Hexagonal bolts are used to fasten metal parts together.  They are commonly used in construction, machinery and automotive applications.  The bolt’s hex head allows for easy tightening and loosening with a wrench or socket, making it a popular choice for securing heavy components.

To measure a metric bolt, you need to determine the diameter, pitch, and length.

1. Diameter: Use a caliper to measure the diameter of the bolt. For example, if it is an M20 bolt, the diameter is 20mm.

2. Thread pitch: Use a pitch gauge to measure the distance between threads. This will help you determine the thread pitch, which is critical for matching the bolt to the correct nut.

3. Length: Use a ruler or tape measure to measure the length of the bolt from the bottom of the head to the tip.

By accurately measuring these three aspects, you can identify and select the right metric bolt for your specific application.

 ”TPI” stands for “threads per inch.”  It is a measurement used to indicate the number of threads present in a one-inch bolt or screw.  TPI is an important specification to consider when matching bolts to nuts or determining threaded component compatibility.  For example, an 8 TPI bolt means that the bolt has 8 complete threads in one inch.

To determine whether a bolt is metric or imperial, you can follow these general guidelines:

1. Measuring system: Check the markings on the bolts. Metric bolts are usually marked with the letter “M” followed by a number, such as M6, M8, M10, etc., indicating the diameter in millimeters. Imperial bolts are usually marked with a fraction or number followed by “UNC” (Unified National Coarse) or “UNF” (Unified National Fine), indicating the thread standard.

2. Thread pitch: Measures the distance between threads. If the measurement is in millimeters, it’s most likely a metric bolt. If the measurement is in threads per inch (TPI), it’s most likely an imperial bolt.

3. Head markings: Some bolts may have markings on their heads to indicate their grade or standard. For example, metric bolts may have markings such as 8.8, 10.9, or 12.9, while imperial bolts may have markings such as “S” or other grade markings for structural bolts.

By considering these factors, you can determine whether a bolt is metric or imperial.