A ferrule (a corruption of Latin viriola "small bracelet", under the influence of ferrum "iron") is any of a number of types of objects, generally used for fastening, joining, sealing or reinforcement. They are often narrow circular rings made from metal, or less commonly, plastic. Ferrules are also often referred to as eyelets or grommets within the manufacturing industry.[1]

Most ferrules consist of a circular clamp used to hold together and attach fibers, wires, or posts, generally by crimping, swaging, or otherwise deforming the ferrule to permanently tighten it onto the parts that it holds.

Wire rope with thimble and ferrule
A wire rope terminated with a thimble and a ferrule
Picco pipe with nickel silver ferrule
Non-circular ferrules holding bristles to brushes


  • The plastic sleeve preventing the ends of shoelaces from unraveling (called the aglet)
  • The metal sleeve which is crimped to hold the eraser in place on pencils
  • The metal band that binds the bristles or hair of a brush to its handle
  • The metal ring which holds a chisel blade's tang to the handle
  • In fiber optic terminations, glass or plastic fibers are bonded to precision ferrule connectors (FCs), also described as fiber channel connectors, and polished for splitting or connecting two fibers together[2]
  • The metal spike at the end of the shaft of an ice axe
  • The margin of a cast crown that stabilizes root-canal-treated teeth in restorative dentistry[3]
  • A ferrule, in respect to dentistry, is a band that encircles the external dimension of residual tooth structure, not unlike the metal bands that exist around a barrel. This is also known as the Ferrule Effect.
  • The bottom end of a flagstick on a golf course, which fits snugly into a hole in the cup
  • The plastic sleeve that adorns the bottom of most steel and graphite golf club shafts just above the club head hosel. Originally designed to protect the shaft from damaging vibrations, it is now used mainly for aesthetic purposes
  • The metal band used to prevent the ends of wooden instruments from splitting
  • The semi-circular metal band that holds the fibers in place on the frogs of bows for violin family instruments
  • Compression fittings for attaching tubing (piping) commonly have ferrules in them.
  • A swaged termination type for wire rope
  • The cap at the end of a cane or umbrella as well as the ring, often crimped, sometimes pinned, that prevents an umbrella's canopy from sliding off the end when open.
  • The portion of a cue in pool, billiards and snooker that tops the shaft and to which the tip is bonded; historically made of ivory, now typically made of fiberglass, phenolic resin or brass
  • The male and female joints that join one section of a two-piece fishing rod
  • A metal cap at the end of cable housing with a hole on bicycle or motorcycle control cables
  • The metal sleeve that connects a hypodermic needle to a plastic Luer taper (which then connects to a syringe or intravenous therapy tubing.)
  • An electric wire ferrule is metal tube crimped over stranded wire to secure it within a screw terminal usually with electrical insulation protecting any exposed portion of the wire not completely inside the screw terminal post.
  • A metal or plastic ring used in plumbing as part of a compression fitting along with a slip-on nut for making a liquid-tight connection when joining pipe or tubing. (These are informally called "olives" in the U.K.)

Reasons for use

Some of the reasons people use ferrules include:[4]

  • To shield parts or cables from electromagnetic pulses, environmental damage, the elements, thermal factors, and more.
  • To cover parts, adding wear resistance, damage protection, or packaging.
  • As a connector, to connect wires, structural devices, and systems
  • To bind parts together, including bundles of wires, or cloth threads to the end of the mop, as an example.
  • To act as conveyance for fluids like oil and water, or for gasses like air.


  1. ^ "Ferrules & Eyelets". Trans-Matic Manufacturing, Inc. Archived from the original on 19 April 2014. Retrieved 18 April 2014.
  2. ^ US patent 5016970, Mito Ryo Nagase; Machida Juichi Noda & Tachikawa Etsuji Sugita, "Ferrule for optical fiber transmitting linearly polarized light and optical fiber connector using this ferrule", issued 1991-05-21 (download PDF)
  3. ^ NIH search
  4. ^ "Ferrules & Eyelets". Trans-Matic Manufacturing, Inc. Archived from the original on 19 April 2014. Retrieved 18 April 2014.
Barong (knife)

The barong is a thick, leaf-shaped, single-edged blade sword. It is a weapon used by Muslim Filipino ethnolinguistic groups like the Tausug, Sinama or Yakan in the Southern Philippines.

