Product Specifications
| Model / Specification | M3 – M12 |
| Material | Carbon Steel |
| Thread Size d |
M3 | M4 | M5 | M6 | M8 | M10 | M12 | |
| a | Max | 1.0 | 1.4 | 1.6 | 2.0 | 2.5 | 3.0 | 3.5 |
| da | Max | 2.8 | 3.8 | 4.7 | 5.6 | 7.5 | 9.4 | 11.2 |
| r | Min | ③ | ③ | ③ | ③ | 0.1 | 0.1 | 0.1 |
| h ② | Nominal | 0.5 | 0.8 | 1 | 1.6 | 1.6 | 2.0 | 2.5 |
| H | Nominal | 2 | 2.75 | 3.25 | 4 | 5 | 6.25 | 7.5 |
| dc | Nominal | 7 | 9 | 10 | 12 | 16 | 20 | 24 |
| d2 | Reference | 5.23 | 6.78 | 8.75 | 10.71 | 13.64 | 16.59 | 19.53 |
| Wt/1000 pcs (Steel) ≈ kg | - | - | - | - | - | - | - | |
Hex Combination Bolt — Product Introduction
The hex combination bolt is a standardized fastener that combines a hex head bolt, a spring washer, and a flat washer into a pre-assembled unit, executing the GB/T 9074 series of national standards. It is absolutely not a non-standard customized part. Its “one set replaces three pieces” design enables faster and more accurate assembly. The product is available in both carbon steel and stainless steel materials, with carbon steel in mainstream grades such as 45 steel and 35CrMo, and stainless steel in A2-70 (304), covering everything from ordinary industrial assembly to heavy steel structure applications.
I. Product Features
Three-in-One Integration, Permanently Secured
After the bolt threads are rolled, the washer is locked permanently onto the shank. It will not fall off during transport or installation, fundamentally eliminating the risk of missed washer installation.
Process Determines Specifications, Cold and Hot Each Have Their Strengths
Small规格 bolts adopt cold-heading forming, offering high precision; large规格 bolts above M27 adopt red-forging forming, ensuring strength. The entire series covers standard models.
Material Can Be Selected Freely
You can choose carbon steel (pursuing strength and cost advantages) or stainless steel (pursuing corrosion resistance and appearance), entirely based on the usage environment.
II. Product Advantages
Efficiency Doubled, Labor Halved
Workers no longer need to thread washers one by one — just pick it up and use it. One bolt saves 3 seconds; the working hours saved across 10,000 units of equipment far exceed the purchase price difference.
Professionally Matched, Extended Service Life
The hardness of the spring washer and flat washer is strictly matched to the bolt grade, preventing loosening failure caused by washers that “cannot withstand” the load.
Simplified Inventory, Easy Management
One material code represents one complete fastener assembly, eliminating the cumbersome management of four separate item numbers for bolts, nuts, spring washers, and flat washers.
III. Scope of Application
General Machinery and Sheet Metal Assembly: Choose GB/T 9074.17 carbon steel grade 8.8, offering the widest versatility.
Outdoor or Humid Environments: Choose the same model in stainless steel A2-70, providing corrosion resistance without rusting.
Steel Structures and Heavy Equipment: Choose GB/T 9074.23 large hex head combination, using 35CrMo material, offering high load capacity and reliable anti-loosening performance.
Automated Production Lines: Combination bolts are the ideal partner for automatic tightening machines, with uninterrupted feeding and continuous tightening without jamming.
