Custom Fastener Engineering Solutions
Learn how to choose materials, control quality, and optimize fasteners for safe and efficient manufacturing.
Engineering Resources
Fastener Technical Specifications & Engineering Support
Fastening technology is our core expertise. Our engineers provide practical guidance on fastener design, materials, performance, and applications to help customers improve product reliability and manufacturing efficiency.
International Thread Types and Size Standards for High-Performance Fastener Solutions
Engineering Classification for Global Procurement & Manufacturing
Metric thread system is the global fastening standard for stainless steel screws, bolts, and nuts under ISO and DIN specifications. It uses a 60° V-thread profile and a standardized tolerance system (6g/6H) to ensure full interchangeability in global manufacturing.
It is widely applied in machinery, automotive, construction, and industrial equipment where international compatibility and stable mass production are required. Metric fine pitch variants are used in precision assemblies requiring higher vibration resistance and better clamping control.
From a procurement perspective, ISO metric threads offer the lowest engineering risk due to global standardization and broad supplier availability.
Unified thread system is the inch-based fastening standard defined by ASME B1.1 and used primarily in North American engineering systems. Although it shares a 60° profile with metric threads, it is not dimensionally compatible.
UNC threads are used for general-purpose fastening requiring strong engagement and easy assembly, while UNF threads are applied in precision systems requiring higher vibration resistance and controlled preload.
This system is widely used in industrial machinery, aerospace components, automotive systems, and maintenance applications designed under inch-based engineering standards.
From a procurement perspective, strict adherence to original specifications is required to avoid incompatibility between metric and inch systems.
Specialty thread systems are used when ISO metric or Unified standards cannot meet specific engineering requirements. These systems are defined by application performance, OEM drawings, or non-standard mechanical design needs.
Fine pitch and optimized thread geometries are used in precision engineering applications to improve vibration resistance, preload stability, and locking performance. These are commonly used in precision machinery, instrumentation, and high-performance assemblies.
High-strength stainless steel grades such as A4-70 and A4-80 are often combined with these thread systems to ensure both corrosion resistance and mechanical load capacity in critical environments.
OEM custom threads are manufactured based on engineering drawings and require strict validation to ensure correct fit, engagement, and long-term reliability.
From a procurement perspective, these systems offer maximum flexibility but require higher engineering control and supplier capability.
Types of Stainless Steel Materials for Fasteners | Grades, Properties & Applications
Overview of stainless steel fastener material types, including austenitic, ferritic, martensitic, duplex, and precipitation-hardening grades with their properties and applications.
- Composition: 16–26% Cr, 3.5–22% Ni, low carbon (0.03–25%)
- Key Properties: Excellent corrosion resistance, non-magnetic, high ductility, and excellent weldability
- Composition: 11–27% Cr, medium carbon (0.08–20%), low nickel content
- Key Properties: Good corrosion resistance, moderate strength, magnetic behavior, and cannot be hardened through heat treatment.
- Composition: 11.5–18% Cr, high carbon (0.15–2%), minimal or no nickel
- Key Properties: High hardness and strength, heat treatable, moderate corrosion resistance, and weldability requiring controlled conditions.
- Composition: Balanced mixture of austenitic and ferritic phases
- Key Properties: Approximately twice the strength of austenitic stainless steel, excellent resistance to stress corrosion cracking, good toughness, and high wear resistance.
Key Properties: High strength and corrosion resistance achieved through precipitation (age) hardening treatment, enabling excellent mechanical performance in demanding environments.
Fastener Quality Assurance, Testing & Certification
Comprehensive quality control and testing system for fasteners, ensuring compliance with international standards and certifications.
Fastener quality control covers the inspection and testing of material, dimensional, mechanical, and metallurgical properties for components such as bolts, screws, nuts, studs, rivets, washers, eyebolts, and nails. It ensures all fasteners meet required specifications and industry standards for safe and reliable industrial use.
We implement strict testing and inspection procedures, supported by detailed test reports, to verify fastener performance, strength, and consistency.
Our Quality Management System (QMS) is certified to internationally recognized standards, including ISO 9001, ISO/TS 16949, and AS 9100, ensuring controlled production, consistent quality, and compliance for industrial, automotive, and aerospace applications.
Bolt Strength Classes and Grade Specifications
Guide to selecting bolt strength grades (8.8–14.9) based on mechanical properties and application requirements
Grade 8.8 bolts are medium-strength structural fasteners commonly used in general engineering applications. They offer reliable performance for moderate load conditions and are often manufactured from carbon or alloy steel with optional corrosion-resistant coatings.
Grade 10.9 bolts provide high tensile strength of approximately 1040 MPa and are widely used in the automotive and mechanical industries. They are suitable for high-load applications such as engines and critical mechanical assemblies.
