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47-430: The kohte is assembled on-site from four identical panels of heavy canvas, almost always black, each formed by sewing two triangles together and cutting off the apex. The four panels together weigh approximately 10 kilograms (22 lb); separately, they can be carried to the campsite by several members of the group. The panels are fastened together using either a loop and grommet system or a loop-strap system, depending on

94-613: A camp kitchen or assembly tent. Still larger structures are possible using many panels. Eberhard Koebel , a leader in the German Youth Movement, developed the kohte with friends on the model of Sámi tents, wanting to reproduce their characteristic central roof hole, which made a fire inside the tent possible for winter camping. He gave it the name kohte based on the Swedish term for Sámi tents, kåta . The prototype, made in Stuttgart ,

141-420: A drying and softening operation, and may include splitting, shaving, dyeing , whitening or other methods. For some leathers, tanners apply a surface coating, called "finishing". Finishing operations can include oiling, brushing, buffing, coating, polishing, embossing, glazing , or tumbling , among others. Leather can be oiled to improve its water resistance. This currying process after tanning supplements

188-432: A flexible form that does not become putrid when rewetted. Many tanning methods and materials exist. The typical process sees tanners load the hides into a drum and immerse them in a tank that contains the tanning "liquor". The hides soak while the drum slowly rotates about its axis, and the tanning liquor slowly penetrates through the full thickness of the hide. Once the process achieves even penetration, workers slowly raise

235-623: A properly managed facility. A review of the total pollution load decrease achievable according to the United Nations Industrial Development Organization posts precise data on the abatement achievable through industrially proven low-waste advanced methods, while noting, "even though the chrome pollution load can be decreased by 94% on introducing advanced technologies, the minimum residual load 0.15 kg/t raw hide can still cause difficulties when using landfills and composting sludge from wastewater treatment on account of

282-482: A smoke hole, so a fire can be lit inside; in rainy weather, this is covered with a tarpaulin. Lean-tos and bivouac shelters sleeping one to three people can be made using one panel (a kröte , 'toad') or two (a locomotive ). A larger tent, the Jurte (' yurt ') is made using six kohte panels for the roof (six panels form a circle) and twelve rectangular panels to form a vertical side wall; it can sleep twenty or be used as

329-430: A variety of items, including clothing, footwear, handbags, furniture, tools and sports equipment, and lasts for decades. Leather making has been practiced for more than 7,000 years and the leading producers of leather today are China and India. Critics of tanneries claim that they engage in unsustainable practices that pose health hazards to the people and the environment near them. The leather manufacturing process

376-482: A variety of ways. They have been utilized as chest handles or on row boats as a soft oar lock. They are a rope ring that is made by first disassembling the rope then re-weaving the strands to the desired size. Holes in metal or another hard material will often have sharp edges. Electrical wires , cord , rope , lacings, or other soft vulnerable material passing through the hole can become abraded or cut, or electrical insulation may break due to repeated flexing at

423-628: A wet cloth or soaking the leather in water. Various treatments are available such as conditioners . Saddle soap is used for cleaning, conditioning, and softening leather. Leather shoes are widely conditioned with shoe polish . Due to its high resistance to abrasion and wind, leather found a use in rugged occupations. The enduring image of a cowboy in leather chaps gave way to the leather-jacketed and leather-helmeted aviator . When motorcycles were invented, some riders took to wearing heavy leather jackets to protect from road rash and wind blast; some also wear chaps or full leather pants to protect

470-401: A wide variety of sizes and lengths expressly for this purpose; they are usually a single piece which can be inserted by hand. Two-piece hard plastic devices are available which also grip the wire that passes through. These are called strain relief bushings and are often used to insulate, anchor, and protect power cords where they enter panels. Preventing a tug or twist on the wire from stressing

517-416: Is a process that stabilizes the proteins , particularly collagen , of the raw hide to increase the thermal, chemical and microbiological stability of the hides and skins, making it suitable for a wide variety of end applications. The principal difference between raw and tanned hides is that raw hides dry out to form a hard, inflexible material that, when rewetted, will putrefy , while tanned material dries to

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564-534: Is also used for falconry jesses, soccer footwear, (e.g. Adidas Copa Mundial ) and boxing speed bags. Although originally raised for their feathers in the 19th century, ostriches are now more popular for both meat and leather. Ostrich leather has a characteristic "goose bump" look because of the large follicles where the feathers grew. Different processes produce different finishes for many applications, including upholstery, footwear, automotive products, accessories, and clothing. In Thailand , stingray leather

