HEX BOLTS

The products are strictly conform with DIN, ISO, ASTM, ANSI, BS, JIS...

● Level: A325/A325M/A490/A490M/8.8 /10.9/12.9/Gr5/Gr8

● Coating: Plain/Black/Galvanized/H.D.G /YZP/Dacromet/Xylan

ASTM B7/B7M

THREAD RODS

The longest can reach 3.66 meters(12FT)

China Professional Metal Fasteners

Manufacturer and Supplier with Over 20 Years of Experience

Bolt

Head shape: Hexagonal head, square head, round head can all be produced.
Size: M4-M100, 3/8 "-4"...

Nut

Type: hex nut, cap nut, couple nut, lock nut, spring nut
Size: M4-M100, 3/8'-4' is divided...

Washer

Type: Flat washer, spring washer
Specifications: M3-M100, 1/4

Threaded Rod

Size: M4-M100, 3/8 "-4", divided into metric size and inch size
Thread type: Full Thread

Precast Accessories

Size: Customization based on drawings or samples, both metric size and inch size are available

Custom Fasteners

Size: Customization based on drawings or samples, both metric size and inch size are available

About Material

Carbon steel, alloy steel, stainless steel are all acceptable.
According to customer requirements

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Topbolt - Best Standard Bolts and Nuts for Your Industries

The products are applied to architectural steel structures, brigdes, oil, pipeline, machinery equipment, furniture, vessel, railway.

Bridge
Industry
Ship
Solar Power
Steel Structural

Why Choose Topbolt for Your Projects?

Trusted Supplier of Bolts, Nuts, and Fasteners Conforming to DIN, ANSI/IFI, JIS, BS, ISO, and GB Specifications.

Ningbo Topbolt Metalworks Co., Ltd. is a manufacturer in China which mainly produces high strength fasteners and specializes in all kinds of hardwares. Founded in 2001, In the past few years, it developed fast with its factory located in Ningbo Zhenhai Chemical industrial area and its headquarter /foreign sales department in Ningbo Jiangdong Eastern Business Centre.

The factory now covers an area of approximately 15,000 square meters, with monthly production capacity of 2000 tons. The company has its all-around research system, supply management, large-scale warehouse...

Founded In

㎡

Covers an Area

Monthly Production Capacity

million

Annual Sales

DIGITAL SHOWROOM

If you want to learn more about our manufacturing capabilities, you can click on the avatar in the scene, or accept my invitation!

What Makes Topbolt Fasteners Manufacturing Stand Out?

Material Science

Carbon steel, alloy steel, stainless steel, Special material customization
Direct procurement from raw material factories, discounted prices, and sufficient stock availability

Standard

Strictly produce according to standard dimensions such as DIN, ISO, GB, JIS, ASTM, SAE, ASME, etc

Services

Accept customized production (including sample processing, drawing processing), OEM production

Topbolt News & Fasteners Knowledge Center

Circlip DIN471 / DIN472 Selection: Mix Shaft & Bore Rings Leads to Ejection

2026-10-29

Elastic circlips are common axial retaining fasteners for machinery assembly and overseas equipment repair. Many overseas buyers and maintenance engineers mistakenly mix up DIN471 shaft circlips and DIN472 bore circlips. These two types differ fundamentally in structure, spring direction and matched groove dimensions, and they cannot be interchanged. Once mismatched, the circlip cannot lock components reliably and will pop out under vibration, leading to component shifting, equipment downtime and bulk rejection. This article clarifies the application boundary of both standards, sorts out selection check points and groove matching requirements to avoid disputes in maintenance procurement.

2026-10-29

ISO 4017 Fully Threaded Hex Head Bolt.png

Hot Dip Galvanized HDG Bolt Thread Interference & Matching Guide

2026-10-28

Many buyers match hot dip galvanized HDG bolts with standard plain nuts directly, without considering the coating thickness occupying the thread space. The galvanized layer adds material on the thread flank and causes thread interference, bolts cannot be fully tightened. This article covers HDG thread allowance rules, nut tapping oversize requirements, ASTM A153 standard notes and common procurement traps, helping you avoid on-site assembly failure and rework cost.

2026-10-28

6H/6g VS 5g6g Thread Fit: Fastener Procurement Guide

2026-10-27

Many overseas buyers and suppliers mix up 6H/6g and 6H/5g6g thread tolerance combinations without clear understanding of tolerance band differences. This mistake leads to frequent inspection failures during incoming quality control, especially after electroplating. Tight tolerance of 5g6g leaves limited margin for coating thickness, which easily causes thread oversize and gauge rejection. This article clarifies the definition, applicable scenarios, inspection logic and procurement specification rules for these two tolerance matches, helping buyers avoid costly batch rejections.

2026-10-27

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We welcome all of you from all over the world to join us for the win-win business partnership and friendship, welcome to China, welcome to Ningbo Topbolt!

China Professional Metal Fasteners

Topbolt - Best Standard Bolts and Nuts for Your Industries

Why Choose Topbolt for Your Projects?

DIGITAL SHOWROOM

Circlip DIN471 / DIN472 Selection: Mix Shaft & Bore Rings Leads to Ejection

Hot Dip Galvanized HDG Bolt Thread Interference & Matching Guide

6H/6g VS 5g6g Thread Fit: Fastener Procurement Guide

Get A Free Quate

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