Wrenches, also known as spanners, are hand-held tools designed to provide a mechanical advantage in applying torque for turning bolts, nuts, and other wrench-friendly objects. Wrench is a standard term, whereas spanner refers to a specialized wrench with a series of pins or tabs around the circumference.

Wrenches enable the application of a large amount of torque from a force generated by a user’s hand through the principle of mechanical advantage. The torque of wrenches is applied to the head of a bolt, nut, or other object through turning of the wrench handle in a direction perpendicular to the bolt, nut, or object. This increased amount of torque enables the bolt, nut, or object to easily thread together or thread into a material. High-quality wrenches are typically made from chromium-vanadium alloy steels and are often drop-forged. Wrenches are frequently chrome-plated for corrosion resistance.

Types of Wrenches

There are a variety of types of wrenches including:

• Adjustable wrenches
• Box wrenches
• Chain wrenches
• Combination wrenches
• Crowfoot wrenches
• Dog bone wrenches
• Flare-nut wrenches
• Key wrenches
• Lock wrenches
• Lug wrenches
• Single end wrenches
• Socket wrenches
• Spanner wrenches
• Spud wrenches
• Strap wrenches
• Torque wrenches

Video credit: Norbar Torque / CC BY-SA 4.0

Hinged tools, such as pliers or tongs, are not generally considered for the same purpose as wrenches. Wrenches for screws and bolts with internal sockets are generally referred as ‘keys’ in Europe. Other common and widely used wrenches are termed as pipe wrenches, or Stillson wrenches. These types of wrenches are adjustable and used for turning soft iron pipes and fittings with a rounded surface. The design of the adjustable jaws allow these wrenches to rock in the frame, such that any forward pressure on the handle tends to pull the jaws tighter together.

Special types of wrenches include angled-drive wrenches, offset drive wrenches, flex drive wrenches, jaw scale wrenches, and ratcheting soft grip handle wrenches. High-polish chrome wrenches are easier to clean than matte-finish wrenches. Manufacturers may offer storage trays or pouches for easy storage and organization. Typically, some companies provide a lifetime warranty on their wrenches.

Applications

Wrenches have wide applications in assemblies, plumbing, construction, and automotive sectors for maintenance, repair, and operations.

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