611-411: Is called bating. Lipases are used in the degreasing operation to hydrolyze fat particles embedded in the skin. Amylases are used to soften skin, to bring out the grain, and to impart strength and flexibility to the skin. These enzymes are rarely used. The natural fibers of leather break down with the passage of time. Acidic leathers are particularly vulnerable to red rot , which causes powdering of

658-405: Is divided into three fundamental subprocesses: preparatory stages, tanning, and crusting. A further subprocess, finishing, can be added into the leather process sequence, but not all leathers receive finishing. The preparatory stages are when the hide is prepared for tanning. Preparatory stages may include soaking, hair removal, liming , deliming , bating , bleaching , and pickling . Tanning

705-452: Is one of the most exploited reptile species in the world in the leather trade. However, it is not endangered and while monitored, trade is legal in most South American countries. Kangaroo leather is used to make items that must be strong and flexible. It is the material most commonly used in bullwhips . Some motorcyclists favor kangaroo leather for motorcycle leathers because of its light weight and abrasion resistance. Kangaroo leather

752-427: Is quite common in applications that range from telecom switches and data center cabinets to complex and dense wire/cable and even hydraulic tubing in aircraft, transportation vehicles and medical equipment. Grommets are typically used to reinforce holes in leather , cloth , shoes , canvas and other fabrics . They can be made of metal , rubber , or plastic , and are easily used in common projects, requiring only

799-545: Is used in wallets and belts. Stingray leather is tough and durable. The leather is often dyed black and covered with tiny round bumps in the natural pattern of the back ridge of an animal. These bumps are then usually dyed white to highlight the decoration. Stingray rawhide is also used as grips on Chinese swords, Scottish basket hilted swords, and Japanese katanas . Stingray leather is also used for high abrasion areas in motorcycle racing leathers (especially in gloves, where its high abrasion resistance helps prevent wear through in

846-648: The eardrum to allow air to pass through into the middle ear, and thus release any pressure buildup and help clear excess fluid within. This is also a correcting measure for a patulous Eustachian tube (when air moves to and from the middle ear with each breath making the eardrum flap). Leather Leather is a strong, flexible and durable material obtained from the tanning , or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle , sheep , goats, equine animals, buffalo, pigs and hogs, and aquatic animals such as seals and alligators. Leather can be used to make

893-589: The 1970s and 80s) are well known for wearing leather clothing. Extreme metal bands (especially black metal bands) and Goth rock groups have extensive black leather clothing. Leather has become less common in the punk community over the last three decades, as there is opposition to the use of leather from punks who support animal rights . Many cars and trucks come with optional or standard leather or "leather faced" seating. In countries with significant populations of individuals observing religions which place restrictions on material choices, vendors typically clarify

940-431: The cord from tearing through the hole, thereby providing structural integrity. Small grommets are also called eyelets, especially when used in clothing or crafting. Eyelets may be used purely decoratively for crafting. When used in sailing and various other applications, they are called cringles . Sometimes field workers refer to them as grunyons . Traditionally, rope grommets have been widely used on sailing ships in

987-561: The design to consist only of four panels, which would be light enough for four boys to each carry one to the campsite in their packs. Originally the panels had buttons with the same spacing used in German military tents, which the Scouts and Youth Movement groups had previously used; these were replaced with loops for lashing the panels together. The use of two lashed tent poles also developed at this time, initially together with four set perpendicularly in

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1034-421: The drive in place pass through grommets that decouple it acoustically from the chassis. Grommets are used in a similar way to acoustically isolate electronic circuit components that are susceptible to microphonism caused by mechanical vibration or jarring. In chronic cases of otitis media with effusions present for months, surgery is sometimes performed to insert a grommet, called a " tympanostomy tube " into

1081-559: The electrical connections inside the connected equipment. Sleeved grommets have a flexible extension (sleeve), usually tapered or moulded to flex increasingly towards the free end in order to reduce fracturing of electrical insulation. Grommets made of rubber or other elastic material are also used to minimize the transmission of vibration. They were widely used for mounting shock-sensitive computer disk drives , particularly in equipment subject to vibration or jarring, but are not usually used with more robust modern drives. The screws that hold

1128-679: The event of an accident). For a given thickness, fish leather is typically much stronger due to its criss-crossed fibers. Leather produces some environmental impact, most notably due to: Estimates of the carbon footprint of bovine leather range from 65 to 150 kg of CO 2 equivalent per square meter of production. One ton of hide or skin generally produces 20 to 80 m of waste water, including chromium levels of 100–400 mg/L, sulfide levels of 200–800 mg/L, high levels of fat and other solid wastes, and notable pathogen contamination. Producers often add pesticides to protect hides during transport. With solid wastes representing up to 70% of

