Hex Head Self-Drilling Screw With Washer 5.5x25mmZinc-coated hex head self-drilling screw with EPDM washer. No pre-drilling required. Suitable for metal roofing, cladding, fence panel installation and steel frame construction.MaterialCarbon SteelFinishZinc CoatMOQ500 pcsLead time15-30 daysKey FeaturesSelf-drilling TEK tip eliminates pre-drilling - saves time and laborIntegrated EPDM washer provides weatherproof sealing for outdoor useZinc coating for superior corrosion resistance in harsh environmentsHex head design for easy installation with standard socket or wrenchHigh tensile strength suitable for heavy-duty metal-to-metal fasteningAvailable in gray and brown to match roofing and cladding materialsCustom sizes available: 5.5mm and 6.3mm diameter, 25-75mm lengthsISO9001 certified, CE and FDA approved quality managementTechnical SpecificationsSpecificationValueHead TypeHex Head with EPDM WasherDrive TypeHex SocketPoint TypeSelf-Drilling (TEK)Thread TypeCoarse ThreadMaterialCarbon SteelSurface TreatmentZinc Coat (Zinc White, Natural Color)Color OptionsGray, BrownStandard Sizes5.5x25mm, 5.5x32mm, 5.5x38mm, 5.5x50mm, 5.5x65mm, 5.5x75mm; 6.3x25mm, 6.3x32mm, 6.3x38mm, 6.3x50mm, 6.3x65mm, 6.3x75mmPlace of OriginZhejiang, ChinaBrandST (HST)Warranty1 YearSampleAvailableCustomizationOEM/ODM acceptedPackage Size33x33x18 cmGross Weight20 kg per packageProduct DescriptionHST's Hex Head Self-Drilling Screw With Washer is engineered for fast, reliable fastening in metal roofing, cladding, fence panels, and steel frame construction. The self-drilling (TEK) tip bores through metal without pre-drilling, saving significant installation time and labor costs. The integrated EPDM rubber washer provides a weatherproof seal that prevents water ingress at the fastening point - critical for outdoor roofing and cladding applications. The zinc coating delivers superior corrosion resistance, ensuring long service life even in harsh outdoor environments. Available in gray and brown colors to match common roofing and cladding materials. Custom sizes and colors are available upon request. All products are manufactured under ISO9001 quality management standards and carry CE and FDA certifications.Typical ApplicationsMetal roofing and cladding installationSteel frame construction and structural fasteningFence panel installation on steel postsIndustrial and commercial building constructionPurlins and girts fasteningCorrugated iron sheet fasteningFAQWhat is the difference between self-drilling and self-tapping screws?Self-drilling screws (TEK screws) have a drill-bit tip that can bore through metal without pre-drilling, while self-tapping screws require a pre-drilled pilot hole. Our hex head screws are self-drilling, making them faster and easier to install.Are these screws suitable for outdoor use?Yes. The zinc coating provides excellent corrosion resistance, and the integrated EPDM washer creates a weatherproof seal at the fastening point, making these screws ideal for outdoor roofing, cladding, and fence applications.What sizes are available?Standard sizes include 5.5mm and 6.3mm diameter, with lengths from 25mm to 75mm (25, 32, 38, 50, 65, 75mm). Custom sizes are available upon request with OEM/ODM service.What is the minimum order quantity?The MOQ is 500 pieces for standard sizes. Custom orders may have different MOQ requirements. Please contact us for bulk pricing and custom specifications.Can I get samples before placing a bulk order?Yes, samples are available. Please contact our sales team to request samples. Lead time for bulk orders is typically 15-30 days after order confirmation.Can I request alternative coatings or materials for these self-drilling screws to meet specific salt spray resistance requirements?Yes, HST offers several finish options including Ruspert 1000-hour coating, mechanical galvanizing, and color-matched powder coating to align with specific RAL fence or roofing panels. For projects requiring maximum durability, we also produce these screws in Bi-metal (304/316 stainless steel body with a carbon steel drilling point) to provide both high corrosion resistance and the necessary hardness for penetrating structural steel.Can HST provide custom head painting and specific corrosion-resistant coatings for these 5.5x25mm self-drilling screws?We offer comprehensive OEM services for these screws, including precision head painting matched to your specific RAL color codes to ensure a seamless finish with your fence or roofing panels. Beyond aesthetics, we can customize technical specifications such as increasing the zinc plating thickness for high-salinity environments or providing specialized EPDM washer diameters for superior waterproofing. We also support private labeling and custom bulk packaging configurations to meet your specific distribution and branding requirements.Request a quote from HST