English 
Español 
عربى 
Better Fastener Industry Co., Ltd. is a Square Head Bolts manufacturer in China supplying four-sided-head bolts for structural, foundation, timber, mining and heavy equipment assembly. Our range covers square head bolts produced to DIN 478, DIN 480, DIN 21346 and ASME/ANSI B18.2.1 (T1), in carbon steel and alloy steel, with hot-dip galvanizing and blackening finishes for outdoor and embedded service.
We operate as a direct manufacturer with in-house bolt, nut and washer production, an engineering team that develops parts from drawings or samples, and an in-house laboratory covering chemical composition, mechanical properties, non-destructive testing and dimensional inspection. Square head bolts sit alongside our wider Bolts range, so a single project can be supplied with matching nuts and washers from the same production chain.
Why Square Head Bolts Are Specified
The square head is a functional choice, not a legacy one. Its four flat faces give a wrench full-face engagement, so higher tightening torque can be applied before the head or tooling slips. In embedded installations the head corners bear against concrete, timber or cast material and lock the bolt against rotation while the nut is run down, removing the need for a holding fixture on the far side.
- High torque transmission: flat jaw contact across the full head width reduces cam-out and rounding compared with a worn hex.
- Anti-rotation in embedment: the square profile keys into concrete, timber or castings during nut tightening.
- Visual orientation: the square head shows the installed position of the bolt, useful on timber frames and fabricated structures.
- Field serviceability: a simple open-end or adjustable wrench is sufficient for assembly and re-tightening.
Our Square Head Bolt Range
We produce square head bolts in the standard families most often called out on structural, foundation and equipment drawings, and we develop non-standard heads, lengths and thread combinations from customer drawings or physical samples.
| Product Type | Reference Standard | Typical Application Fit |
|---|---|---|
| Square head bolt, metric series | DIN 478, DIN 480 | General structural steelwork, machine frames, brackets |
| Square head bolt, heavy pattern | DIN 21346 | Heavy engineering, mining and construction equipment |
| Square head bolt, inch series | ASME/ANSI B18.2.1 (T1) | North American structural, timber and repair work |
| Square head bolt, custom geometry | Customer drawing or sample | OEM assemblies, replacement parts, special head and shank forms |
Where a project needs a different head form, our related ranges include Hexagon Head Bolts, Foundation Bolts and T-head Bolts, and matching Square Nuts are produced in the same facilities.
Materials, Strength Grades and Finishes
Square head bolts are supplied in carbon steel and alloy steel, with grade selection driven by the working load, the corrosion environment and the mating material. Higher strength grades are used for heavy engineering applications where the bolt carries the primary structural load.
- Carbon steel: general structural and machinery assembly, with property class selected to the design load.
- Alloy steel: higher-strength heavy engineering and equipment applications.
- Stainless steel: available across our fastener production for corrosion-exposed assemblies.
- Hot-dip galvanizing: for outdoor, buried and underground structural environments.
- Blackening: for indoor machinery and equipment where a dark, low-reflectance finish is preferred.
Thread form, pitch, head width and head height are confirmed against the nominated standard before production, and we can quote both metric and inch series where the drawing calls for either.
Dimensions and Critical Specifications
The specification points that determine whether a square head bolt fits the application are the same ones we confirm at quotation stage. Small differences in head width or thread length change both the tooling and the installed behaviour.
- Nominal diameter and thread pitch, metric or inch
- Thread length: fully threaded or partially threaded shank
- Head width across flats and head height
- Overall length and shank diameter tolerance
- Property class or grade, and the corresponding mechanical property requirements
- Surface finish and coating thickness where corrosion protection is specified
- Thread tolerance class and gauging requirement
Application Fit Across Industries
Square head bolts are used where a bolt must resist rotation, accept high tightening torque, or be assembled with simple hand tools in the field. Our products serve rail transportation, automotive manufacturing, construction machinery, mining equipment, agricultural machinery, shipbuilding, petrochemicals, building and furniture hardware, and power accessories.
Structural and Foundation
Embedded bolts that key into concrete or cast material and resist rotation during nut tightening.
