Overview of Fasteners 115

This class describes common types of threaded and non-threaded fasteners as well as their components and applications.

Class Details

Class Name:
Overview of Fasteners 115
Number of Lessons:
Additional Language:

Class Outline

  • Objectives
  • What Is a Mechanical Fastener?
  • Threaded and Non-Threaded Fasteners
  • Types of Threaded Fasteners
  • Bolts
  • Parts of a Bolt
  • Types of Bolts
  • Screws
  • Types of Screws
  • Nuts
  • Types of Non-Threaded Fasteners
  • Semi-Permanent Pins
  • Quick-Release Pins
  • Retaining Rings
  • Types of Retaining Rings
  • Rivets
  • Pros and Cons of Riveting
  • Washers
  • Summary


  • Define mechanical fastener.
  • Distinguish between threaded and non-threaded fasteners.
  • List common types of threaded fasteners.
  • Describe characteristics of bolts.
  • Identify the parts of a bolt.
  • Describe common types of bolts.
  • Describe characteristics of screws.
  • Describe common types of screws.
  • Describe characteristics of nuts.
  • List common types of non-threaded fasteners.
  • Describe types of semi-permanent pins.
  • Describe types of quick-release pins.
  • Describe characteristics of retaining rings.
  • Describe types of retaining rings.
  • Describe characteristics of rivets.
  • Describe the pros and cons of riveting.
  • Describe characteristics of washers.

