What do the markings on nuts mean?

Bolt heads and nuts are often marked with numbers, letters, dashes, slashes, dots, or an assortment of other marks. Fasteners commonly have two different markings: a unique manufacturer identification symbol – such as letters or an insignia – and information about the fastener strength.

How do you determine the grade of a socket head cap screw?

The first number is the ultimate tensile strength (UTS) in MPa divided by 100 and the second number is the ratio of yield strength to the UTS. Typical bolts are supplied as grade 5.8, 8.8, or 10.9.

How do you read screw specs?

In the Unified Thread Standard (UTS) system, manufacturers list the diameter size as a number between 0 and 10, with 0 being the smallest and 10 being the largest. Screws larger than a #10 have a diameter listed directly in inches. For example, on a #4-40 UNC-3A x . 5 screw, #4 represents the diameter.

Do nuts have grade markings?

Grade A nuts are used with low carbon steel heavy hex bolts. Grade 5 are used with medium carbon cap screws and bolts. Grade C nuts are recommended to be used with A325 structural bolts. Grade 2H nuts are recommended for use in high pressure and high temperature service.

What are the different grades of nuts?

Table 1.

Grade/Class Strength
Grade 2 Low strength.
Grade 2H Nuts Strength is similar to Grade 5. Use with ASTM A325 structural bolts.
Grade 5 Medium strength.
Grade 8 High strength.

Are Grade 8 nuts marked?

Grade 8 nuts shall be marked with six circumferential dashes equally spaced 60° apart. class equal to or higher than class 8 shall be marked on one surface with the class identification number.

What is the difference between a Grade 2 and Grade 8 cap screw?

A grade two hex cap screw is made from medium or low-carbon steel, a grade five consists of medium carbon steel, and a grade eight is made out of medium carbon alloy steel.

What do the markings on a hex head screw mean?

If the cap screw has no markings on the head, it means it is made of low to medium carbon steel. These are the most inexpensive bolts on the market and intended for standard household use. Hex heads with three markings are grade 5 fasteners. This grade is made from medium quality carbon steel. These are commonly used in automotive applications.

What are Grade-8 hex cap screws made of?

Grade-8 hex cap screws are made from medium carbon steel and heat-treated. They have a greater tensile strength than a Grade-5 screw, and designed for use in high stress applications.

What are heavy hex cap screws used for?

These cap screws are good for applications such as docks, piers, boats and boat houses. These cap screws are known as “heavy hex cap screws.” They have a larger head compared to standard hex heads and are shorter in length. A-307B cap screws can be used in many applications, including wood and steel.

What are the different types of hex cap fasteners?

1 A2/Type 304 (18-8) Stainless Hex Cap Grade. Type A304 fasteners are the most commonly used stainless steel fasteners on the market. 2 A4/Type 316 Stainless Hex Cap Grade. A4/316 stainless fasteners are also known as marine grade fasteners due to their ability to withstand the corrosive nature of salt water. 3 A-307B Grade Cap Screw.