Millwright Level 1: Fasteners and Anchors
(15103- 06) Exam Questions and Answers
with Verified Solutions | Latest Updated 2026
Fasteners Used to assemble and install many
different types
of equipment, parts, and materials.
Fasteners
include screws, bolts, nuts, pins, clamps,
retainers,
tie wraps, rivets, and keys.
Threaded Fasteners Threaded fasteners are the most
commonly used
type of fastener. Many threaded fasteners
are
assembled with nuts and washers.
,Thread Standards There are many different types of threads
used for
manufacturing fasteners. Threads used on
fasteners
are manufactured to industry-established
standards for uniformity. The most
common thread
standard is the unified standard,
sometimes
referred to as the American Standard.
Unified
standards are used to establish thread
series and
thread class.
Thread Series Unified standards are established for three
series
of threads, depending on the number of
threads
per inch for certain diameter of fasteners.
Unified National Coarse (UNC) Used for bolts, screws, nuts and other
Thread general
purposes. Fasteners with UNC threads are
commonly used for rapid assembly or
disassembly
of parts and where corrosion or slight
damage may
occur.
Unified National Fine (UNF) Used for bolts, screws, nuts, and other
Thread applications
where a finer thread for a tighter fit is
desired.
, Unified National Extra Fine Used on thin-walled tubes, buts, ferrules,
(UNEF) and
Thread couplings.
Thread Classes The Unified standards also established
thread
classes. Classes 1A, 2A, and 3A apply to
external
threads. Classes 1B, 2B, and 3B apply to
internal
threads. Thread classes are distinguished
from each
other by the amounts of tolerance
provided.
-Classes 1A and 1B provide a maximum
clearance,
used where quick and easy assembly is
needed
and a large tolerance is acceptable.
-Classes 2A and 2B are the most
commonly used.
-Classes 3A and 3B provide a minimum
clearance,
used when close tolerances are needed.
Thread Identification Standard symbols used to identify threads.
Nominal size The approximate diameter of the fastener.
Number of threads per inch (TPI) The TPI is standard for all diameters.
(15103- 06) Exam Questions and Answers
with Verified Solutions | Latest Updated 2026
Fasteners Used to assemble and install many
different types
of equipment, parts, and materials.
Fasteners
include screws, bolts, nuts, pins, clamps,
retainers,
tie wraps, rivets, and keys.
Threaded Fasteners Threaded fasteners are the most
commonly used
type of fastener. Many threaded fasteners
are
assembled with nuts and washers.
,Thread Standards There are many different types of threads
used for
manufacturing fasteners. Threads used on
fasteners
are manufactured to industry-established
standards for uniformity. The most
common thread
standard is the unified standard,
sometimes
referred to as the American Standard.
Unified
standards are used to establish thread
series and
thread class.
Thread Series Unified standards are established for three
series
of threads, depending on the number of
threads
per inch for certain diameter of fasteners.
Unified National Coarse (UNC) Used for bolts, screws, nuts and other
Thread general
purposes. Fasteners with UNC threads are
commonly used for rapid assembly or
disassembly
of parts and where corrosion or slight
damage may
occur.
Unified National Fine (UNF) Used for bolts, screws, nuts, and other
Thread applications
where a finer thread for a tighter fit is
desired.
, Unified National Extra Fine Used on thin-walled tubes, buts, ferrules,
(UNEF) and
Thread couplings.
Thread Classes The Unified standards also established
thread
classes. Classes 1A, 2A, and 3A apply to
external
threads. Classes 1B, 2B, and 3B apply to
internal
threads. Thread classes are distinguished
from each
other by the amounts of tolerance
provided.
-Classes 1A and 1B provide a maximum
clearance,
used where quick and easy assembly is
needed
and a large tolerance is acceptable.
-Classes 2A and 2B are the most
commonly used.
-Classes 3A and 3B provide a minimum
clearance,
used when close tolerances are needed.
Thread Identification Standard symbols used to identify threads.
Nominal size The approximate diameter of the fastener.
Number of threads per inch (TPI) The TPI is standard for all diameters.
