1/4"-20 x 3/8" Hex Bolt: High-Strength Fastening Solution for Industrial Applications

In the demanding world of industrial assembly and machinery, the integrity of every connection is paramount. Our 1/4"-20 x 3/8" hex bolt is engineered to meet these rigorous demands, offering a reliable and robust fastening solution for a multitude of applications. Designed for precision and durability, this hex head cap screw provides exceptional clamping force and shear strength, making it an indispensable component in manufacturing, construction, automotive, and machinery maintenance. This product page details the specifications, features, and advantages that make our hex bolt a superior choice for B2B procurement.

Product Overview

The 1/4"-20 x 3/8" hex bolt is a standard coarse-thread fastener characterized by a 1/4-inch nominal diameter and 20 threads per inch, with a 3/8-inch nominal length under the head. Featuring a hexagonal head for secure tool engagement, it is designed for use with a wrench or socket. This bolt is typically manufactured from high-grade steel and is available in various finishes and grades to suit specific environmental and load-bearing requirements. It is a fundamental component for creating strong, semi-permanent, or permanent joints in metal-to-metal and metal-to-wood applications.

Key Features

• High-Grade Material: Fabricated from Grade 5 or Grade 8 steel (or equivalent international standards), ensuring high tensile strength and reliable performance under stress.
• Precision Threading: Coarse UNC 1/4"-20 threads provide excellent engagement and are less prone to cross-threading, facilitating quicker assembly.
• Hexagonal Head Design: Allows for high-torque installation with standard tools, offering superior grip and reducing the risk of tool slippage and fastener damage.
• Corrosion Resistance Options: Available with various platings such as zinc, hot-dip galvanized, or black oxide to protect against rust and corrosion in diverse operating environments.
• Consistent Quality: Each 1/4 20 x 3 8 hex bolt undergoes stringent quality control checks for dimensional accuracy, thread integrity, and material properties.
• Wide Compatibility: A standard industrial size ensuring easy pairing with corresponding nuts, washers, and pre-tapped holes.

Technical Specifications

Application Scenarios

The versatility of the 1/4"-20 x 3/8" hex bolt makes it suitable for a broad spectrum of industrial and commercial applications where a compact, strong fastener is required.

• Machinery & Equipment Assembly: Used in the fabrication and repair of industrial machinery, agricultural equipment, and conveyor systems.
• Automotive & Transportation: Ideal for securing components in vehicle frames, engine brackets, and interior trim panels.
• Metal Fabrication & Construction: Essential for joining structural steel members, securing brackets, and assembling metal frames and enclosures.
• Electronics & Appliance Manufacturing: Used to secure internal chassis, panels, and components in appliances and electronic cabinets.
• General Maintenance & Repair (MRO): A staple in maintenance kits for repairing furniture, fixtures, and various mechanical assemblies.

Advantages

Choosing our 1/4 20 x 3 8 hex bolt provides distinct benefits that impact your project's efficiency, cost, and longevity.

• Enhanced Joint Integrity: The combination of coarse threading and a hex head design ensures a vibration-resistant, secure fit that maintains clamp load over time.
• Streamlined Procurement & Inventory: As a standard size, it simplifies sourcing and reduces the need for specialized inventory, lowering overall operational costs.
• Reduced Assembly Time: Easy identification and installation with common tools lead to faster production cycles and reduced labor costs.
• Long-Term Durability: With the appropriate material and finish selection, these bolts offer excellent resistance to wear, fatigue, and environmental factors.
• Cost-Effectiveness: Provides a high strength-to-cost ratio, delivering reliable performance without unnecessary expense.

Why Choose Us

As your trusted industrial fastener supplier, we differentiate ourselves through commitment to quality, service, and expertise.

• Bulk Supply Expertise: We specialize in high-volume B2B orders, offering competitive pricing and reliable supply chain logistics for your just-in-time or large-scale project needs.
• Uncompromising Quality Assurance: Our fasteners are sourced from certified manufacturers and batch-tested to ensure they meet or exceed stated industry standards.
• Technical Support: Our team provides expert guidance on material selection, corrosion prevention, and application best practices to ensure optimal performance.
• Customization & Packaging: We offer various packaging options (bulk, kit, or labeled) and can supply custom finishes or materials to meet specific project specifications.
• Global Logistics Network: Efficient worldwide shipping and export documentation ensure your order arrives on schedule, wherever your operations are located.

FAQ

What does "1/4"-20 x 3/8"" mean in a hex bolt specification?

This is the standard notation for bolt sizing. "1/4"" refers to the nominal bolt diameter. "-20" indicates there are 20 threads per inch (TPI). "x 3/8"" specifies the nominal length of the bolt, measured from under the head to the end of the shaft.

What is the difference between a Grade 5 and Grade 8 1/4 20 x 3 8 hex bolt?

Grade 5 bolts are medium-strength carbon steel bolts with a minimum tensile strength of 120,000 psi, suitable for most general applications. Grade 8 bolts are made from medium carbon alloy steel, heat-treated for higher strength (minimum 150,000 psi), and are used in high-stress, critical applications. The choice depends on the required clamp load and safety factor of your assembly.

Which finish should I choose for outdoor or corrosive environments?

For moderate outdoor exposure, zinc plating with a yellow chromate conversion coating provides good protection. For highly corrosive environments (e.g., marine, chemical), we recommend Stainless Steel 316 or Hot-Dip Galvanized finishes for superior corrosion resistance.

Can I use a nut with this bolt, or is it only for tapped holes?

The 1/4"-20 x 3/8" hex bolt is versatile. It can be used with a matching 1/4"-20 nut for through-hole applications or directly screwed into a pre-tapped hole with the same thread specification (1/4"-20 UNC).

Do you offer samples before placing a bulk order?

Yes, we encourage potential partners to evaluate our product quality. We typically provide sample kits of our 1/4 20 x 3 8 hex bolts in various grades and finishes upon request, subject to our sample policy.