Blackwing 602

The Blackwing 602 is a pencil that is noted for its soft, dark graphite, unique flat square ferrule and replaceable eraser. It was manufactured by the Eberhard Faber Pencil Company from 1934 - 1988, then by the Faber-Castell pencil company from 1988 - 1994 and by Sanford from 1994 - 1998. The pencil initially sold for 50 cents each. After it was discontinued single original pencils were found on eBay for over $40, with some older (and rarer) ones being sold for over $100. Originals are becoming increasingly rare. However, as of 2012 a pencil under the same name is again being manufactured by Palomino and is available in packages of 12 for about $20.

Bowden cable

A Bowden cable ( BOH-dən)

is a type of flexible cable used to transmit mechanical force or energy by the movement of an inner cable relative to a hollow outer cable housing. The housing is generally of composite construction, consisting of an inner lining, a longitudinally incompressible layer such as a helical winding or a sheaf of steel wire, and a protective outer covering.

The linear movement of the inner cable is most often used to transmit a pulling force, although push/pull cables have gained popularity in recent years e.g. as gear shift cables. Many light aircraft use a push/pull Bowden cable for the throttle control, and here it is normal for the inner element to be a solid wire, rather than a multi-strand cable. Usually, provision is made for adjusting the cable tension using an inline hollow bolt (often called a "barrel adjuster"), which lengthens or shortens the cable housing relative to a fixed anchor point. Lengthening the housing (turning the barrel adjuster out) tightens the cable; shortening the housing (turning the barrel adjuster in) loosens the cable.

Compression fitting

Compression fittings are used in plumbing and electrical conduit systems to join two tubes or thin-walled pipes together. In instances where two pipes made of dissimilar materials are to be joined (most commonly PVC and copper), the fittings will be made of one or more compatible materials appropriate for the connection. Compression fittings for attaching tubing (piping) commonly have ferrules (or olives in the UK) in them.

Compression fittings are also used extensively for hot and cold water faucets (taps) and toilet stop valves; compression fittings are well suited to this application, as these valves are usually located in confined spaces where copper pipe would be difficult to solder without creating a fire hazard. Also, the fittings allow easy disconnection and reconnection.

Crown (dentistry)

A crown, sometimes known as dental cap, is a type of dental restoration which completely caps or encircles a tooth or dental implant. Crowns are often needed when a large cavity threatens the ongoing health of a tooth. They are typically bonded to the tooth using a dental cement. Crowns can be made from many materials, which are usually fabricated using indirect methods. Crowns are often used to improve the strength or appearance of teeth. While inarguably beneficial to dental health, the procedure and materials can be relatively expensive.

The most common method of crowning a tooth involves using a dental impression of a prepared tooth by a dentist to fabricate the crown outside of the mouth. The crown can then be inserted at a subsequent dental appointment. Using this indirect method of tooth restoration allows use of strong restorative materials requiring time-consuming fabrication methods requiring intense heat, such as casting metal or firing porcelain which would not be possible to complete inside the mouth. Because of the expansion properties, the relatively similar material costs, and the cosmetic benefit, many patients choose to have their crown fabricated with gold.

As new technology and materials science has evolved, computers are increasingly becoming a part of crown fabrication, such as in CAD/CAM dentistry.

Crown lengthening

Crown lengthening is a surgical procedure performed by a dentist, or more frequently a specialist periodontist. There are a number of reasons for considering crown lengthening in a treatment plan. Commonly, the procedure is used to expose a greater amount of tooth structure for the purpose of subsequently restoring the tooth prosthetically. However, other indications include accessing subgingival caries, accessing perforations and to treat aesthetic disproportions such as a gummy smile. There are a number of procedures used to achieve an increase in crown length.

Cue stick

A cue stick (or simply cue, more specifically billiards cue, pool cue, or snooker cue), is an item of sporting equipment essential to the games of pool, snooker and carom billiards. It is used to strike a ball, usually the cue ball. Cues are tapered sticks, typically about 57–59 inches (about 1.5 m) long and usually between 16 and 21 ounces (450–600 g), with professionals gravitating toward a 19-ounce (540 g) average. Cues for carom tend toward the shorter range, though cue length is primarily a factor of player height and arm length. Most cues are made of wood, but occasionally the wood is covered or bonded with other materials including graphite, carbon fiber or fiberglass. An obsolete term for a cue, used from the 16th to early 19th centuries, is billiard stick.

Dixon Ticonderoga Company

The Dixon Ticonderoga Company () is an office and art supplies maker from the United States, with headquarters in Heathrow, Florida. The company offers a number of brands, with one of the most well-known being Ticonderoga - the yellow No. 2 pencil known for its distinctive green and yellow ferrule. Other brands include Dixon and Oriole pencils, Dixon Industrial products, Prang school and art supplies, and Lyra art products.

