Definition

Noun: A type of fastener characterized by a square or hexagonal head on one end and a threaded shaft on the other. It is designed to be tightened using a wrench and is primarily used to connect metal parts in machinery and structural applications.

Usage

A machine bolt is a specific, heavy-duty fastener. Its defining features are its wrench-driven head and its fully threaded shank, which distinguish it from similar fasteners like carriage bolts or stove bolts. It is a fundamental component in mechanical assembly.

Examples

• Noun:
  • Secure the steel beam using a high-strength machine bolt.
  • The mechanic replaced the worn machine bolt with a new one from the toolbox.
  • The assembly instructions specify a 3/8-inch machine bolt for this joint.

Advanced Usage

• Specification: Machine bolts are often specified by their material grade (e.g., Grade 5, Grade 8), diameter, thread pitch, and length to ensure they meet the required strength and fit for an application.
  • For this load-bearing connection, you must use a Grade 8 machine bolt.

Variants and Related Words

• Hex Bolt: A very common synonym for a machine bolt with a hexagonal head.
• Hex Cap Screw: A closely related fastener, often considered a higher-precision version of a hex head machine bolt, typically meeting stricter manufacturing standards.
• Carriage Bolt: A different bolt type with a smooth, rounded head and a square section under the head to prevent rotation, used often in wood.

Synonyms

• Hex Bolt
• Hex Head Bolt

Related Phrases

• Machine Screw: A related but distinct fastener; machine screws are generally smaller, have a uniform diameter along the shank, and are designed to be driven into a pre-tapped hole or used with a nut, often tightened with a screwdriver.
  • Unlike a machine bolt, a machine screw typically has a slotted or Phillips head.

Noun

1. a bolt with a square or hexagonal head on one end and a threaded shaft on the other end; tightened with a wrench; used to connect metal parts