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Product details

Tower Climbing Step Bolt | ASTM A394 HDG Step Bolts | Yokelink

Yokelink Step Bolts are mission-critical climbing fasteners designed specifically for steel lattice towers, monopoles, and communication structures. Forged from high-strength carbon steel, these heavy-duty bolts provide a secure, slip-resistant foothold for linemen and maintenance crews working at extreme heights.

Uncompromising Strength & Durability: Manufactured to meet or exceed ASTM A394 specifications, our step bolts feature a large, low-profile button head that ensures maximum bearing area for the climber's boots, reducing foot fatigue and preventing slippage. The heavy square neck prevents the bolt from turning during installation. To guarantee decades of reliable, rust-free service in harsh outdoor environments, every Yokelink step bolt and matching heavy hex nut is thoroughly Hot Dip Galvanized according to ASTM A153 Class C.

Key Features of Step Bolt

Head Style: Large Button Head for optimal boot support and safety.

Standard: Conforms strictly to ASTM A394 structural requirements.

Neck Design: Square neck prevents rotation while tightening.

Corrosion Protection: Fully Hot Dip Galvanized (HDG) to ASTM A153.

Assembly: Supplied complete with matching HDG Heavy Hex Nuts.

Production Process of Step Bolt

Step bolts are manufactured from ASTM A307 carbon steel. After straightening and cutting, the round head and step shoulder are formed by cold heading to ensure accurate dimensions. The shank goes through thread rolling for precise threads. Heat treatment is applied to meet mechanical property requirements. All bolts are hot-dip galvanized per ASTM A153 for corrosion resistance. The whole production and inspection comply with IEEE C135.1 and IEEE C135.80, widely used for overhead line and pole hardware fastening.

Yokelink Quality Control and Testing Equipments

We don't just reference standards; we also verify them in practice: each batch of products undergoes destructive tensile testing in our internal laboratory to ensure load performance exceeds the minimum requirements of IEEE C135.1 / IEEE C138.80 or CSA specification; we use optical comparators to ensure the geometric accuracy of chamfered tips and rolled threads, enabling convenient on-site installation; at the same time, we conduct comprehensive testing on Rockwell hardness, coating thickness, and other parameters, and each shipment is accompanied by the original manufacturer's material specifications (MTRs) and quality inspection reports, with all data traceable back to the raw material furnace number.

The Application of Step Bolt

Step bolts are widely used in overhead transmission and distribution lines, mainly for securing cross arms, insulators, and pole-mounted hardware. Their unique step shoulder design ensures stable positioning and prevents rotation during installation. Made from ASTM A307 carbon steel and hot-dip galvanized per ASTM A153, they feature high strength and excellent corrosion resistance. Fully compliant with IEEE C135.1 and IEEE C135.80 standards, they provide safe, reliable fastening for long-term outdoor power line operations.

Yokelink Product Quality Inspection Report

We provide comprehensive inspection services for machine bolts, including SGS test bolts and formal Production Part Inspect Report (PPIR). The SGS tests verify the bolts’ compliance with international standards like ASTM A307 and IEEE C135.80, covering mechanical properties and corrosion resistance. The PPIR details all inspection items, ensuring each machine bolt meets dimensional, performance and quality requirements, providing reliable quality assurance for overhead line and industrial applications.

Technical Specifications of Step Bolt

Part No.	Size	Bolt Length	Thread Length	Weight
Part No.	Size	Inch(A)	Inch(B)	Kg / Pcs
A0812-4.5	1/2"X4-1/2"	4-1/2	2	0.214
A0812-08	1/2"X8"	8	4	0.286
A0858-04	5/8"X4"	4	2	0.323
A0858-5.5	5/8"X5-1/2"	5-1/2	3	0.386

Frequently Asked Questions (FAQ)

Q1: What is the purpose of a step bolt on a transmission tower?

A: A step bolt is a specialized fastener installed on the legs of steel lattice towers and monopoles to serve as a permanent climbing step. It allows linemen and maintenance personnel to safely ascend and descend the structure. The bolt features a large button head to prevent the climber's boot from slipping off the edge.

Q2: Why are step bolts made with a square neck?

A: The square neck right below the head of the step bolt fits perfectly into the pre-punched square holes on the tower's steel angle brackets. This prevents the bolt from spinning while the heavy hex nut is being tightened on the opposite side with a high-torque wrench, allowing for faster and safer single-handed installation.

Q3: Can standard carriage bolts be used instead of ASTM A394 step bolts?

A: No. While they look similar, standard carriage bolts do not have the guaranteed shear strength, tensile properties, or the specific head diameter required for safe climbing. Yokelink step bolts are manufactured to ASTM A394 standards, ensuring they can safely support the dynamic weight of a fully equipped lineman.

Value-Added Supply Chain Services

1. Blanket Order & Free Warehousing

Yokelink offers Blanket Order programs: Place an annual order to lock prices, we manufacture your total volume and hold stock in our facility free of charge. Split Shipments: Schedule partial shipments (e.g., monthly or quarterly) based on your project progress. You get the benefits of just-in-time delivery without the risk of shortages.

2. DDP Shipping (USA Duties Included)Landed Cost Certainty

We handle the complex logistics. Our DDP (Delivered Duty Paid) service covers sea freight, US Customs clearance, and Section 301 tariffs. The price we quote is the final price delivered to your door / Warehouse.

3. Free Sample Program

We offer Free Samples to qualified commercial buyers for testing and approval.

Reference Information:

For IEEE C135.1 technical details behind our specification, see Understanding IEEE C135.1 Standard

https://www.yokelink.com/blog/understanding-ieee-c135-1-standard-for-zinc-coated-steel-bolts-and-nuts-in-overhead-line-construction-32333.html