Large Flat Head Self-Drilling Screws - China Suppliers & Factory - 304 Stainless Steel & Carbon Steel Options

Introducing our Large Flat Washer Head Phillips Self-Drilling Tek Screw, an essential component for various construction and assembly applications. Manufactured from high-quality 304 Stainless Steel and Premium Carbon Steel, these screws meet rigorous standards such as GB/T 15856.2 and DIN 7504N, underscoring our commitment to quality as a trusted supplier and factory based in China.

We offer an extensive range of grades, including Carbon Steel grades 4.8 and 8.8 (high strength) and Stainless Steel grade A2-70 (304), ensuring you find the perfect fit for your projects. Available specifications include sizes M3.5, M4.2, M4.8, M5.5, M6.3, and lengths ranging from 13mm to 150mm, with customization options to meet specific needs.

Our screws feature a unique design with a self-drilling tin can tip, an integrated large flat-head flange, a cross-groove drive, high-strength anti-slip threads, and dual-material corrosion resistance, perfect for various applications. Ideal for steel structure buildings, color steel tile installations, light steel keels, electromechanical equipment assembly, and HVAC engineering, these screws are versatile enough for furniture and wood product modifications.

We provide flexible delivery timelines of 15-30 days upon receipt of advance payment. Our minimum order quantity is 10,000 pieces, with negotiable terms available. Samples are readily provided for your assessment. Choose from multiple packaging options, including boxed, bulk, pallet, or customized solutions. OEM services are also available to further cater to your specifications.

Trust our reliable factory in China for high-quality self-drilling screws that meet your construction or manufacturing needs.

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Key Features

Our self-tapping screws are crafted from food-grade 304 stainless steel and treated to achieve metric Grade 12.9 ultra-high strength, overcoming the traditional hardness limitations of standard stainless steel. Featuring a countersunk Phillips head design, these screws can be installed flush with the workpiece surface for a zero-profile finish, making them ideal for precision electronics and architectural decoration. We have optimized the thread geometry for different substrates (metal, wood) to ensure low-torque driving with high-torque clamping, effectively preventing stripping. As a superior alternative to standard Tek screws, these fasteners perform exceptionally well in thin sheet metal connections, providing an intelligent fastening solution that balances aesthetics with high load-bearing capacity.

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Precision Manufacturing Process

From wire rod to finished product, we strictly adhere to multiple international standards including ISO, DIN, ANSI, and GB. Utilizing multi-station cold forging technology, we ensure shank diameter tolerances are controlled within microns. Threads are formed through a precision thread rolling process to enhance fastening force. For non-standard requirements, we employ optical imaging sorters to reject minute defects like head cracks. In post-treatment, we offer a wide range of surface finishing options: from conventional zinc plating and nickel plating to highly corrosion-resistant Hot-Dip Galvanizing (H.D.G.), as well as decorative polishing and black anodizing. We even provide food-grade passivation treatment, ensuring every screw has a prolonged fatigue life in demanding environments.

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Transparency & Customization

As a source factory, we are committed to breaking down the information barriers of traditional trade. From mill certificates for raw materials to hardness grades (covering Grade 4.8 to Grade 12.9, as well as A2-70 and A4-80 marine-grade stainless steel), all test data is traceable. We support full-chain customization: dimensionally, we can adjust thread length and head thickness according to drawings; functionally, we can combine processes like sandblasting, electrophoretic coating (e-coating) , or chrome plating. Whether you need British Standard (BS) fasteners or require a special colored anodized finish, we offer small-batch sampling. This ensures that when you purchase fasteners from us, you not only receive high-quality products but also full transparency and control over the entire process, from material selection to packaging.

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No Pre-Drilling · Rust Resistant · More Secure

This stainless steel Phillips countersunk self-tapping screw, with its rust-resistant and corrosion-resistant material, one-step self-tapping design, and aesthetically pleasing countersunk head structure, has become the preferred solution for metal substrate fastening scenarios that is efficient, reliable, and aesthetically pleasing.