1175-522: The exit point of the casing of a junction box for example. Rubber, plastic or plastic coated metal grommets are used to avoid this. Tight fitting rubber grommets can also prevent the entry of dirt, air, water, etc. The smooth and sometimes soft inner surface of the grommet shields the wire from damage. Grommets are generally used whenever wires pass through punched or drilled sheet metal or plastic casings for this reason. Molded and continuous strip grommets, also known as edge grommets, are manufactured in

1222-452: The following grades: The term "genuine leather" does not describe a specific grade. The term often indicates split leather that has been extensively processed, and some sources describe it as synonymous with bicast leather, or made from multiple splits glued together and coated. In some countries, when it is the description on a product label the term means nothing more than "contains leather"; depending on jurisdiction, regulations limit

1269-740: The grommet itself and a means of setting it. A simple punch , a metal rod with a convex tip, is often sold with the grommets. It can be struck with a hammer to set the grommet. It can alternatively be set with an electronic, pneumatic, or gas-powered machine. There are also dedicated grommet presses with punch and anvil , as shown in the picture, ranging from inexpensive to better-quality tools, which are somewhat faster to use. Typical applications are footwear for boot and shoe laces, in laced clothing such as corsets , in flags for hoisting, and in curtains and other household items that require hanging from hooks, as when they are used in conjunction with tensioner rods for shower curtains. The grommet prevents

1316-543: The ground, to which the crossed sticks were secured. Koebel came to prefer black tents, as less disturbing in the natural landscape. The coloured bands were replaced with a tradition of decorating the black tents with hand-drawn designs. Koebel's Berlin group, the Deutsche Jungenschaft vom 1.11.1929 , held its first winter camp with kohtes in the Black Forest in 1931–32. At some point in the early 1930s, this form of

1363-761: The kohte began to be mass manufactured and was sold as single panels and as a kit together with pre-cut bamboo poles, tent pegs, and the sticks for suspension, through Tadep, the group's official outfitter. After the Nazis came to power and replaced the youth movements with the Hitler Youth and League of German Girls , in 1935 Artur Axmann , the leader of the Hitler Youth in Berlin, banned the kohte as an indication of an "anti-Volkish" and "cultural Bolshevist" mindset, and those who continued to use it were prosecuted. After World War II ,

1410-612: The kohte was reintroduced and it became the most used type of tent in German Scouting . It is also common in Austria. Grommet A grommet is a ring or edge strip inserted into a hole through thin material, typically a sheet of textile fabric, sheet metal or composite of carbon fiber, wood or honeycomb. Grommets are generally flared or collared on each side to keep them in place, and are often made of metal , plastic , or rubber . They may be used to prevent tearing or abrasion of

1457-440: The leather. Chemical damage can also occur from exposure to environmental factors, including ultraviolet light, ozone, acid from sulfurous and nitrous pollutants in the air, or through a chemical action following any treatment with tallow or oil compounds. Both oxidation and chemical damage occur faster at higher temperatures. There are few methods to maintain and clean leather goods properly such as using damp cloth and avoid using

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1504-399: The liquor's pH in a process called basification, which fixes the tanning material to the leather. The more tanning material fixed, the higher the leather's hydrothermal stability and shrinkage temperature resistance. Crusting is a process that thins and lubricates leather. It often includes a coloring operation. Chemicals added during crusting must be fixed in place. Crusting culminates with

1551-480: The lower body. Leather's flexibility allows it to be formed and shaped into balls and protective gear. Subsequently, many sports use equipment made with leather, such as baseball gloves and the ball used in cricket and gridiron football . Leather fetishism is the name popularly used to describe a fetishistic attraction to people wearing leather, or in certain cases, to the garments themselves. Many rock groups (particularly heavy metal and punk groups in

1598-453: The manufacturer. A vertical base may be added under the panels. The tent is suspended by means of two crossed sticks from two long poles that are lashed together to form a V shape or A-frame , usually outside the tent; it can also be secured to an overhanging tree branch. It is secured to the ground with pegs . Traditionally, both the poles and the pegs are cut on-site rather than transported. The assembled tent sleeps four to eight and has

1645-400: The natural oils remaining in the leather itself, which can be washed out through repeated exposure to water. Frequent oiling of leather, with mink oil , neatsfoot oil , or a similar material keeps it supple and improves its lifespan dramatically. Tanning processes largely differ in which chemicals are used in the tanning liquor. Some common types include: In general, leather is produced in

