Bolts Types and Terms
Bolt Types
-
are made from cadmium to prevent corrosion and have threads rolled or
pressed into the bolt, which make the bolt much stronger than the cut
threads in a hardware bolt. Aircraft bolts are also tested in smaller
batches for quality and are used primarily by the military and aircraft
industries.
-
are long "L" shaped-style bolts that are set in concrete
to anchor columns or other supports to a foundation.
- produce bolts for various uses.
-
are bolts with a round head and are used for timber. Carriage bolts
are threaded on only part of the shank and are inserted into pre-drilled
holes.
-
have an attachment that expands as the bolt is driven into a surface.
- are
bolts with an eye at one end in place of a standard head.
- are
heavy woodscrews that have a square or hexagonal head, which is driven
in by a wrench.
-
are used by the international community and are measured using the metric
system as their defining classification.
-
are bolts whose shank diameter is smaller than the normal dimensions
for the bolt.
-
are used primarily for location of pivot mounting. The shaft that is
not threaded has a wider diameter, giving the bolt a shouldered appearance.
- are used for applications where strength and resistance to corrosion is desired.
-
are made to resist vibration loosening. Step lock bolts have several
portions of horizontal threads called steps.
-
are small-sized machine bolts.
-
are U-shaped bars that have bolts and threads at both ends but not in
the middle. U-bolts are primarily used in suspension areas of vehicles.
Bolt Terms
- A tightening method in which the surfaces are pulled together
by tightening the fastener with a pre-selected (snug) torque. The nut
is given an extra measured rotation, further tightening the fastener,
often beyond its yield point to ensure the achievement of a precise preload.
-
Dry lubricants that are comprised of suspensions of solid lubricants of
small particle size, such as graphite or PTFE.
- A compound
that is applied to the threads of fasteners and whose purpose depends
on the application. Anti-seize compounds can prevent galling or mating
surfaces, improve corrosion resistance or provide a barrier to water penetration
by sealing the threads.
- The surface
pressure acting on a joint face, resulting from the clamping force applied
by a fastener.
- A term that refers to
the comparatively wider tolerances employed in the manufacturing of nuts
and bolts, not necessarily the color of the surface finish.
- The compressive
force exerted on a joint by a fastener.
- The measure of
the degree of fit between mating external and internal threads. There
are three main Classes of Fit for metric screw threads: fine, medium and
coarse.
- The permanent deformation
of a bolt or other fastener resulting from the application of stress and
heat.
-
Forming threads on a fastener by cutting away and actually removing the
unneeded metal.
-
The degree of difference between the centers of the surface of a bolt
at different points.
- The fracture
resistance of bolts during subjection to stress variations.
- The
thickness of all materials that a bolt is designed to secure.
- The top portion of a
bolt. A head also refers to the portion of a fastener that forms its largest
diameter.
- The
material(s) that the fastener (bolt) connects together.
- A small metal piece with
a hole in the center that fits over a bolt or over the end of a bolt.
Nuts are often hexagonal (6-sided) in shape.
- The amount of force
required to pull the fastener out of the base material.
- The portion of a headed
fastener that lies between the head and the point.
- The amount
of longitudinal load/elongation a fastener can withstand without failure
of the fastener or joint.
- A raised helical pattern
going around the shank of a bolt. The thread is measured by pitch, which
is the distance from one peak of the thread to the next, expressed in
mm or threads per inch.
- The amount
of force at which a threaded fastener, an insert or nut begins to strip
or otherwise fail in a joint.