Product Details

Manufacturing Process

Multi Station Cold Heading Technology
Intelligent Heat Treatment System
Micron-Level Thread Rolling Process
Fully Automatic Optical Sorting
Environmentally Friendly Surface Treatment Line
Metallographic And Mechanical Joint Laboratory

Quality Control System

Raw Material Source Locking
Furnace Number Batch Full Traceability
Third Party Material Certification
Process Parameters Open And Transparent
Salt Spray Test Real Time Monitoring
International Standard Compliance Declaration

Flexible Customization Capability

Customizable head/slot Shapes
Extreme Application Of Special Materials
Breakthroughs In Extra Large/Long Specifications
Integrated Assembly Of Components
Customizable Surface Treatment Colors
Personalized Packaging And Labeling

Technical Service

On-Site Failure Analysis
Selection Calculation And BOM Optimization
Installation Tool Selection Guidance
Inventory Management (VMI) Trusteeship
Free Sample Making And Testing
International Standard Translation And Interpretation

Self-Drilling Tip – No Pre-Drilling, Efficient One-Step Installation

The built-in self-drilling tip penetrates steel sheets, light-gauge steel studs, metal panels, and aluminum profiles directly – no pre-drilling or punching needed. With an electric driver, drilling, tapping, and fastening are completed in a single step – several times faster than ordinary self-tapping screws. Ideal for large roofing, ductwork, and drywall framing projects – significantly reducing construction time and labor costs.

One-Piece Large Flat Washer Head + Anti-Slip Ribs – Load Distribution & Anti-Loosening

The integrated large flat washer head offers far greater bearing area than countersunk or pan head screws, effectively preventing depression, deformation, or cracking of thin panels or soft substrates during tightening. The bottom face features dense anti-slip ribs that bite into the workpiece surface, creating mechanical locking against vibration and impact loosening – particularly suitable for steel roofing, equipment housings, and electrical box assemblies, staying secure for years.

Dual-Material Corrosion Protection + Hardened Threads – Heavy-Duty & Durable

304 stainless steel with electro-polishing/passivation resists moisture, rain, and salt spray – ideal for outdoor, coastal, and chemical environments; carbon steel with blue-white/yellow zinc plating offers reliable indoor corrosion protection. Hardened threads and wear-resistant drill tips resist stripping even after repeated use. Fatigue-tested, this screw withstands long-term wind loads, vibration, and temperature changes without failure – extremely low replacement frequency, delivering outstanding cost-performance.

Factory Environment

High-Quality Stainless Steel Self-Tapping Screw Display

Frequently Asked Questions

Do these self-drilling screws require pre-drilling?

No, the built-in self-drilling tip penetrates steel sheets, light-gauge steel studs, metal panels, and aluminum profiles directly. Drilling, tapping, and fastening are completed in a single step without pre-drilling.

How does the flat washer head prevent loosening?

The integrated large flat washer head provides a larger bearing area to prevent deformation or cracking of thin panels. Additionally, the bottom face features dense anti-slip ribs that bite into the surface to prevent loosening caused by vibration and impact.

What materials and corrosion protection options are available?

We offer 304 stainless steel with electro-polishing/passivation for outdoor, coastal, and chemical environments, as well as carbon steel with blue-white or yellow zinc plating for reliable indoor corrosion protection.

Can I customize the head shape and specifications of the screws?

Yes, we provide flexible customization capabilities including customizable head/slot shapes, extreme application of special materials, extra large or extra long specifications, integrated component assembly, customizable colors, and personalized packaging.

What quality control systems do you have in place?

Our quality control system includes raw material source locking, furnace number batch full traceability, third-party material certification, transparent process parameters, real-time salt spray test monitoring, and international standard compliance declarations.

What technical services and support do you provide?

We support our clients with on-site failure analysis, selection calculation and BOM optimization, installation tool selection guidance, inventory management (VMI) trusteeship, free sample making and testing, and international standard translation and interpretation.