1692-780: The pierced material or protection from abrasion of the insulation on the wire, cable, line being routed through the penetration, and to cover sharp edges of the piercing, or all of the above. A small grommet may also be called an eyelet , used for example on shoes, tarps and sails for lacing purposes. Grommets in electrical applications are referred to as "insulating bushings". Most common are molded rubber bushings that are inserted into hole diameters up to 2″ (51 mm). There are many hole configurations from standard round to assorted U-shapes. Larger penetrations that are irregular in shape as well as long straight edges are often fitted with extruded or stamped strips of continuous length, referred to as "grommet edging". This type of protective bushing

1739-530: The regulations currently in force in some countries." In Kanpur , the self-proclaimed "Leather City of World"—with 10,000 tanneries as of 2011 and a city of three million on the banks of the Ganges —pollution levels were so high, that despite an industry crisis, the pollution control board decided to shut down 49 high-polluting tanneries out of 404 in July 2009. In 2003 for instance, the main tanneries' effluent disposal unit

1786-468: The shell. It is prized for its mirror-like finish and anti-creasing properties. Lamb and deerskin are used for soft leather in more expensive apparel. Deerskin is widely used in work gloves and indoor shoes. Reptilian skins, such as alligator , crocodile, and snake , are noted for their distinct patterns that reflect the scales of their species. This has led to hunting and farming of these species in part for their skins. The Argentine black and white tegu

1833-537: The source of leather in their products. Such labeling helps facilitate religious observance, so, for example, a Muslim will not accidentally purchase pigskin or a Hindu can avoid cattleskin. Such taboos increase the demand for religiously neutral leathers such as ostrich and deer . Judaism forbids the comfort of wearing leather shoes on Yom Kippur , Tisha B'Av , and during mourning. Also, see Leather in Judaism , Teffilin and Torah Scroll . Jainism prohibits

1880-400: The surface and a change in consistency. Damage from red rot is aggravated by high temperatures and relative humidities. Although it is chemically irreversible, treatments can add handling strength and prevent disintegration of red rotted leather. Exposure to long periods of low relative humidities (below 40%) can cause leather to become desiccated, irreversibly changing the fibrous structure of

1927-440: The term's use in product labelling. Today, most leather is made of cattle (cow) hides, which constitute about 65% of all leather produced. Other animals that are used include sheep (about 13%), goats (about 11%), and pigs (about 10%). Obtaining accurate figures from around the world is difficult, especially for areas where the skin may be eaten. There are significant regional differences in leather production: i.e. goat leather

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1974-457: The weekend of 8 April 2017 in the neighborhood. The higher cost associated with the treatment of effluents than to untreated effluent discharging leads to illegal dumping to save on costs. For instance, in Croatia in 2001, proper pollution abatement cost US$ 70–100 per ton of raw hides processed against $ 43/t for irresponsible behavior. In November 2009, one of Uganda's main leather making companies

2021-724: The wet weight of the original hides, the tanning process represents a considerable strain on water treatment installations. Leather biodegrades slowly—taking 25 to 40 years to decompose . However, vinyl and petrochemical-derived materials take 500 or more years to decompose. Tanning is especially polluting in countries where environmental regulations are lax, such as in India, the world's third-largest producer and exporter of leather. To give an example of an efficient pollution prevention system, chromium loads per produced tonne are generally abated from 8 kg to 1.5 kg. VOC emissions are typically reduced from 30 kg/t to 2 kg/t in

2068-544: Was caught directly dumping waste water into a wetland adjacent to Lake Victoria . Enzymes like proteases , lipases , and amylases have an important role in the soaking, dehairing, degreasing, and bating operations of leather manufacturing. Proteases are the most commonly used enzymes in leather production. The enzyme must not damage or dissolve collagen or keratin , but should hydrolyze casein , elastin , albumin , globulin -like proteins, and nonstructural proteins that are not essential for leather making. This process

2115-576: Was dumping 22 tonnes of chromium-laden solid waste per day in the open. In the Hazaribagh neighborhood of Dhaka in Bangladesh , chemicals from tanneries end up in Dhaka's main river. Besides the environmental damage, the health of both local factory workers and the end consumer is also negatively affected. After approximately 15 years of ignoring high court rulings, the government shut down more than 100 tanneries

2162-546: Was historically called "Turkey" or "Morocco" due to its association with the Middle East, while pig skin had historically been used the most in Germany. Other animals mentioned below only constitute a fraction of a percent of total leather production. Horse hides are used to make particularly durable leathers. Shell cordovan is a horse leather made not from the outer skin but from an under layer, found only in equine species, called

2209-454: Was presented in summer 1928 at a camp at the Kollenburg near Dorfprozelten , but resembled a teepee : it was supported by many poles that crossed at the top, transported to the site as rail luggage, and the panels were sewn together and were white with coloured upper and lower sections. After his move to Berlin in 1930, Koebel and a friend who was then an engineering student, Ernst Voos, refined

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