How can you tell if a bolt is high tensile?

They both use numbers to grade their bolts – the higher the number, the higher the tensile strength. For instance, the SAE system covers diameters of up to 1 ½ inch, and a grade 8 would have a higher tensile strength than a grade 5.

What do the symbols on top of bolts mean?

You can usually figure out the grade, or strength, of a bolt by looking at the markings on its head. English bolts (U.S.S. or S.A.E) are categorized by grade, from grade 2 to grade 8, where the grade represents inch strength. The higher the grade, the stronger the bolt.

How do I identify my bolt manufacturer?

Manufacturer’s identification mark, e.g., “X” ( on head of bolts and screws and on one end of studs and stud bolts). Manufacture’s identification mark, e.g., “X”, applied to head (raised or depressed at option of manufacturer).

Why are high tensile bolts black?

Fastener Black oxide is a common method for chemically anti-rusting the surface of fasteners.

What are bolt grade markings?

The grade of a bolt determines the maximum amount of stress (tensile strength) that the bolt can handle. Tensile strength is the amount of pull the bolt can withstand before breaking. The method used for tightening the bolt is also dependent upon the grade of the bolt.

What is the meaning of letter A in the bolt coding?

For example, in the bolt part number AN3DD5A, the “AN” designates that it is an Air Force-Navy Standard bolt, the “3” indicates the diameter in sixteenths of an inch (3/16), the “DD” indicates the material is 2024 aluminum alloy.

What do black bolts mean?

The term “black bolt” is an industry term for plain finish or no finish bolts. These bolts offer no corrosion resistance and will rust over time.

What’s the difference between black and silver bolts?

What is the difference between the black and the silver bolts? The black bolts you are sent are A325 bolts and the silver bolts are A307 bolts. A325 bolts are much stronger and are used in conections that require more strength.