A394 Hex Tower Bolts

As an A394 Hex Tower Bolts manufacturer, JIAXING SINI FASTENER CO., LTD. produces carbon steel tower bolts for the steel-to-steel connections of power transmission towers, substations and comparable lattice structures. Established in 2004, we have more than 20 years in the fastener field and supply standard and custom-engineered bolts and screws from production facilities in Haiyan, Zhejiang and Lianyungang, Jiangsu.

A394 tower bolts leave our works hot-dip galvanized and are normally assembled with a Grade A hex nut and a lock washer, so the set arrives at the tower site ready for erection. Our bolt production covers diameters from 3/16 in. to 1 1/2 in. (5–52 mm) and lengths from 1/2 in. to 60 in. (10–1500 mm), which lets us extend the standard tower bolt listing when a project calls for a non-standard length or thread.

A394 Hex Tower Bolts: Product Range at a Glance

Where A394 Tower Bolts Fit

Tower bolts are specified for connections where two steel members are clamped directly together and the joint is exposed to weather for the life of the structure. The hex head gives a positive wrenching face on angle, plate and gusset assemblies, and the galvanized finish carries the joint through decades of outdoor service.

• Lattice transmission towers — leg splices, bracing and cross-arm connections
• Substation structures — gantries, support frames and equipment steelwork
• Steel-to-steel joints in similar exposed frameworks where A394 is the governing specification
• Replacement and maintenance stock for line and substation refurbishment programmes

Type 0, Type 1 and Type 3 — Matching the Grade to the Joint

The three A394 types differ in steel chemistry and heat treatment, which changes the minimum mechanical properties and the corrosion behaviour of the finished bolt. We confirm the type at order review and hold the corresponding steel and process route through production.

Dimensions, Threads and Head Configuration

Every tower bolt is produced to a defined diameter, length and thread series, and the head carries the identification required by the project. We work from the referenced standard or from a customer drawing, and we confirm the thread series and class at order review rather than assuming a default.

• Diameter range: 1/2 in. to 3/4 in. for the standard A394 listing
• Length range: 7/8 in. to 15 in., with longer shanks available from our wider bolt capacity
• Head: hex, sized to the bolt diameter and struck with the agreed identification
• Thread: inch-series thread to the drawing or referenced standard, with class confirmed before threading
• Point and end finish: chamfered or as drawn, so the bolt enters the hole without galling the coating

Hot-Dip Galvanizing and Thread Fit

Hot-dip galvanizing is the finish that keeps a tower bolt serviceable in an outdoor environment, and it is also the step that most often causes assembly problems when it is not planned. Zinc builds on the thread, so the nut must be matched to the coated bolt rather than to the bare one.

• Coating class and zinc weight are confirmed against the order or the referenced galvanizing standard before the dipping batch is released
• Nuts supplied with galvanized bolts are tapped to suit the coating so they run on by hand through the full thread length
• Threads are inspected after coating for run-on, pitch and coating build-up
• Coating adhesion and appearance are checked on finished parts, with salt spray testing available as supporting evidence

Nuts, Lock Washers and Matched Assemblies

A394 tower bolts are normally shipped as a set: bolt, Grade A hex nut and lock washer. We match the nut and washer to the bolt diameter, thread and coating so the assembly behaves as one unit on site, and we can supply the components separately when a project stocks them independently.

Our nuts and washers are produced in the same facilities as the bolts, which keeps the coating and thread fit consistent across the set. Where a project uses a heavier structural bolt instead, our Heavy Hex Bolts cover the larger wrenching and load cases.

Quality Control and Acceptance Testing

Inspection is carried out after each process, and finished products are inspected against the customer's requirements and the applicable international standard. SINI FASTENER is ISO 9001 certified, and our laboratory equipment supports the checks that tower bolt specifications normally call for.

• Optical Emission Spectrometer (OES) for chemical composition verification
• Universal Testing Machine and tensile testing machine for mechanical properties
• Hardness tester for heat-treatment verification on Type 1 and Type 3
• Video Measuring System for dimensional and thread inspection
• Metallographic microscope for microstructure checks
• Salt spray test chamber for coating performance

Information We Use to Configure Your Solution

We prepare a tower bolt configuration and quotation from the working point of the joint, not from a catalogue line alone. The following inputs let us fix the steel, the process route and the inspection plan before production starts.

Documentation, Packaging and Delivery Scope

Finished Carbon Steel Hot-dip Galvanized Hex Tower Bolts are packed to the agreed configuration — carton, pallet or bulk — and labelled to the customer's marking instruction so that sets stay together through the container. Test reports, dimensional records and coating checks are issued with the shipment where the order calls for them.

Because we also produce carriage bolts, timber bolts, plow bolts and a full range of screws, threaded rods and studs, a tower project can consolidate its steel fasteners with one supplier. Custom items are developed from customer drawings or samples, in inch or metric sizes, in carbon steel or stainless steel as the application requires.

Frequently Asked Questions

What is an ASTM A394 hex tower bolt used for?

It is a galvanized carbon steel bolt made for steel-to-steel connections in power transmission towers, substations and similar structures. The hex head gives a positive wrenching face on angle and plate assemblies, and the hot-dip galvanized finish is intended for joints that stay exposed to weather.

Which A394 type should be specified — Type 0, Type 1 or Type 3?

Type 0 is the general-purpose grade for standard tower and substation connections. Type 1 is quenched and tempered for higher-strength, more heavily loaded joints. Type 3 is quenched and tempered weathering steel, chosen where atmospheric corrosion resistance is part of the specification. We confirm the type at order review and hold the matching steel and process route through production.

What sizes of A394 tower bolts do you manufacture?

Our standard A394 listing covers diameters from 1/2 in. to 3/4 in. and lengths from 7/8 in. to 15 in. Our wider bolt capacity runs from 3/16 in. to 1 1/2 in. (5–52 mm) in diameter and 1/2 in. to 60 in. (10–1500 mm) in length, so non-standard shank lengths can be produced to drawing.

Are the bolts supplied with nuts and washers?

Yes. A394 tower bolts are normally assembled with a Grade A hex nut and a lock washer, and we match both components to the bolt diameter, thread and coating so the set runs together on site. Bolts can also be shipped without nuts and washers when a project stocks them separately.

How is the hot-dip galvanized coating controlled?

The coating class and zinc weight are confirmed against the order or the referenced galvanizing standard before the dipping batch is released. Nuts are tapped to suit the coated thread so they run on by hand, threads are inspected after coating for run-on and pitch, and salt spray testing is available as supporting evidence.

Can you produce tower bolts to our own drawing?

Yes. We develop and produce items from customer drawings or samples, in inch or metric sizes, and we can vary head marking, length, thread and coating to suit the connection. Send the drawing or sample with the quantity and coating requirement, and we will return the configuration and inspection plan.