Mining and Construction Equipment
Heavy-duty joints that see high torque, shock loading and abrasive outdoor conditions.
Timber and Building Hardware
Square heads that hold position in timber and can be re-tightened on site with standard wrenches.
Custom Production and Configuration
Customized production is our core business. We develop and manufacture square head bolts from the drawings or samples a customer provides, covering special head dimensions, non-standard lengths, mixed thread forms and specific coating requirements. Our engineering team reviews the drawing against our production capability before quoting, so the configuration we offer is one we can actually run.
Where a project combines several fastener types, we consolidate them into one specification-led supply program rather than treating each part as a separate purchase. That approach is described in our Products range, which covers bolts, nuts, washers, screws and other fasteners from the same manufacturing base.
Quality Control and Acceptance
We apply total quality management across the production process. Inspection takes place after each process step, and 100% of finished products undergo final inspection against customer requirements and the applicable international standard.
- Spectrometer analysis of chemical composition
- Mechanical property testing for the specified grade
- X-ray flaw detection for internal defect screening
- Coordinate measuring machine inspection of head and shank geometry
- Thread gauging and dimensional checks against the nominated standard
Our production base operates 12 energy-efficient production lines, including one fully automatic shell molding line and four heat treatment lines, with annual capacity exceeding 20,000 tons. That capacity supports both large-volume orders and small to medium batch purchases.
Packing, Documentation and Delivery
Square head bolts are packed to suit the receiving channel: bulk export cartons, retail-ready kits, blister packs or custom boxes. We confirm the packing format with the order so the goods arrive in a condition that matches how they will be handled and sold.
Our location is within a two-hour drive of Shanghai and Ningbo ports, which supports sea freight as the main shipping mode, with air freight available through Ningbo or Shanghai airports for urgent deliveries. DDP delivery can be arranged to move goods directly to the customer's door.
Information We Use to Configure Your Solution
To prepare a square head bolt configuration and quotation, we work from the following project inputs. The more complete the drawing and application detail, the more precisely we can match the part to the installation.
| Input | What We Confirm From It |
|---|---|
| Drawing or physical sample | Head form, shank geometry, thread form and overall dimensions |
| Standard and grade | Material selection, mechanical property targets and inspection plan |
| Application and environment | Coating choice, corrosion protection level and service temperature |
| Quantities and delivery schedule | Batch planning, packing format and shipping mode |
| Mating parts | Whether matching nuts and washers should be supplied from the same production run |
Frequently Asked Questions
Which standards do you produce square head bolts to?
We produce square head bolts to DIN 478, DIN 480 and DIN 21346, and to ASME/ANSI B18.2.1 (T1) for inch-series requirements. Where a drawing references an equivalent standard or a customer-specific specification, we review it and confirm the applicable dimensions and grade before production.
What materials and finishes are available?
Square head bolts are produced in carbon steel and alloy steel, with higher strength grades for heavy engineering. Hot-dip galvanizing and blackening are available as surface treatments, giving corrosion protection for outdoor and underground structural environments or a dark finish for indoor machinery.
Can you manufacture square head bolts to our own drawing?
Yes. Customized production is our core business, and we develop and manufacture products from the drawings or samples you provide. Our engineering team reviews special head dimensions, non-standard lengths and coating requirements against our production capability before we quote.
How is quality verified before shipment?
Inspection is carried out after each process step, and 100% of finished products undergo final inspection against customer requirements and the applicable standard. Our laboratory is equipped with a spectrometer, coordinate measuring machine, X-ray flaw detector and other testing equipment to monitor chemical composition, mechanical properties, non-destructive testing and geometric dimensions.
Can square head bolts be supplied together with matching nuts and washers?
Yes. We manufacture bolts, nuts and washers within the same production base, so a project can be supplied with matched square head bolts, square nuts and washers as a single consolidated order rather than separate purchases.
What is your production capacity and delivery arrangement?
Our production base runs 12 energy-efficient production lines, including one fully automatic shell molding line and four heat treatment lines, with annual capacity exceeding 20,000 tons. We are within a two-hour drive of Shanghai and Ningbo ports, with sea freight as the main shipping mode and air freight available for urgent deliveries.
