Tools for Threaded Fasteners 235

The class Tools for Threaded Fasteners provides a comprehensive overview of the different tools that are used to assemble threaded fasteners. There are many different types of tools used with threaded fasteners, but they all operate by applying torque. Manually powered hand tools include wrenches and screwdrivers. Power tools include battery-operated tools, electric tools, and pneumatic tools. Many power tools use clutches to control operation. These may be continuous-drive tools or discontinuous-drive tools.

Threaded fasteners are the most commonly used fasteners in assembly, and assemblers must be familiar with the different tools they require. After taking this class, users will have foundational knowledge of the different types of tools used with threaded fasteners and their advantages and disadvantages. Users will also be able to identify some of the factors that go into selecting a tool for a threaded fastener application.

  • Difficulty Intermediate

  • Format Online

  • Number of Lessons 19

  • Language English


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Course Outline
  • Threaded Fastener Tool Selection
  • Types of Fastening Tools
  • Hard Joints and Soft Joints
  • Tool Ergonomics
  • Review: Tool Selection
  • Hand Tools
  • Types of Wrenches
  • Types of Screwdrivers
  • Review: Hand Tools
  • Battery-Powered Tools
  • Electric Tools
  • Pneumatic Tools
  • Review: Power Tools
  • Clutch Operation
  • Continuous-Drive Tools
  • Types of Continuous-Drive Tools
  • Discontinuous-Drive Tools
  • Types of Discontinuous-Drive Tools
  • Review: Continuous- and Discontinuous-Drive Tools
  • Describe threaded fastener tools and selection factors.
  • Distinguish between different types of tools for threaded fasteners.
  • Distinguish between hard and soft joints.
  • Describe ergonomics for fastening tools.
  • Describe common hand tools.
  • Distinguish between common wrenches.
  • Distinguish between common screwdrivers.
  • Describe battery-powered tools.
  • Describe electric tools.
  • Describe pneumatic tools.
  • Define clutch.
  • Describe continuous-drive tools.
  • Distinguish between common continuous-drive tools.
  • Describe discontinuous-drive tools.
  • Distinguish between common discontinuous-drive tools.
Vocabulary Term

air dryers

A device that extracts moisture from the air. Air dryers are often required to prepare air for use in pneumatic systems.

assembly line

An arrangement of workstations used to mass produce products in stages. Assembly lines may produce a single model or multiple models of the same product.

automatic-shutoff screwdriver

A screwdriving tool that uses a continuous-drive clutch and shuts off when it reaches torque. Automatic-shutoff screwdrivers are used for repetitive, precise applications.


A flexible, retractable line of rope or wire used to suspend tools over workstations. Balancers help create ergonomic workstations.

base component

A material or object being joined by fasteners. Base component materials affect the amount of torque required to properly install threaded fasteners.

battery-powered tools

A tool powered by a battery. Battery-powered tools are the most portable of all the power tools used for fastening.


A cylindrical threaded fastener with a head that usually mates with a nut. Bolts typically have blunt ends.

box wrench

A wrench with a closed, circular end that surrounds a nut or bolt head completely. Box wrenches may have six- or twelve-point openings.


A mechanism found inside a motorized device that connects and disconnects parts to drive the device. A clutch is used to control the operation of many power tools used for fastening.

combination wrench

A wrench with one open end and one box end. Combination wrench ends are typically the same size.

continuous-drive clutch

A type of clutch that delivers power to the tool constantly. Continuous-drive clutches are used mainly with soft joints and high torque.


An imperfection in a part that prevents it from operating correctly. Defects can lead to reworked or scrapped parts, which increases the cost of a manufacturing operation.

direct-drive screwdriver

A screwdriving tool that uses a continuous-drive clutch and stalls when it experiences load resistance. Direct-drive screwdrivers are typically used for applications that do not have precise torque requirements.

discontinuous-drive clutch

A type of clutch that delivers power to the tool in bursts. Discontinuous-drive clutches are used mainly on harder joints.

distribution system

A network of electrical components that provides electricity from the utility to specific end destinations. A distribution system uses generators, power lines, and transformers to deliver electric power to buildings and other structures.

driving recess

The indentation on top of a fastener head. The driving recess is designed to accept a matching driving tool.

duty cycle

The length of time a tool can perform work before it must rest to prevent it from overheating. Duty cycle may limit the productivity of electric tools.

electric tools

A tool powered by electricity supplied by an electrical distribution system. Electric tools operate quietly and cleanly.


The scientific study of equipment, workspace, and production environment design to increase comfort, safety, and productivity. Ergonomic concerns influence tool selection.

flat-blade screwdriver

A screwdriver with a flat tip that corresponds to slotted screws. A flat-blade screwdriver is sometimes referred to as a slotted screwdriver.


A round or cylindrical mechanical component with teeth that is used to transmit power. Gears are designed to mesh with each other to alter the speed, torque, or direction of mechanical energy.

hand tools

A tool that is powered by an operator's manual force. The most common hand tools for threaded fasteners are wrenches and screwdrivers.

hard joint

A joint formed by base components made of harder, more resistive materials, such as metal. A hard joint requires a snug-tight fastener to turn less than 30° to reach torque.


