Glossary

Glossary

A | B | C | D | F | J | K | N | P | S | V | W

Term Definition
A (index)
A2 Stainless Steel A2 stainless is also called 303 stainless or 304 stainless steel. It can also be called 18/8 because it approximately contains 18% Chromium and 8% Nickel. It is an austenitic non magnetic steel. The Chromium gives the metal corrosion protection properties, although it can still oxidise (tarnish). It is commonly used for fasteners in food, dairy and agriculture businesses because it is safe to use with food. A2 comes in three different property classes 50 (500 N/mm2), 70 (700 N/mm2) and 80 (800 N/mm2) tensile strengths.
ACME Thread An American screw thread having a section that is a mean between the V threads and square threads. It has a 29 degree included angle, and is mainly used for feeds and adjusting screws on machine tools.
Acorn Nut A nut shaped with an acorn head that 'caps' the top. An acorn nut, also referred to as crown hex nut, blind nut, cap nut, domed cap nut, or dome nut. When used with a bolt, setscrew or threaded end, the domed end encloses the external thread of the threaded fastener, either to protect the thread itself or to protect nearby objects from contact with the thread. In addition, the dome gives a more finished appearance.
Aerotight Nut A special vibration resistant self locking nut (also known as stiffnuts), which self lock due to slots in two places (located on the top of the nut), these slots are then bent slightly inwards and downwards after the nut has been tapped. When the nut is screwed onto a bolt thread, the two slotted parts are forced back to their original position locking and securing the nut in place.
Allthread Round bar that is threaded throughout its entire length (ususally specified by the customer), is available in all thread types and grades.
Anco nuts Mainly used in the petro-chemical industry, it is an all metal construction self lock nut containing a stainless steel ratchet pin. The nut prevents damage to coatings and damage to the bolt threads.
Angle controlled tightening "A method of tightening in which a fastener e.g a nut is first tightened so the clamped surfaces are pulled towards one another, it is tightened further by giving the nut an additional measured rotation such as a 1/4 turn in order to ensure a precise preload is achieved.
Annealing Annealing is a process where a material is heated and gradually cooled in order to remove stress and change the materials ductility. This method is done prior to cold forging, however can be done to fasteners once they have been heated to a precise temperature (depending on the material and the customers specification) followed by a slow and steady cooling process.
Anodizing Anodizing is a process used to form a layer of aluminium oxide layer on a base material, this is done to minimise the risk of corrosion.
ANSI The American National Standards Institute is a private non-profit making organisation that oversees the development fastener product standards in the United States.
ASME The dimensional standards for fasteners, developed by the american society of mechanical engineers
B (index)
Barrel nut An internally threaded scew with a slotted head, used in the furniture industry.
Basic thread profile This is the theoretical profile of external and internal threads with no manufacturing tolerance applied
Bearing Nuts Bearing nuts are also known as slotted hook nuts and are used to lock bearing onto shafts and shafts onto housings
Bearing stress The surface pressure acting on a joint face directly as a result of the force applied by a fastener
Belleville washer Also known as a coned-disc spring, conical spring washer, or cupped spring washer, is a type of spring shaped like washer, its frusto-conical shape gives the washer a spring like characteristic. The Belleville name comes from the inventor Julian Belleville who patented the design in France in 1867
Bi-hexagon head bolt or screw whose cross section of its head is in shape is in the shape of a 12 pointed star, also called 12 point bolts and ferry bolts
BI-lock nuts Centre lock and bi lock nuts have deformed threads in the centre of the nut acting as an all metal prevailing torque thread locking mechanism
Binx nut Binx nuts have two slots on the head of the nut and are dimensionally no bigger than a standard full nut.
Blind Nut A nut shaped with an acorn head that 'caps' the top. An acorn nut, also referred to as crown hex nut, blind nut, cap nut, domed cap nut, or dome nut. When used with a bolt, setscrew or threaded end, the domed end encloses the external thread of the threaded fastener, either to protect the thread itself or to protect nearby objects from contact with the thread. In addition, the dome gives a more finished appearance.
C (index)
cage nuts also called captive and clip nuts, these usually consist of a square nut in a spring steel cage which wraps around the cut, the cage has two wings that when compressed allow the cage to be inserted into the square holes in the plate material.
