Screw Core Classifications:
Machine Screws: These have standard mechanical threads (e.g., metric, imperial) and must be screwed into pre-machined internal threaded holes. The shank can be fully or partially threaded, used for precision assembly.
Self-Tapping Screws: These have the ability to drill, tap, and push, eliminating the need for pre-drilled internal threaded holes. Subcategories:
Ordinary Self-Tapping Screws: Used for plastics, wood, and thin metal sheets.
Self-Drilling Self-Tapping Screws: These have a drill tip that can penetrate steel plates, eliminating the need for pre-drilling and greatly improving efficiency.
Wood Screws: These have deep threads, large pitch, and sharp teeth, specifically designed for wood, providing strong locking force.
Set Screws: Used to fix the relative position of parts, preventing slippage or rotation. Various end shapes are available:
Tapered End: Provides high locking force, suitable for surfaces with high hardness.
Flat End: Large contact area, does not damage the surface.
Concave End/Cylindrical End: Used for positioning or pressing into holes on shafts.
Structural screws: a type of high-strength self-tapping screw that has undergone heat treatment and can be used to replace traditional bolts for steel structure connections, making installation faster.
