The appearance quality inspection is the first step before each nut leaves the factory. Through visual inspection or using a magnifying glass, it is checked whether there are any defects such as cracks, folds, or burrs on the surface of the nut.
1.The dimensional accuracy test ensures the compatibility of the nut with the wrench and the bolt. The key test dimensions include:
| Test items | Tolerance requirements | Reference standards |
| Edge width (S) | ±0.15mm ~ ±0.60mm | GB/T 6170 / ISO 4032 |
| Diagonal dimension (e) | Within the standard tolerance range | ISO 4032 |
| Thickness (m) | ±0.3mm | ISO 4032 |
| Inner hole roundness | ≤0.05mm | GB/T 6170 |
| Edge parallelism | Complies with the standard requirements | ISO 4032 |
| End face perpendicularity | Complies with the standard requirements | ISO 4032 |
2.The inspection of thread accuracy is the key factor determining whether the nut and the bolt can fit together smoothly. The main inspection items include:
| Test items | Testing methods | Acceptance criteria |
| Thread gauge (GO) | Thread gauge test | Should be able to rotate smoothly |
| Thread plug gauge (NO GO) | Thread plug gauge test | Should not be able to be inserted more than 2 turns |
| Pitch tolerance | Thread comprehensive measuring instrument | 6H |
| Cumulative pitch error | Thread comprehensive measuring instrument | ≤0.025mm/25mm |
| Pitch angle | Thread comprehensive measuring instrument | Complies with standard requirements |
The three tests of appearance, size and thread accuracy ensure that the Strong clamping force Precise thread Hexagonal Nut has "visible quality" - the surface is free of defects, the size matches the wrench, and the thread is compatible with the bolt.
The after-sales service provided by the high-quality fastener supplier Xiaoguo should go beyond "replacement for broken items". It should also include technical support, usage guidance and maintenance assistance. We are committed to helping customers prevent problems in the first place, rather than merely responding passively after the problems occur.
1.Professional technical support
If you encounter any problems during the selection, installation or usage process, our technical team can provide:
Selection guidance: Based on your operating conditions, we recommend the most suitable material, performance grade, and surface treatment option.
Installation torque recommendations: Provide recommended tightening torque values for different specifications of Strong clamping force Precise thread Hexagonal Nut to ensure connection reliability
Fault analysis: In case of problems such as stripped threads, fractures or rusting, we can assist in analyzing the causes and proposing improvement solutions.
Drawing and customization assistance: For non-standard or special requirements, we can provide suggestions for manufacturability design.
2.Maintenance services and on-site support
For equipment where the nuts have failed due to special circumstances, our service system can provide targeted repair support:
Free repair within warranty period: In case of damage caused by our products' issues, free repair services will be provided within the warranty period.
Customized product repair: Non-standard products or secondary processed components also enjoy repair guarantees during the warranty period.
Remote fault diagnosis: Quickly determine the cause of the problem through images, videos, etc., and provide handling suggestions.
Flexible service method: Customers can submit applications online