Cap Nut A nut shaped with an acorn head that 'caps' the top. An acorn nut, also referred to as crown hex nut, blind nut, cap nut, domed cap nut, or dome nut. When used with a bolt, setscrew or threaded end, the domed end encloses the external thread of the threaded fastener, either to protect the thread itself or to protect nearby objects from contact with the thread. In addition, the dome gives a more finished appearance.
Castellated Nut A castellated nut, sometimes referred to as a castle nut, is a nut with slots (notches) cut into one end which has a reduced diameter portion. A pin is then inserted across the slots and into a predrilled hole on a mating fastener. This then locks the nut in place.
Castle Nut A castle nut, is a nut with slots (notches) cut into one end which has a reduced diameter portion. A pin is then inserted across the slots and into a predrilled hole on a mating fastener. This then locks the nut in place.
Chimney nut Spring sheet metal clips used to put a thread on a sheet plate, used in conjunction with machine screws.
Cleveloc nut A torque nut has an elliptical csa collar which provides the flexible locking element.
Coupling nut a long nut designed to connect threaded assemblies together.
Crown Hex Nut A nut shaped with an acorn head that 'caps' the top. An acorn nut, also referred to as crown hex nut, blind nut, cap nut, domed cap nut, or dome nut. When used with a bolt, setscrew or threaded end, the domed end encloses the external thread of the threaded fastener, either to protect the thread itself or to protect nearby objects from contact with the thread. In addition, the dome gives a more finished appearance.
D (index)
Dome Nut A nut shaped with an acorn head that 'caps' the top. An acorn nut, also referred to as crown hex nut, blind nut, cap nut, domed cap nut, or dome nut. When used with a bolt, setscrew or threaded end, the domed end encloses the external thread of the threaded fastener, either to protect the thread itself or to protect nearby objects from contact with the thread. In addition, the dome gives a more finished appearance.
F (index)
flex loc nuts The locking threads of the slotted top press in against the bolt, lifting the nut upwards and causing the remaining threads to bear against the lower surface of the bolt threads.
J (index)
Jack nuts Jack nuts (or molly nuts) are threaded inserts. The jack nut is a lightweight threaded fastener ideal for use on thin, soft or brittle materials. When setting, the legs of the jack nut anchor on the underside of the material. Used extensively in vacuum and rotational moulding applications.
Jam nuts American term for lock nuts, two lock nuts are jammed together, the term JAM is used for thin nuts used to lock against a second nut.
K (index)
Keps nut a kep nut is a pre-assembled captive nut and shakeproof washer assembly, the washer is attatched to the nut so it doesn�t fall off.
N (index)
Nyloc nut A torque retaining nut that uses a patented nylon insert as means of a locking feature. The nylon insert helps to seal the bolt thread against seepage of water, oil, petrol, paraffin and other liquids. The nut is covered by UK patent 8028437 and EU patent 81303450-1
P (index)
Palnut a palnut is a locking device used for nuts made of stamped sheet metal. The palnut is screwed on top of the bolt of an ordinary nut and has a series of protruding barbs that lock the nut in place when the nut is tightened.
Philidas nuts The nut is slotted in two places on the top of the nut but horizontally on two sides of the nut. This type of nut has a similar method of locking like the Aerotight nuts, after tapping the slots are bent slightly inwards and downwards so that when the nut is screwed onto a bolt thread, the slotted parts will be forced back into their original position, the stiffness causes to the nut threads to bind onto the bolt and provides torque locking.
S (index)
Serrated flange nuts Flange nuts have intergral washer flanges, serrations can be added to the flange to produce a locking element
Slotted nut Castle nuts are typically hex nuts with usually 6 slots (60 degrees apart) in a reduced diameter round section above the wrenching part. When a castle nut (or any radially slotted nut) is applied to a threaded section, it is assumed that the rod has a hole drilled in it, into which a cotter pin, a lock wire or a spring pin is typically inserted to stop the nut from rotating.
V (index)
Vargal nut all metal locking nut which contains a spring, mainly used in the railway industry.
W (index)
Weld nut Very similar to standard square or hex nuts, but have a locating boss and welding projections (lugs, pips and nibs)
Wing nut single piece, round threaded nuts with wing lugs for ease of manual assembly. Particularly suited to applications where frequent removal, replacement or adjustment are required.
Words Definition