Step Bolts are heavy-duty fastening components designed with a smooth, flat or low-profile head and a precision-threaded shank, widely used in structural assemblies, electrical infrastructure, and heavy industrial frameworks. These fasteners are engineered to provide secure clamping where load distribution, vibration resistance, and long-term mechanical stability are critical. Manufactured in compliance with standards such as DIN, ISO, ASTM, and BS, Step Bolts are commonly produced in stainless steel (SS 304, SS 316), carbon steel, and alloy steel grades depending on environmental and load conditions.



In industries such as construction, power generation, railway infrastructure, and mechanical fabrication, Step Bolts ensure stable anchoring in demanding conditions. Their design minimizes surface projection while maintaining high tensile strength, making them ideal for confined or safety-critical installations.
KK Fasteners supplies industrial-grade Step Bolts engineered for global projects, offering full material traceability and export-ready quality control systems trusted by engineering contractors worldwide.
| Parameter | Specification Options |
|---|---|
| Material Grades | Stainless Steel (SS 304, SS 316), Carbon Steel (A36, A307), Alloy Steel |
| Thread Type | Metric (M6–M36), UNC, UNF |
| Standards | DIN 603, ISO 8677, ASTM A307, BS 1768 |
| Head Type | Round head, flat bearing head |
| Length Range | 20 mm to 300 mm (custom sizes available) |
| Surface Finish | Plain, Zinc Plated, Hot Dip Galvanized, Black Oxide |
| Tensile Strength | Up to 800 MPa (depending on grade) |
| Hardness | 18–35 HRC (material dependent) |
| Manufacturing Process | Cold forging, precision CNC machining, thread rolling |
| Step Bolts | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Nominal or Basic Product Diameter |
Diameter of Full Size Body (E) | Diameter of Head (A) | Head Height (H) | Square Width (O) | Square Depth (P) | ||||||
| Max | Min | Max | Min Sharp | Max | Min | Max | Min | Max | Min (Basic) | ||
| 10 | 10.000 | .199 | .182 | .656 | .625 | .114 | .094 | .199 | .185 | .125 | .094 |
| 1/4 | .2500 | .260 | .237 | .844 | .813 | .145 | .125 | .260 | .245 | .156 | .125 |
| 5/16 | .3125 | .324 | .298 | 1.031 | 1.000 | .176 | .156 | .324 | .307 | .187 | .156 |
| 3/8 | .3750 | .388 | .360 | 1.219 | 1.188 | .208 | .188 | .388 | .368 | .219 | .188 |
| Nominal Bolt Diameter | Up to 1 in., incl. | Over 1 in. to 2-1/2 in., inl. | Over 2-1/2 in. to 4 in., inl. |
| No. 10 through 3/8 | +0.02, -0.03 | +0.02, -0.04 | +0.04, -0.06 |
Step Bolts are used wherever controlled clamping, structural alignment, and vibration resistance are required in industrial systems.
Step Bolts are manufactured using cold forging and precision thread rolling techniques to achieve superior grain flow and mechanical strength. The process ensures minimal material waste while enhancing load-bearing capacity. CNC machining is used for dimensional accuracy in custom specifications.
Each batch undergoes strict quality inspections including dimensional verification, hardness testing, tensile strength validation, and surface coating checks. Traceability systems ensure every lot can be tracked back to raw material sourcing.
KK Fasteners follows ISO 9001-certified quality systems, ensuring every Step Bolt meets international performance and safety standards required for critical engineering applications.

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Step Bolts are industrial fasteners designed with a low-profile or flat head and a threaded shank, used for secure structural fastening. They are commonly applied in steel structures, machinery assemblies, and infrastructure systems where stable clamping and vibration resistance are required.
The best material depends on the application. Stainless steel (SS 304, SS 316) is preferred for corrosion resistance in marine and outdoor environments. Carbon steel is used in general construction, while alloy steel is chosen for high-strength and heavy-load industrial applications.
Yes, Step Bolts are typically manufactured in compliance with DIN 603, ISO 8677, ASTM A307, and BS standards. These ensure proper dimensional accuracy, mechanical strength, and compatibility with international engineering systems.
Step Bolts are widely used in structural steel construction, railway systems, power transmission towers, industrial machinery, and electrical panel installations. They are selected where reliable fastening under load and vibration is required.
A reliable manufacturer should provide ISO-certified production, material traceability, compliance with international standards, and consistent quality testing. Export capability, technical documentation, and customization support are also key indicators of a dependable supplier. Companies like KK Fasteners support global industrial procurement with these capabilities.
Step Bolts are critical fastening elements in structural and industrial engineering, where reliability and precision directly impact system performance. With controlled manufacturing processes and strict quality verification, KK Fasteners delivers Step Bolts engineered for demanding global applications.
For technical specifications, custom requirements, or bulk export inquiries, connect with the engineering team at KK Fasteners to receive application-specific support and a detailed quotation.