Understanding Common Types of Fastener Screws — Presented by ASM Fastener China

2025-10-31 09:28:07

Fasteners are an indispensable part of modern industry and daily life. From machinery and construction to shipbuilding and petrochemical projects, every connection relies on the reliability of screws, bolts, and nuts. Among the many types, self-tapping screws, wall board screws, self-drilling screws, wood screws, and machine screws are some of the most widely used. Today, ASM Fastener China will introduce these screw types and their main characteristics.

1. Self-Tapping Screws

Self-tapping screws are designed to form their own threads as they are driven into materials such as metal or plastic.
Reference Standards: ANSI/ASME B18.6.4 (inch series), GB845, GB846, JIS B1122, DIN7971–7983, ISO1479–1483, ISO7049–7051 (metric series).
Head Types: Round head, countersunk head, and pan head are most common, depending on application and region.

These screws are ideal for light metal or thin sheet applications where pre-tapping is not economical.

2. Wall Board Screws

Wall board screws are mainly used for fastening drywall or gypsum board to metal or wooden frames.
Reference Standards: JIS B1125, GB/T 14210-93C, or customer-specific requirements.
Head Types: Trumpet head (DW) is the most common, while large washer head (TW) and wafer head (AF) are also used.

They are available in fine-thread and coarse-thread versions — fine thread for metal studs, coarse thread for wood. The typical thread angle is 60°, with a point angle around 25° ±3°.

3. Self-Drilling Screws

Self-drilling screws combine drilling, tapping, and fastening in one operation, saving installation time.
Reference Standards: ANSI/ASME B18.6.4, DIN7504.
Head Types: Hex washer head, pan head, and flat head.
Thread Types: BD (similar to AB thread for self-tapping screws) and CD (machine screw thread).
Length: Screws up to 1-1/2 inch are fully threaded; above 1-1/2 inch, they are partially threaded.

These screws are especially common in steel structures, sheet-metal fabrication, and HVAC systems.

4. Wood Screws (Chipboard / Fiberboard Screws)

Wood screws are designed for fastening wood-based materials such as plywood, MDF, or chipboard.
Standards: According to customer specifications.
Head Types: Flat head, pan head, or large washer head.
Drive Types: Cross (Phillips) and Torx are most common.

The thread design typically has a 40° flank angle, providing excellent self-locking ability and smooth insertion without cracking the wood. Clean thread roots are essential to prevent breakage or rust during use.

5. Machine Screws

Machine screws are precision fasteners designed for mechanical assemblies and equipment connections.
Reference Standards:

• Metric: GB65–GB820 series, DIN963–DIN966, JIS B1111

• Inch: ANSI/ASME B18.6.3
  Head Types: Round head (R), countersunk (F), and oval head (O).
  Thread Type: Machine thread (UNF/UNC or metric).

Machine screws are used with pre-tapped holes or nuts and are ideal for machinery, electronics, and metal structures.

About ASM Fastener China

With over 14 years of manufacturing experience, ASM Fastener China specializes in producing fully threaded studs, stud bolts, and various types of industrial fasteners. Our main product range includes:

• ASTM/ASME Grades: A193 B7, B7M, B8, B8M, B16; A320 L7, L7M, L43

• Applications: Shipbuilding, FPSO, petrochemical, and offshore engineering projects

• Customization: Available according to customer drawings and international standards

ASM Fastener China combines strict quality control, material traceability, and timely delivery to ensure every product meets the highest industry standards.

Conclusion

From self-tapping screws to machine screws, each fastener type serves a unique purpose in engineering and construction. Understanding these differences helps ensure safety, efficiency, and durability in every project.

ASM Fastener China — your trusted partner for high-quality fasteners, delivering precision and reliability to industries worldwide.