Leave Your Message

2024.06.08 Self Drilling Screw / Tapping Screw : ISO category classification C3



Self-drilling screws and tapping screws are typically made from high-quality steel, often carbon steel or stainless steel. They may be coated with zinc or other materials to enhance their corrosion resistance. According to ISO category classification C3, the corrosion rate for zinc coating on these screws is defined between 0.7 and 2.1 µm per year (0.028 and 0.083 mils per year), ensuring long-term durability in various environmental conditions.


Self-drilling screws are designed with a drill point that allows them to drill their own hole and form their own mating thread in one operation. This eliminates the need for pre-drilling, thus saving time and labor. Tapping screws, on the other hand, require a pre-drilled hole but are designed to cut their own threads into the material as they are driven in. Both types of screws provide secure fastening solutions with strong holding power.

Application Scenarios

Self-drilling and tapping screws are versatile and widely used across multiple industries. Common applications include:

  1. Construction: Fastening metal sheets, securing roofing, and assembling steel frames.
  2. Automotive: Attaching metal parts, securing body panels, and other assembly tasks.
  3. Manufacturing: Machinery assembly, electronic enclosures, and appliance manufacturing.
  4. DIY Projects: Home repairs, furniture assembly, and garden structures.


  1. Time Efficiency: Self-drilling screws reduce the need for multiple tools and steps, leading to faster installation.
  2. Cost Savings: By eliminating the need for pre-drilling, labor costs are significantly reduced.
  3. Strong Hold: Both self-drilling and tapping screws provide a robust and reliable fastening, ensuring structural integrity.
  4. Corrosion Resistance: The zinc coating, as classified under ISO C3, provides excellent protection against corrosion, enhancing the longevity of the screws even in moderately corrosive environments.
  5. Versatility: Suitable for a wide range of materials including metals, plastics, and wood, making them highly adaptable to different projects and requirements.


Self-drilling and tapping screws are essential components in various industries due to their efficiency, durability, and versatility. With the added benefit of a zinc coating that adheres to ISO category classification C3, these screws ensure reliable performance and extended lifespan, making them a cost-effective solution for numerous fastening needs.