2024-11-17
Principles and methods of thread inspection
Thread inspection is one of the most controversial events in trade. Due to the inconsistency of thread inspection methods and rules, thread gauges sometimes "fight" with each other.
Different coatings on the surface of threaded fasteners, thread gauge disputes caused by surface coatings (after electroplating, Dacromet, and hot-dip galvanizing) will directly affect the interchangeability of threads! Sometimes there are disputes over thread inspection after coating, how to inspect the thread ends and surface bumps, and thread deformation after heat treatment?
Thread inspection disputes and inspection rules characteristics
Thread inspection is one of the most controversial events in trade. Due to the inconsistency of thread inspection methods and rules, thread gauges sometimes "fight" with each other.
Different coatings on the surface of threaded fasteners, thread gauge disputes caused by surface coatings (after electroplating, Dacromet, and hot-dip galvanizing) will directly affect the interchangeability of threads! Sometimes there are disputes over thread inspection after coating, how to inspect the thread ends and surface bumps, and thread deformation after heat treatment?
Purpose of thread inspection
If the internal and external threads of the fasteners used are not interchangeable, the parts cannot be assembled; if the assembled threads cannot withstand a certain load, or are damaged early after assembly, the thread tightening function will be lost.
The factors affecting the interchangeability and precision of threads mainly include:
——Major thread diameter
——Medium diameter (single medium diameter)
——Minor diameter
——Flank angle
——Lead angle
The interaction of various thread parameters such as pitch is directly reflected in the effective medium diameter of the thread, that is, the matching size.