Grade 12.9 bolts are high-strength fasteners designed for demanding industrial and construction applications. They are commonly used in heavy-duty equipment, machinery, and structural assemblies requiring strong and stable fastening performance.
Grade 14.9 bolts represent ultra-high-strength fasteners with tensile strength up to 1400 MPa. They are used in extreme load conditions where maximum strength, durability, and reliability are required in critical engineering applications.
Fastener Surface Treatments and Coating Types for Corrosion Protection
Overview of fastener surface treatments designed to improve corrosion resistance, durability, and mechanical performance.
Zinc phosphate and oil is a chemical conversion coating with a thin black finish and low cost.
It provides basic corrosion protection for dry environments such as storage and indoor use, while improving lubricity.
It has very low hydrogen embrittlement risk and is widely used for general fasteners.
Zinc electroplating offers adjustable corrosion resistance and is widely used under ASTM B633 for industrial applications.
Cadmium plating provides excellent corrosion resistance and lubricity but is now mainly restricted to aerospace and military use due to environmental regulations.
Zinc flake is a non-electrolytic coating applied by dipping and curing in a zinc-rich solution.
It offers high corrosion resistance and is widely used in automotive and harsh environments, commonly under ISO 10683:2018.
It is a high-performance alternative to traditional electroplating.
Zinc-nickel electroplating provides superior corrosion resistance compared to standard zinc coatings.
It is used in automotive, heavy-duty, and high-temperature applications and is increasingly replacing cadmium.
The coating contains 12–16% nickel and requires post-bake treatment to reduce hydrogen embrittlement risk.
Custom Fastener Manufacturer Capabilities
OEM custom fastener manufacturing capabilities covering materials, sizes, head styles, and engineering designs.
We manufacture a variety of fasteners to meet your custom requirements:
- Bolts
- Screws
- Studs
- Wheel studs
Custom head designs to suit diverse applications:
- Standard heads: Hex, Round, Square, Plange bolt
- Special heads (limited to certain part numbers): T-bolts, 12-point
Precision dimensions for bolts, screws, place bolts, and wheel studs:
1.Bolts & Screws
- Diameters: M5 – M30 | ¼” – 1 ¼”
- Max lengths:
Up to 5/16” → 6”
⅜” and above → 8”
2.Place Bolts
- Diameters: M8 – M20 | ¼” – 1”
- Max lengths: same as above
3.Wheel Studs
- Diameters: M8 – M30 | 5/16” – 1 ⅛”
Our material expertise ensures durable, high-performance fasteners:
- Stainless steel (specialty focus)
- Alloy steel
- Carbon steel
How to Read Fastener Engineering Drawings (Dimensions, Threads & Specifications)
A guide to reading engineering drawings for fasteners, including dimensions, tolerances, threads, and material specifications.
Fastener Identification & Specification Details
- Title Block: Part name, part number, material grade, drawing number/revision, scale, company/drafter
- Material & Finish: Steel, stainless steel, brass, mechanical grade (e.g., 8.8, 10.9), surface treatments (zinc plating, black oxide, etc.)
- Dimensions: Length, diameter, head width/height, thread pitch, grooves or special features
- Tolerances: Acceptable deviations (e.g., +0.2 mm) and general standards like ISO 2768
- Front View: Overall shape
- Top View: Head shape and width
- Side/Section Views: Hidden features, internal threads or holes
- Thread Type: Metric (M) or Unified (UNC/UNF)
- Thread Pitch: Fine or coarse (e.g., M10 x 1.25)
- Thread Length: Portion of fastener that is threaded
Custom CNC Machining Services for Precision Parts | OEM Manufacturer Capabilities
We provide CNC machining services for precision parts with engineering support for manufacturability, scalability, and cost optimization. Send Your Drawings for Engineering Evaluation
CNC machining is limited by tool geometry, accessibility, and workpiece stiffness. Thin walls, deep cavities, and high-aspect-ratio features may vibrate or deform. Welle Fastener uses multi-axis CNC and high-rigidity fixtures to maintain precision even for complex components.
Part geometry affects manufacturability. Features like cavities, holes, threads, and thin walls must follow design guidelines. Our engineers provide DFM support to optimize designs for reliable, cost-effective CNC production.
Tolerance and part size impact cost and precision. Welle Fastener achieves standard ±0.025 mm tolerance and ±0.003 mm for critical features, with scalable capacity from prototypes to full production.
Complex features such as undercuts or deep cavities require special tooling or multi-axis machining. Welle Fastener can produce challenging geometries efficiently while advising on design improvements to enhance manufacturability.
