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The standard measurement of a fastener:
The important specifications of a fastener are the head type, the diameter of the bolt, thread per pitch of the bolt and the length of the bolt. A fastener is measured by length, diameter and thread count. As small the fastener is, the thread is that much fine. The length of a fastener is measured by shank, excluding the head. Diameter is measured by the breadth of the screw generally from outside. Similarly, the thread count is measured by thread per inch (TPI).
Industrial fastener materials:
According to the industrial standard, the varieties of steel fasteners that are used in the work are stainless steel fastener, carbon steel fastener, and alloy steel fastener. The operating grades of stainless steel fasteners are 200, 300 and 400 series. Other basic materials of fastener construction are Titanium, aluminum and other alloy metals. In some special cases, plating or coating is applied to enhance the performance. Coating of paint adds extra corrosion resistance power to the fastener that provides durability to any construction. Usually, zinc, zinc chrome, cadmium, cadmium dichromate or hot dip galvanising code is used for coating.
While selecting a right fastener, you should know the purpose of the need and the specifics of the application. The list of other considerable factors includes:
Installation process
Accessibility
Materials to be joined
Corrosiveness factor exposed with air, water, temperature and environment
Weight restriction
Reusability
Types of fasteners head:
The shapes of the head of the fasteners are different and they are designed with distinct patterns. The available head patterns of fasteners are such as flat, oval, pan, truss, hex water, slotted hex washer, hex, socket cap, button, round and likewise.
Types of fasteners thread:
The basic varieties of thread are inch based unified coarse or fine and metric coarse or fine. There are certain differences between coarse and fine threads. The density of threads per inch is less in coarse threads than fine threads. They offer better shock resistivity and higher corrosion resistance than fine threads. On the other hand, fine threads are suitable for cross threading assembly. They are 10 % stronger than coarse.
Class or grade of the fastener strength:
The grade or class of a fastener refers to the mechanical strength of the fastener. The higher number in grade indicates the fastener is stronger and fastener. Thereby, the grade 8 fastener is hardest, grade 5 is medium and grade 2 is softer compared to others.
Grade 8 is suitable for heavy unit, industrial or manufacturing requirement. On the other hand, grade 5 is compatible with automobile manufacturing. Grade 2 is generally being used in fastening household units such as screws, machine nuts and likewise.
There are some easy markings that can help to identify the grade of the fastener. Grade 8 consists the minimum of 6 lines on head, while grade 5 has 3 lines on head and grade 2 has no lines.