Job Roles



Vocabulary Term Definition
adhesive bonding The joining of two or more materials through the use of adhesives such as liquids, drops, or gels.
axially assembled ring A type of retaining ring that is installed parallel to the axis of the shaft or bore in which the ring will be used.
bearing surface The circular underside of the bolt head that makes contact with the part.
blind rivet A type of rivet with a tubular shank that is installed from one side of the part. Blind rivets are generally used to simplify assembly and to improve appearance.
blind threaded hole A type of hole that does not go completely through the material. Most screws are assembled into blind threaded holes.
bolt A cylindrically shaped, threaded device used for fastening parts. Bolts usually have blunt ends and mate with a nut.
bolt head The enlarged shape formed on one end of the bolt. The type of bolt head determines the type of tool used to tighten it.
bore The internal surface of a cylinder. Bore surfaces are often accurately ground to accommodate a retaining ring with minimum friction.
burr An irregular, rounded mass on an object.
capscrew A type of screw often used in tapped holes. Capscrews are very similar to machine screws, but they are often made with higher-strength material and to closer tolerances.
clamping force The compressive force that a fastener exerts on a joint.
clevis pin A type of semi-permanent pin used to connect a yoke, fork, or eye assemblies in swivel or knuckle-type joints. Clevis pins are usually held in place by cotter pins.
coarse thread A thick thread.
collar A coupling device with internal threads designed to attach to another part.
corrosion resistance The ability to resist a chemical attack on a material by atmosphere, moisture, or other agents.
cotter pin A semi-permanent pin that fits through a hole in a nut to lock it in place. Cotter pins are generally used when great accuracy is not required.
deformable To become misshapen when subjected to a type of force.
detent mechanism A device that positions and holds one part in relation to another so that the device can be released by the force applied to one of the parts.
driving recess The shape on the top of a fastener head designed to accept a driving tool. A screwdriver is an example of a driving tool.
external thread A type of thread formed on the outside of a cylinder, such as on bolts and screws.
external-type ring A retaining ring that fits over a shaft or pin.
flat washer A type of washer that is slighly oversized allowing it to slide easily over the bolt.
friction The resistance between the contact surfaces of two objects.
gear A mechanism for transmitting motion for a specific purpose.
grade A category, rank, or level of quality. Bolts are classified by grades.
grip length The length of the unthreaded portion of the bolt shank.
hex bolt A type of bolt that has a head with six sides.
hexagon-head capscrew A type of capscrew with a six-sided head. Hexagon-head capscrews are the most common screws in use.
housing A protective cover designed to contain or support a mechanical component.
interference fit An amount of overlap between two objects.
internal thread A type of thread formed in holes, such as in nuts.
internal-type ring A retaining ring that fits into a bore or housing.
large rivet A type of rivet with a solid shank and a diameter of 0.500 in. or more. Large rivets are mainly used for structural work on buildings, bridges, or tanks.
load The amount of force placed upon an object. Bolts must remain tight under loads.
lock washer A type of washer used under the head of a bolt or nut to grip the fastener to the part's surface.
locking lug A type of detent mechanism on a push-pull pin.
locking nut A type of nut that contains a locking element that engages the base surface and creates a tight friction grip against the bolt threads.
machine screw A type of screw that assembles into tapped holes or nuts. Machine screws are the most general types of screws and are very similar to bolts.
major thread diameter The distance between the crests of a thread. Major diameter is the widest diameter on a thread.
mechanical fastener A device that holds two or more objects together. A fastener can be a button or a zipper as well as a bolt or a screw.
milling machine A machine that uses a multi-point tool to remove metal from the surface of a workpiece.
non-threaded fastener A type of fastener that does not contain threads. Common types of non-threaded fasteners include pins, retaining rings, and rivets.
nut A block, usually made of metal, with a threaded hole that mates with a bolt. The outer shape of a nut is often six-sided.
pin A thin, often straight, cylindrical non-threaded fastener used to secure the position of two or more machine parts.
plain nut A type of nut that does not provide a self-locking action.
plain washer Another name for a flat washer.
plow bolt A square-head bolt often used on heavy construction equipment.
point The extreme end of the threaded portion of the bolt. The point comes in a variety of shapes.
positive-locking pin A quick-release pin that has an independent locking action. Positive-locking pins are ideal for quick-change operations.
push-pull pin A quick-release pin with a solid shank and a detent mechanism backed up by a spring or plug.
quick-change operation A type of operation in which someone is able to prepare the machine to run another size or type of product quickly.
quick-release pin A type of pin that is generally used for the manual assembly and disassembly of rigid machine components. Quick-release pins include push-pull pins and positive-locking pins.
radially assembled ring A type of retaining ring that contains side openings that permit the rings to be placed directly into the groove on the shaft.
residual stress A type of internal stress that results from cold working, forming, or other means.
retaining ring A type of non-threaded fastener that provides a removable shoulder to accurately locate or lock parts on shafts, bores, or housings.
right-hand thread A type of thread that is screwed in by rotating it clockwise.
rivet A type of non-threaded fastener that consists of a shank and a head made of deformable material. Rivets are inserted through holes and are hammered into a matching head on the other side of the part.
riveting A fastening process using rivets.
screw A threaded device used for fastening parts or transferring motion. Screws usually have pointed ends.
self-locking ring A type of retaining ring that serves mainly as a positioning and locking device.
self-tapping screw A type of screw that forms or cuts threads in materials without pre-tapped holes.
semi-permanent pin A type of pin that requires pressure, force, or tools for installation or removal. Semi-permanent pins include straight pins, taper pins, cotter pins, and clevis pins.
setscrew A type of screw, often with no head, used to hold a sleeve, collar, or gear on a shaft to prevent motion.
shank The cylindrical part of the bolt that extends from the underside of the head to the point.
shoulder The part on a retaining ring that positions or limits the movements of parts in an assembly.
sleeve A tubular part designed to fit over another part.
small rivet A type of rivet with a shank diameter of less than 0.500 of an inch. Small rivets are often used in the sheet metal and aircraft industries.
snap ring Another name for retaining ring.
socket-head capscrew A type of capscrew with a round head and a hexagonal indentation for tightening purposes. Socket-head capscrews are effective in confined spaces where small head size is required.
spring steel A type of steel, generally made with high carbon, that has high tensile properties.
square-head bolt A type of bolt with a square-shaped head and a larger bearing surface. Square-head bolts are often used in wooden assemblies and farm machinery.
straight pin A solid, cylindrical semi-permanent pin mainly used to locate machine parts in a fixed position or to maintain alignment. Straight pins are the most basic pins.
structural bolt A heavy type of hex bolt intended for use in large structures, such as buildings and bridges.
taper pin A semi-permanent pin that has a 1/4 inch-per-foot taper on its diameter. Taper pins are often used on parts that require frequent assembly and disassembly.
tapered fit A type of fit in which the diameter of the fastener gradually decreases to fit into a mating hole.
tapped hole A type of hole that contains internal threads created by forming or cutting.
tensile strength The ability of a material to resist forces that attempt to pull it apart or stretch it.
T-head bolt A type of bolt with a head in the shape of the letter "T." T-head bolts are often inserted into T-slots on the bed of a machine tool.
thread gage A measuring instrument used to inspect the internal or external threads of a part.
thread length The length of the threaded portion of the bolt shank.
thread-cutting screw A type of screw that has cutting edges and produces a mating thread by removing material from the engaged section.
threaded fastener A type of fastener that contains threads. Bolts, screws, and nuts are examples of threaded fasteners.
thread-forming screw A type of screw that forms the material around a hole until it wraps around the screw threads. Thread-forming screws do not remove any material from the engaged section.
tolerance The unwanted but acceptable deviation from the desired dimension.
torque The amount of force applied to tighten a threaded fastener.
T-slot An opening in the shape of the letter "T," which can accommodate a T-head bolt.
twelve-point bolt A type of bolt with a double hexagon head and a low weight-to-strength ratio. Twelve-point bolts are high-strength fasteners often used in the aircraft industry.
washer A flat disc with a hole through the center that is often used with threaded fasteners to ensure tightness of the joint.
weight-to-strength ratio The weight of an object divided by its strength. Twelve-point bolts have a low weight-to-strength ratio.
welding A joining process that uses heat, pressure, and/or chemicals to fuse two materials together permanently.
wood screw A type of screw with a sharp, pointed end and a tapered shank with sharp threads for penetrating wood. Wood screws come in a variety of styles.
wrench A tool used to hold or twist nuts and bolts.