The end of a fastener that provides a surface for gripping and turning and allows it to bear loads. Head shape and size determines the type of tool used to turn the fastener.

hydraulic power

Energy derived from the movement of liquids, such as oil or water. Hydraulic power is used to generate torque for pulse tools.

impact wrench

A tool that uses a discontinuous-drive clutch and mechanical power to produce torque. Impact wrenches are often used to tighten lug nuts on cars.


The part of an open-end wrench that grips bolts or nuts. Jaws can be fixed or adjustable.


The point at which two materials are attached or joined together. Most fasteners create a joint that can be disassembled and reassembled.


Force or pressure placed on an object. The load on a fastening tool may affect its operation.

lug nuts

A large nut that mates with a heavy bolt. Lug nuts are commonly used on car tires.

mechanical power

Energy derived from the physical interaction and motion of components. Mechanical power is used to generate torque for impact wrenches.


A specific design of a product. Different models of the same product may require different fastening tools.

moving assembly lines

An assembly line in which large products, like cars or airplanes, move slowly through the workstations while assemblers work on them. Moving assembly lines often use battery-powered fastening tools.


A fastener with a threaded hole that mates with a bolt. Nuts are often six-sided to accommodate a tool.

open-end wrench

A wrench that contains a set of jaws that fit around a nut or bolt head. Open-end wrenches are ideal for use when the bolt or nut is not easily accessible.

Phillips screwdriver

A screwdriver with a four-pointed, cross-shaped tip that corresponds to Phillips screws. Phillips screwdrivers are sometimes confused with Pozidriv screwdrivers.

pistol grip

A curved tool-handle grip that is designed to fit with the anatomy of the hand. A pistol grip should be used for horizontal joints.

pneumatic tools

A tool powered by compressed air. Pneumatic tools are good for repetitive fastening tasks and for applications with high torque requirements.

power source

A device used to generate the energy needed to power a tool. The most common power sources for fastening tools are batteries, electrical systems, and compressed air.

power tools

A tool that is powered by an external source of energy. Power tools for fastening are commonly powered by batteries, electrical systems, and compressed air.

power-to-weight ratio

The power a tool generates divided by the weight of the tool. High power-to-weight ratios are preferable.

Pozidriv screwdriver

A screwdriver with an eight-pointed tip that corresponds to Pozidriv screws. Pozidriv screwdrivers are sometimes confused with Phillips screwdrivers.


The amount of tension a fastener experiences after reaching the proper torque value. Preload tension creates the force that holds a joint together.

pulse tool

A tool that uses a discontinuous-drive clutch and hydraulics to generate torque. Pulse tools are common for applications that use large bolts.


A wrenching device attached to a socket that turns a fastener in one direction only. Ratchets allow for easy installation because they do not need to be repositioned.


A tool used to tighten and loosen screws. Screwdrivers have a handle on one end and a blade on the other end that fits into the recess in the head on a corresponding screw.


A cylindrical threaded fastener that either fits into a threaded hole or forms threads in a material. Screws may have blunt or pointed ends.

slip-clutch screwdriver

A screwdriving tool that uses a continuous-drive clutch that disengages the motor once it achieves torque. Slip-clutch screwdrivers are versatile and convenient for applications that require a variety of fastener and joint types.

snug tight

Assembled with mild manual pressure. Once snug tight, a fastener must be torqued for the joint to be properly assembled.


A hollow device that covers a nut or bolt head completely and attaches to a wrenching device. Sockets come in sets of different sizes with compatible wrenching devices.

socket wrench

A wrench that consists of a handle-like device with an interchangeable round attachment called a socket that completely covers the nut or bolt head. Socket wrenches can use ratchets, T-handles, and extensions to turn fasteners.

socket wrench set

A set of tools that includes various sockets and wrenching devices that can be attached to the sockets for tightening. Socket wrench sets generally include T-handles and ratchets.

soft joint

A joint formed by base components made of less resistive materials, such as plastic. A soft joint requires a snug-tight fastener to turn more than 720&deg, or two full rotations, to reach torque.


To stop running, typically because of an overload. Meeting load resistance causes a motor to stall.

straight handle

A cylindrical tool-handle grip. A straight handle should be used for vertical joints.


A wrenching device in the shape of a "T" that attaches to a socket. T-handles contain a mechanism that prevents over-torquing.

threaded fasteners

A type of fastener that contains threads. Bolts, screws, and nuts are examples of threaded fasteners.


A force that causes rotation. Torque is required to tighten a bolt, screw, or nut.

torque reaction

A jerk that assemblers feel in the handle of the tool they are using when torque is reached. Torque reaction is undesirable and is an ergonomic concern because it can cause injury.

torque regulator

A mechanism found on some threaded fastener tools that controls torque by stopping the tool from rotating once the specified value is reached. Torque regulators help assemblers reach torque requirements accurately.

torque tools

A tool with specialized features that ensure greater torque accuracy. Torque tools provide a reading that indicates applied torque or have a mechanism that stops rotation when torque is reached.

torque wrenches

A tool used to apply a specific amount of torque to a bolt or nut. Torque wrenches are usually socket wrenches with special internal mechanisms.

Torx screwdriver

A screwdriver with a six-pointed tip that corresponds to Torx screws. Torx screwdrivers exert higher torque without damaging the screw or driver.


A tool used to tighten and loosen bolts and nuts. Wrenches contain fixed or moving jaws or a round attachment that grips nuts and bolts.