31, 1800 ( MDCCC). During the 18th century, elements of Enlightenment thinking culminated in the American, French, and Haitian Revolutions. During the century, slave trading and human trafficking expanded across the shores of the Atlantic, while declining in Russia, China, and Korea. Revolutions began to challenge the legitimacy of monarchical and aristocratic power structures, including the structures and beliefs that supported slavery. The Industrial Revolution began during mid-century, leading to radical changes in human society and the Natural environment, environment. Western historians have occasionally defined the 18th century otherwise for the purposes of their work. For example, the "short" 18th century may be defined as 1715–1789, denoting the period of time between the death of Louis XIV, Louis XIV of France and the start of the French Revolution, with an emphasis on directly interconnected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picture Framing
A picture frame is a protective and decorative edging for a picture, such as a painting or photograph. It makes displaying the work safer and easier and both sets the picture apart from its surroundings and aesthetically integrates it with them. Construction A picture frame is a container that borders the perimeter of a picture, and is used for the protection, display, and visual appreciation of objects and imagery such as photographs, canvas paintings, drawings and prints, posters, mirrors, shadow box memorabilia, and textiles. Traditionally picture frames have been made of wood, and it remains very popular because wood frames can provide strength, be shaped in a broad range of profiles, and allow a variety of surface treatments. Other materials include metals, e.g. silver, bronze, aluminum, and stiff plastics such as polystyrene. A frame surface may be of any color or texture. Both genuine gilding and imitation gold remain popular, although many other surfaces are to be found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
