Bolts Industry Information
IQS Newsroom Articles on Bolts
A bolt is a type of threaded fastener that utilizes a nut to secure the
other end of it to a desired surface. Many bolt manufacturers produce
industrial bolts
that are used for more high-stress industrial uses, such as
construction, and as components in the creation of larger industrial
parts, machines and vehicles. Most bolts are made out of
stainless steel,
but some are made with other materials, such as titanium and aluminum.
They are inserted into the material in multiple ways. Bolts can be
engaged with the use of handheld screwdrivers, high pressure drills and
allen wrenches. The nut, which attaches to the end of the shank, is
almost always hexagonal in shape. The military and aircraft industries
have specific bolt standards that require special anti-corrosive
coatings and materials. These bolts are tested under more rigorous
conditions, and therefore, are the preferred standard of the respective
industries. Bolts are used in nearly every industry, specifically in
building construction and automotive manufacturing. In the United
States, most bolts are measured by the American Measuring System.
However, Europe and Asia use the Metric System. Recently,
metric bolts
have become more popular in the United States because of international
businesses that need parts that are compatible with products from other
countries. Bolts come in many different sizes, shapes and materials.
Anchor bolts,
J bolts,
stud bolts,
expansion bolts, l
ag bolts,
U bolts,
eye bolts,
hex bolts and
shoulder bolts all have different specific uses and defining shapes.
Bolt
manufacturers designate bolts by the major diameter of the external
thread and the pitch measurement. A thread is a ridge that wraps around
the outside of a cylinder in a helical pattern. The ridge itself is
called the crest, while the space between the ridges is called the
root. Threads are set at an angle to the axis of the bolt and slope
either upward to the right (for right-hand threaded screws) or upward
to the left (for left-handed threaded screws). The slope of the thread
is known as the helix angle. The thread forms a V-shaped angle between
the crest, called the thread angle, which is determined by fastener
engineers. The distance from one crest of one thread to another crest
is called the pitch and is measured along the axis of the thread with a
thread pitch gauge.
Bolts are further
classified by bolt manufacturers according to the type of the top
portion, called the head. The head comes in a variety of shapes and
styles. Flat heads have an angle of 80-82Û and are used where finished
surfaces require a flush face. Round heads were commonly used in the
past, but are now being replaced by newer designs, such as pan heads.
Oval heads require the hole to be countersunk. Binding heads are
undercut, binded and eliminate the fraying of stranded wire in
electrical and radio work. Truss heads, also known as oven, stove or
oval binding heads, are used to cover large diameter clearance holes in
sheet metal. Other types of heads include holt, one-way, Phillips
Finishing Washer, washer and undercut heads.
The
manufacturing process to create standard metal bolts out of stainless
steel, titanium or aluminum takes many steps. First, a steel wire rod
is heated in a furnace for 30 hours and bathed in sulfuric acid to
remove any rust particles. It is also coated with phosphate that
prevents rusting and acts as a lubricant. The rods are then formed by
cold forging, where the rod is shaped at room temperature. It is forced
through dyes at high pressure and shaped into long, perfectly round
rods. After they are cut into shorter pieces, the rods go through a dye
that shapes a head on one end. The threading on the other end is done
by another cold forging method using high pressure rollers that press
in the thread pattern.
Anchor bolts are
generally embedded in concrete and used to anchor columns or other
supports to a foundation. There are two types-those that are bent like
an L with a threaded top, and anchor rods, which are straight and
threaded on both ends. They are used in construction and in securing
traffic signal poles. U bolts are named for their shape-they are bent
bolts with threads at both ends. They may be round, square or
semi-round and used when suspended items need to be attached to the
surface of something. U bolts are common in the construction and
automotive industries. Eye bolts are threaded at one end and have a
circular eye at the other, instead of a head. The eye is used to guide
a cable, rope or chain for lifting purposes. Eye bolts are common in
aircraft construction. J bolts are also named for their shape, a letter
J, or half of a U bolt. They are used as cast-in-place anchor bolts and
often made of steel or titanium. Stud bolts are round metal bars with
screw threads at both ends or on the whole thing. They have flanges at
a set distance from one end, and used for mounting decorative members.
Expansion bolts consist of a taper-headed bolt, lead sleeve, metal cone
and a nut. They are used to secure theatre, auditorium, stadium and
classroom seating to the floor. They have attachments that expand as
the bolt is driven into a surface. Lag bolts are heavy woodscrews that
have a hexagonal or square head and are usually driven into wooden
beams or posts by a wrench. Hex bolts are named for the number of sides
on their heads-6. They are very common, usually made of metal, and used
with a washer. Finally, shoulder bolts pivot mounting shafts that are
not threaded all the way up-it stops before the head, leaving a
smooth-sided shaft that is usually a little wider than the threaded
part. They can be square or round and are generally made out of
stainless steel. Stainless steel is often chosen for the manufacturing
of bolts because of its strength.