hex bolt dimensions

Hex Bolt Dimensions

How To Measure Hex Bolts

Here's a concise overview of the 5 key dimensions associated with metric hex bolts. 

Hex bolts are a common type of fastener known for their hexagonal head and threaded body. Widely used across various applications, from construction and automotive to machinery and electronics, it's crucial to have a good grasp of their metric dimensions when selecting the right fastener for a specific task.

how to measure hex bolts

1. Diameter (W): The diameter of a hex bolt is typically measured across the outer edges of its threads. Common metric sizes range from small diameters, such as 6 mm, to larger diameters exceeding 25 mm. The diameter is a critical factor in determining the bolt's strength and load-carrying capacity.

2. Length (L): The length of a hex bolt is measured from the bottom of the head to the tip of the threaded portion. Hex bolts come in various metric lengths to accommodate different applications, and it's crucial to select a length that allows sufficient engagement with the materials being fastened.

3. Thread Pitch (P): The thread pitch represents the distance between adjacent threads on the bolt. It is measured in millimetres per thread. Coarse thread pitches are common in larger diameter bolts, while fine thread pitches are used in smaller diameter bolts, providing different levels of holding strength.

4. Head Width (S): The hexagonal head width is the distance across opposite flat sides of the bolt head. This dimension is essential for selecting the appropriate metric wrench or socket size for tightening or loosening the bolt. This dimension is measured from flat side to flat side across the bolt head. The term "across flats" is often used to specify the metric wrench or socket size needed to tighten or loosen the bolt.

5. Head Height (D): The head height is the distance from the bottom of the head to the top, including any washer face if present. It contributes to the overall profile of the bolt and may be a consideration when clearance is limited.

Understanding these metric dimensions of bolts is crucial for selecting hex bolts that meet the specific requirements of projects in the UK market. It ensures proper fit, optimal strength, and reliable fastening in a variety of applications.

Here's a video showing how to measure bolts.

Fixabolt offer a wide selection of hex bolts and we strive to have them in stock at all times.

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