Self
- Clinching Glossary of Terms
anvil - An
insert, either solid or hollow, which is used on the underside of a
panel to resist the installation force.
blind - A
hole, usually threaded, which is open from only one end.
broaching
- The act of cutting a shape in any object by using a mandrel of a similar
shape. As applied to fasteners, the way a knurled shank "broaches"
its way into the mounting hole.
captive -
The ability of a fastener to remain securely attached to a panel.
captive screw
- See: panel fastener.
chamfer -
A beveled edge or corner.
cold flow
- The movement of a ductile material under pressure.
concealed-head
- A type of fastener which, when installed, is completely hidden when
viewed from the reverse side.
ductile -
Metal which is not brittle and can be easily formed or bent.
floating
- The ability of a fastener to move in a direction parallel to the mounting
panel and allow for mating hole misalignment.
flush - The
ability of a fastener to be contained completely within the thickness
of a panel. Also refers to the absence of a protrusion above the surface
of the panel.
head - The
portion of a fastener which forms its largest diameter.
installation
force - A term expressed in pounds, tons or newtons applied axially
to a self-clinching fastener to achieve proper installation.
interference
fit - The insertion of one member into another whose diameter is
slightly smaller than the part being inserted.
knurled clinching
ring - The displacer portion of a fastener which has corrugations
and is used to develop torque resistance when installed in sheet metal.
locking element
- A device employed to restrict rotation of a threaded member while
operating in adverse environments, such as vibration and temperature.
The nut-locking element provides prevailing locking torque to the mating
screw.
minimum distance
- The minimum distance from the center of a fastener mounting hole to
the nearest edge of a panel which will keep the edge from deforming.
This distance may be reduced by suitable fixturing or increasing thickness
of panel material.
minimum sheet
thickness - The thinnest section of a panel, usually measured in
thousandths of an inch or millimeters, into which a fastener may properly
be installed. The same fastener may be installed in panels having any
thickness greater than minimum.
mounting hole
- A properly-sized round opening in a panel to receive the shank of
a self-clinching fastener.
panel fastener
- A threaded screw which is held captive to a panel and which, when
disengaged from its main nut, remains fixed to that panel.
pin - A captive
post that extends from a panel.
plunger assembly
- A spring loaded device used for latching or indexing purposes.
positive stop
- A visual indication that the proper depth of penetration of the knurled
ring has occurred or when the "head" is in contact with the
top surface of the panel. Synonym: shoulder.
pull-through
- The resistance of a fastener to a force applies in the same direction
to which is was installed.
punch - A
movable insert, either solid or hollow, which applied an installation
force to the top of the fastener.
pushout -
The force required to remove a fastener from a panel in a direction
opposite to the way from which it was installed. Note: pushout is expressed
in pounds or newtons.
rockwell hardness
- A relative measure of hardness. Rockwell C Scale is used for hard
materials, Rockwell B for softer materials, such as sheet metal.
self-clinching (also self-clinch or clinching)
- The method by which a fastener is securely attached to a sheet of
ductile material by causing the material to cold flow under pressure
into an annular recess of the fastener thereby securely locking it in
place.
self-locking
- A locking element, formed as an integral part of a fastener, which
provides force to restrict the rotational movement of a threaded member.
shank - The
portion of a fastener, which is slightly smaller than the fastener's
mounting hole and provides a positive location for the fastener in the
hole. A shank also incorporates an annular groove which becomes filled
with panel material as the fastener is installed, and the retention
of this material provides pushout resistance.
shank length
- The actual length of that portion of a fastener which is embedded
in the panel material.
shoulder
- The surface area of a fastener which contacts the top surface of the
sheet material. See: positive stop.
spring-loaded
- A device having a separate movable component that is biased in one
direction by a spring.
standoff
- A tubular device, usually threaded, for spacing or stacking components.
stud - A
male threaded captive post that extends from a panel.
swaging -
An operation whereby a reduced diameter of a fastener is deformed to
secure it to a panel. Note: the antonym of swaging is self-clinching
where the panel material is caused to deform.
thread class
- A measure of clearance or fit between the screw and the nut taken
at the pitch diameter.
threaded insert
- A threaded device which is installed in a panel material.
throughhole
- A hole, threaded or not threaded, which transverses the entire length
of a part and is usable from either end.
tolerance
- The absolute amount of maximum or minimum dimensional deviation allowed
that will not affect the performance of a mechanical part.
torque-out
- The amount of torque necessary to spin the fastener out of the sheet.
This is torque applied to the fastener. No axial load is applied.
torque-through
- The amount of torque necessary to fail the fastener in axial load.
undercut
- The reduced diameter of a fastener which receives sheet material when
a fastener is installed. Depending on the type of fastener, may be rectangular
or back tapered in shape.
