How do you read a bolt part number?

If a bolt is longer than an inch the first digit is the number of inches and the second digit is the number of eighths. For example: AN3-12 is a bolt with 3/16 inch diameter and the length is 1 inch plus 2/8 or 1-1/4 inch long.

What do the numbers on bolts mean?

The first number in each size is the nominal or root (minor) diameter (mm) and the second number is the thread pitch (mm). NOTE: Remember that the nominal bolt diameter is the measurement of the bolt diameter as taken from the bottom of the threads NOT the top (which would be major diameter).

How do I identify a bolt?

Fasteners are identified by four or five attributes; Type, Material, Diameter, Length, and Thread Pitch or Count (machine thread fasteners only).

What do 3 lines on a bolt head mean?

The markings can identify the standard to which the bolt was made. For instance, if a bolt head contains three radial lines, then it’s a Grade 5 bolt. If it contains five radial lines, then the bolt is Grade 8.

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What grade is a bolt with 3 markings?

Three radial lines will indicate an SAE grade 5 fastener, while six radial lines will indicate an SAE grade 8 fastener.

How do you measure a bolt hole?

To determine the bolt size with the help of the measurement scale, you have to place the bolt scale on top of the hole you want to measure. The scales with bolt threads come with many bolts on them. It is arranged according to the shape and also the number of the bolt size.

What are the markings on a bolt head?

The higher the grade, the stronger the bolt. English bolts have radial lines on their head to identify the grade, or strength class. The number of lines on the bolt head is 2 less than the actual grade. So, for example, a grade 5 bolt will only have 3 radial lines on its head.

What does the 8.8 on a bolt mean?

If you have ever looked a metric hex bolt you might notice the markings 8.8, 10.9 or 12.9 this does not mean grade 8,10 or 12. The grade 8.8 refers to the tensile strength which is generally 116,000 psi, grade 10.9 is generally 150,000 and grade 12.9 is generally 175,000 psi.

How do I know if my bolts are standard or metric?

For both metric and standard bolts, the head size is the distance across the flats. For standard bolts, the head size is measured in inches or fractions of an inch. For metric bolts, head size is measured in millimeters. However, metric bolt head size is measured in millimeters.

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How do I know if my bolts are metric or standard?

Telling the difference between a metric and imperial bolt is easy. If the bolt has lines on the head its standard or imperial. If the bolt has numbers on the head then its metric.

How do I know if I have a M8 bolt?

The defined diameter of metric bolts is actually slightly larger than the actual diameter of the bolt shaft. So an M8 bolt would have a shaft diameter that’s slightly under 8mm which means that the bolt should fit through an 8mm hole.

How do you determine if you are using the correct type of bolts and nut in a certain part of an aircraft?

Identification and Coding

AN-type aircraft bolts can be identified by the code markings on the bolt heads. The markings generally denote the bolt manufacturer, the material of which the bolt is made, and whether the bolt is a standard AN-type or a special purpose bolt.

How are bolts and nuts measured?

How to Measure Nuts & Bolts

  1. Place the head of a bolt or a nut into a nut and bolt gauge. …
  2. Measure the shank length of the bolt from the bottom of the head (where it meets the shank) to the bottom of the bolt, using a measuring tape to determine its overall length.