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Selection Guide for Non-Standard Fasteners | Essential Handbook for Engineers

2026-08-14

Selection Guide for Non-Standard Fasteners | Essential Handbook for Engineers

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1. Non-Standard Fasteners Introdcution

Fasteners are indispensable basic components in modern manufacturing and engineering fields. Besides commonly seen standard fasteners, non-standard fasteners are gaining wider application. Thanks to their customizable features, non-standard fasteners can meet the demands of various special working conditions and environments.

Non-standard fasteners refer to parts that do not comply with international or national standards such as ISO, DIN, GB, ANSI, etc. They are usually designed according to customers’ special requirements with customized dimensions, shapes, materials or performance indicators. Widely adopted in special machinery, aerospace, shipbuilding, rail transit and other industries, they satisfy requirements for strength, corrosion resistance, high temperature resistance and other properties under diverse working conditions.

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Standard fastener example: 12.9 Grade Stripper Bolt

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Non-standard fastener example: Flange Bolt

2. Material Selection for Non-Standar Fasteners

Material selection is a critical factor affecting the performance of non-standard fasteners. Different materials vary greatly in tensile strength, corrosion resistance, wear resistance and other properties. Based on practical application requirements, the following materials are commonly used for manufacturing non-standard fasteners.

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Non-standard fastener example: Screws

Carbon Steel

Features

Carbon steel fasteners deliver favorable mechanical properties and high tensile strength. Classified into low-carbon, medium-carbon and high-carbon steel by carbon content, they are commonly available in strength grades of 4.8 and 8.8. Suitable for general mechanical structures, carbon steel fasteners tend to rust in humid or corrosive environments, so surface treatments such as zinc plating and Dacromet coating are required.

Application Scenarios

General machinery and industrial equipment;

Working conditions requiring high strength without strict corrosion resistance standards.

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Non-standard fastener example: Eye Bolt

Stainless Steel

Features

Stainless steel fasteners feature outstanding corrosion and oxidation resistance, maintaining stable performance in humid, acid-base and other harsh environments. Common grades include 304, 316 and 316L. With molybdenum added, 316 and 316L stainless steel offer superior corrosion resistance.

Application Scenarios

Ships, chemical equipment, food processing machinery;

High-humidity, high-salt or chemically corrosive environments.

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Non-standard fastener example: Customized Bolt

Alloy Steel

Features

By adding alloy elements including manganese, silicon, chromium and molybdenum, alloy steel fasteners achieve drastically improved strength, hardness, wear resistance and corrosion resistance, ideal for high-load and high-temperature special working conditions.

Application Scenarios

Aerospace, automobile manufacturing, wind power equipment;

High-temperature, high-pressure working conditions with impact loads.

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Non-standard fastener example: Copper Bushing

Copper & Copper Alloys

Features

Copper fasteners boast excellent electrical conductivity, thermal conductivity and corrosion resistance, as well as good ductility. They barely react with water and most chemicals, making them widely used in electrical and electronic equipment.

Application Scenarios

Power equipment, electronic components;

Scenarios requiring electrical conductivity and corrosion resistance.

Titanium & Titanium Alloys

Features

Titanium fasteners feature an exceptional strength-to-weight ratio, outstanding corrosion resistance and high temperature resistance. Their lightweight and high-strength advantages make them widely used in aerospace and high-end manufacturing industries.

Application Scenarios

Aerospace, medical devices, chemical equipment;

Extreme environments or applications with strict weight reduction requirements.

3. Specification Selection for Non-Standard Fasteners

Defining dimensions and specifications is vital when selecting non-standard fasteners. Specifications not only affect installation methods, but also determine load-bearing capacity and service life. Key specifications cover thread diameter, shank length and bolt head shape.

Thread Diameter

Thread diameter is one of the most important parameters of fasteners, directly determining load-bearing capacity. Generally, a larger diameter delivers higher load capacity, while installation space and connection demands of equipment should also be taken into consideration during selection.

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Shank Length

Shank length determines the installation depth of fasteners. Customized shank lengths are required for special occasions to guarantee stable fastening, especially for heavy mechanical structures. Improper length will lead to loose connections and compromise

equipment operation.

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Head Shape

Non-standard fasteners come in various head shapes, including hex head, cylindrical head and countersunk head. Head shape affects both appearance and installation efficiency.

Hex Head: The most common style, installed with wrenches, suitable for most mechanical equipment.

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Cylindrical Head: Neat appearance, ideal for applications requiring smooth surfaces.

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Countersunk Head: Fully embedded into workpieces for flush flat surfaces after installation.

4. Application Scenarios of Non-Standard Fasteners

Non-standard fasteners are widely used across nearly all industries. Enterprises can customize dedicated fasteners to match their working conditions and improve equipment reliability and durability.

New Energy Industry

Focusing on the safe operation of photovoltaic/wind power equipment, we provide customized photovoltaic bracket bolts, wind turbine flange bolts, and CNC structural components, coupled with third-party tensile strength and coating thickness testing, to ensure stable connections of new energy equipment in extreme environments.

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Machinery Manufacturing

Custom non-standard fasteners are widely adopted in large machinery manufacturing. Such parts need high strength, wear resistance and reliability to withstand complex environments and heavy-duty operation.

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Construction Engineering

The construction industry relies heavily on non-standard fasteners to meet unique structural demands, especially for large projects such as bridges and steel structures. The strength and durability of fasteners directly impact structural safety.

Automobile Manufacturing

The automotive industry imposes dual requirements on fasteners: sufficient strength and lightweight design. Custom non-standard fasteners made of aluminum alloy, titanium alloy and other materials reduce weight while guaranteeing strength and service life.

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Aerospace

Aerospace non-standard fasteners must deliver extreme strength, corrosion resistance and high temperature resistance. Titanium alloy and high-performance alloy steel are the preferred raw materials.

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Electronic & Electrical Appliances

Fasteners for electronic and electrical equipment need to be lightweight, durable, conductive and corrosion-resistant. Non-standard fasteners made of copper alloys dominate this field.

Haiyan Lewei Hardware specializes in custom non-standard fastener manufacturing. With in-depth expertise in the diversity and professionalism of non-standard fasteners, we deliver optimal tailored solutions for your projects!

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Petrochemical Industry

For high-temperature, high-pressure, and highly corrosive working conditions, we provide corrosion-resistant stainless steel bolts, high-strength double-ended studs, and CNC precision-machined pipe fittings, ensuring both sealing performance and corrosion resistance meet stringent international standards.
Corrosion Resistance: 316L stainless steel, 480h salt spray test, strong acid and alkali resistance

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Haiyan Lewei Hardware Tools Co., Ltd. is an integrated manufacturer of customized fasteners with world-class production equipment. Unlike standard fasteners complying with ISO, DIN, GB and ANSI standards, non-standard fasteners are tailor-made for special sizes, materials and performance to fit aerospace, auto, machinery, marine and electronics industries.