Electric wire ferrule

An electric wire ferrule (sometimes end terminal) is a metal tube crimped over stranded wire to secure the strands within a screw terminal. Electrical insulation may be included to protect any exposed portion of the wire not completely inside the screw terminal post.

Stranded wire is preferred for most electrical applications because it is more reliable than solid wire. It is more flexible and durable because repeated bending will not cause it to break. Stranded wire can be more difficult to terminate, because the individual strands tend to separate after insulation is removed.

By placing the end of the stranded wire in a ferrule, the strands stay together.

FC connector

The FC connector is a fiber-optic connector with a threaded body, which was designed for use in high-vibration environments. It is commonly used with both single-mode optical fiber and polarization-maintaining optical fiber. FC connectors are used in datacom, telecommunications, measurement equipment, and single-mode lasers. They are becoming less common, displaced by SC and LC connectors. The FC connector has been standardized in TIA fiber optic connector intermateability standard EIA/TIA-604-4.The FC connector was originally called a "Field Assembly Connector" by its inventors. The name "FC" is an acronym for "ferrule connector" or "fiber channel".

Fixed prosthodontics

Fixed prosthodontics is the area of prosthodontics focused on permanently attached (fixed) dental prostheses. Such dental restorations, also referred to as indirect restorations, include crowns, bridges (fixed dentures), inlays, onlays, and veneers. Prosthodontists are specialist dentists who have undertaken training recognized by academic institutions in this field. Fixed prosthodontics can be used to restore single or multiple teeth, spanning areas where teeth have been lost. In general, the main advantages of fixed prosthodontics when compared to direct restorations is the superior strength when used in large restorations, and the ability to create an aesthetic looking tooth. As with any dental restoration, principles used to determine the appropriate restoration involves consideration of the materials to be used, extent of tooth destruction, orientation and location of tooth, and condition of neighboring teeth.


A hakapik (Norwegian: gaff) is a club, of Norwegian design, used for killing seals. The hakapik is a multipurpose hunting tool—a heavy wooden club, with a hammer head (used to crush a seal's skull), and a hook (used to drag away the carcass) on the end.

Regulation Canadian hakapiks consist of a metal ferrule that weighs at least 340 g (12 oz) with a slightly bent spike not more than 14 cm (5.5 in) in length on one side of the ferrule and a blunt projection not more than 1.3 cm (0.5 in) in length on the opposite side of the ferrule and that is attached to a wooden handle that measures not less than 105 cm (3.4 ft) and not more than 153 cm (5 ft) in length and not less than 3 cm and not more than 5.1 cm (2 in) in diameter.The hakapik is favored by sealers because it allows them to kill the seal without damaging the pelt. Further, studies by American veterinary scientists on the use of the hakapik on the seal hunt carried out on Pribilof Islands of Alaska suggested that it is an efficient tool designed to kill the animal quickly and humanely when used correctly. A report by members of the Canadian Veterinary Medical Association in September 2002 confirmed this claim.

Natural trumpet

A natural trumpet is a valveless brass instrument that is able to play the notes of the harmonic series.

Optical fiber connector

An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so light can pass. Better connectors lose very little light due to reflection or misalignment of the fibers. In all, about 100 different types of fiber optic connectors have been introduced to the market.


A paintbrush is a brush used to apply paint or sometimes ink. A paintbrush is usually made by clamping the bristles to a handle with a ferrule. They are available in various sizes, shapes, and materials. Thicker ones are used with for filling in, and thinner ones are used for details. They may be subdivided into decorators' brushes used for painting and decorating and artists' brushes use for visual art.

Post and core

A post and core crown is a type of dental restoration required where there is an inadequate amount of sound tooth tissue remaining to retain a conventional crown. A post is cemented into a prepared root canal, which retains a core restoration, which retains the final crown.The role of the post is firstly to retain a core restoration and crown, and secondly to redistribute stresses down onto the root, thereby reducing the risk of coronal fracture. The post does not play any role in reinforcing or supporting the tooth and can in fact make it more likely to fracture at the root.When deciding whether or not a tooth requires a post and core crown rather than a conventional crown, the following must be established:

Presence of an adequate ferrule(coronal tooth structure)

