Tough Fasteners Guide

When it comes to selecting a tough fastener, many factors require consideration. With virtually endless configurations available, YOU can choose the right part for your connection at a cost that works for you. The “toughness” of your fastener depends on several key factors—let’s break it down!

GRADE: In the fastener industry, there are established oversight bodies including ASTM, ISO, SAE, DIN, and ANSI that define universal standards, ensuring consistency across manufacturers. This means that no matter where a fastener comes from, you can trust its specifications. One critical element that remains consistent is the fastener grade. The grade indicates the strength and material properties of the fastener and gives you a sense of how much load it can handle before failure. The higher the grade, the stronger the fastener. Let’s review hex cap screws as an example:

• Grade 2- 60,000psi tensile strength
  • Great option for general purpose applications with less demanding needs where strength isn’t a priority
• Grade 5/Metric Class 8.8- 120,000psi tensile strength
  • These screws are suitable for automotive, machinery, or manufacturing applications providing reliability for moderate tasks.
• Grade 8//Metric Class 10.9- 150,000psi tensile strength
  • Best for high reliability under extreme conditions such as in heavy machinery or construction.

MATERIAL: The materials selected for manufacturing fasteners play a vital role in determining their performance across a range of conditions. The choice of material significantly influences the fastener's strength, durability, corrosion resistance, and overall cost-effectiveness. Additionally, it is essential to assess the environmental factors specific to the application, as these will directly impact the long-term efficacy and reliability of the fastener.

• Steel: One of the most common materials, steel offers excellent tensile strength and is typically used in general-purpose fasteners. It’s available in different grades with additional elements (such as chromium or nickel) to further increase strength and durability. Given that its widely available, steel fasteners are a cost-effective option for most applications. However, plain steel is not able to withstand moisture or similar environmental conditions resulting in a decreased longevity than those applications indoors for instance. (Stay tuned for discussions about how plating can impact steel!)
• Brass: Corrosion-resistant and non-magnetic, brass is often used in applications where aesthetics are a higher priority (such as architectural or decorative designs). It is often called for in electrical components because of its conductive properties as well. Brass is suitable for low temperature applications as it will become brittle with high heat or chemical exposure making it less reliable than steel and stainless steel.
• Stainless Steel: Known for its excellent resistance to rust and corrosion, stainless steel is ideal for those applications with moisture, chemical, or other harsh environmental considerations exist. It also can withstand moderate to high temperature applications making it an excellent choice for exposure to heat. These factors allow stainless steel greater longevity in harsh environments, which comes with a higher cost than steel. Depending on your application, the initial higher cost is worth the increased maintenance cost of lesser materials.

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