❓ What are the types of screws? What are their respective uses?

🔩 Screw Types

Summary：
Screws are classified by head shape, drive type, and thread form. They serve specific functions in wood, metal, plastic, and composite materials.

Explanation：
Common types include flat head, pan head, hex head, and countersunk screws. Drive styles vary, such as Phillips, slotted, Torx, and hex socket. Thread types include machine screws for metal, self-tapping for plastic, and wood screws for timber. Each type matches distinct usage and installation requirements.

🧰 Screw Applications

Summary：
Screws are used for structural fastening, assembly, or anchoring across various industries.

Explanation：
In furniture hardware, screws are essential for hinges, drawer systems, and connectors. In construction and manufacturing, screws provide secure load-bearing attachment for frames, panels, and mechanical joints. Selecting the correct screw ensures strength, durability, and safety.

📏 Metric, Imperial, and U.S. Standard Screws

Summary：
Screws are available in metric (mm), imperial (inch), and UNC/UNF (U.S.) systems. Understanding the differences is key to correct sizing and compatibility.

Explanation：

• Metric screws: Labeled by diameter × pitch (e.g., M6 × 1.0).

• Imperial screws: Defined by inch fractions (e.g., 1/4", 3/8") or gauge numbers (e.g., #6, #8).

• U.S. Standard (UNC/UNF): Unified thread standard (coarse or fine) commonly used in mechanical and automotive parts.
  Always refer to a conversion chart when replacing or matching screw sizes between systems.

🛡️ Anti-Loosening & Surface Treatments

Summary：
Some screws are enhanced with anti-loosening features or surface coatings to extend durability and resistance.

Explanation：
Anti-loosening treatments include thread-locking adhesives, serrated washers, or nylon patches. Surface treatments such as zinc plating, black oxide, nickel, or chromate coating improve corrosion resistance and appearance. Some fasteners also undergo heat treatment to improve hardness and load capacity. These enhancements are common in automotive, furniture, and industrial uses.