Sufficient length of canal to retain a post

Curvature and overall anatomy of root canal system

Sufficient root (radicular) dentine thickness for post preparation

Restorability of toothThe benefit of placing a post into a root canal is improved retention of the crown. However there are also disadvantages, during the preparation for the post space there is a risk of perforation, a post can also make a tooth more likely to fracture, it makes future orthograde root canal treatment much more difficult and finally it is very destructive and requires excessive removal of tooth tissue. The presence of ferrule can increase the fracture resistance of the post.Posts are more commonly required for anterior teeth rather than posterior teeth. The primary reason for this is that multi-rooted teeth have a large pulp chamber which can be utilised for retention of the core and therefore the crown, whereas anterior teeth are much smaller and less retentive.When it is not possible to retain a core on a posterior tooth and a post is required, no more than one post should be used per tooth, and this should be placed in the largest canal available. This is because more than one preparation for a post will involve excessive dentine removal and increase the fracture risk. A better alternative to posts on a posterior tooth is the use of a Nayyar core restoration which extends down into the entrance of the root canal.ProcedurePost and cores divide into two main groups: prefabricated and cast. Both of these systems employ a post that is placed within the root canal of the tooth being restored. Thus the tooth must first be endodontically treated. After the endodontic procedure has been completed, and the root canal(s) is/are filled with the inert gutta percha root canal filling material, some gutta percha is removed from the canal space. Gutta Percha can be removed mechanically(use of Gates Glidden), thermally(use of System B Tip), and chemically(use of chemical solvents, however this method is not advocated nowadays due to difficulty in controlling the depth of softening) The space that exists coronal to the remaining gutta percha, called the post space, is now available within which to place a post. It is desirable to leave sufficient root filling material in the apical area to maintain an apical seal. This procedure does not even require local anesthesia as the tooth has long been dead after the root canal treatment and no pain is felt.


A quarterstaff (plural quarterstaffs or quarterstaves), also short staff or simply staff is a traditional European pole weapon, which was especially prominent in England during the Early Modern period.

The quarterstaff has some advantages over the longsword; it is visually nonthreatening but can be just as deadly, and will even be more dangerous to an armored person than a longsword.The term is generally accepted to refer to a shaft of hardwood from 6 to 9 feet (1.8 to 2.7 m) long, sometimes with a metal tip, ferrule, or spike at one or both ends.

The term "short staff" compares this to the "long staff" based on the pike with a length in excess of 11 to 12 feet (3.4 to 3.7 m). The height of the staff should be around the same as the user plus their hand set upright on their head (usually about 20 centimeters).

Talurit swaged sleeve

A talurit swaged sleeve is used in a mechanical splicing system, to make an eye splice in a steel wire rope. The most common and useful type of end fitting for a wire rope is to turn the end back to form a loop. A thimble can be installed inside the loop to preserve the natural shape of the loop and protect the cable from pinching and abrading on the inside of the loop. The loose end is then fixed back on the wire rope by means of a swaged sleeve (ferrule). The thimble prevents disrupting of the wires.

The original T-ferrule design is the seamless aluminium ferrule, intended for galvanized or bright wire ropes. It corresponds to European standard, EN 13411-3. From size 8 and upwards fully traceable (ISO 9001) and marked with size, type and manufacturing batch number.

The UM-ferrule (Ultagrip Metal) is a cylindrical ferrule, smaller in diameter after pressing than the T-ferrule.

The seamless ferrule made from carbon steel is aimed for bright and galvanized steel wire ropes. Using the same metals between rope and ferrule prevents electrolytic corrosion. They are intended for applications with high temperatures and/or abrasion, e.g. the steel melting and fishing industries. From size 8 and upwards they are fully traceable (ISO 9001) and marked with size and type.

Ferrules made of copper and stainless steel.

The round R-ferrule is intended to be pressed on single wire ropes, e.g. on preventer wires or used as end stop.

Wood carving

Wood carving is a form of woodworking by means of a cutting tool (knife) in one hand or a chisel by two hands or with one hand on a chisel and one hand on a mallet, resulting in a wooden figure or figurine, or in the sculptural ornamentation of a wooden object. The phrase may also refer to the finished product, from individual sculptures to hand-worked mouldings composing part of a tracery.

The making of sculpture in wood has been extremely widely practised, but survives much less well than the other main materials such as stone and bronze, as it is vulnerable to decay, insect damage, and fire. It therefore forms an important hidden element in the art history of many cultures. Outdoor wood sculptures do not last long in most parts of the world, so it is still unknown how the totem pole tradition developed. Many of the most important sculptures of China and Japan, in particular, are in wood, and so are the great majority of African sculpture and that of Oceania and other regions. Wood is light and can take very fine detail so it is highly suitable for masks and other sculpture intended to be worn or carried. It is also much easier to work on than stone.Some of the finest extant examples of early European wood carving are from the Middle Ages in Germany, Russia, Italy and France, where the typical themes of that era were Christian iconography. In England, many complete examples remain from the 16th and 17th century, where oak was the preferred medium.

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