--- title: "What Are Cross Flat-Head Knurled Self-Tapping Screws Used For?" description: "Cross Flat-Head Knurled Self-Tapping Screws (GB/T 845 / DIN 7981 / GB/T 5267.1) are used for fixing into sheet, timber or plastic by forming their own thread…" url: https://engineeringhardware.com/applications/cross-flat-head-knurled-self-tapping-screws/ source: Engineering Hardware & Fasteners --- # What Are Cross Flat-Head Knurled Self-Tapping Screws Used For? Screws · GB/T 845 / DIN 7981 / GB/T 5267.1 · Application guide Typical applications, the industries that specify cross flat-head knurled self-tapping screws, and how to choose the right size, material and finish for the joint. Cross Flat-Head Knurled Self-Tapping Screws are used for fixing into sheet, timber or plastic by forming their own thread as they are driven, without a tapped hole. They are manufactured to GB/T 845 / DIN 7981 / GB/T 5267.1, and selection is driven by the size designation, the fit and tolerance the assembly requires, and the service environment. - **Primary duty:** Fixing into sheet, timber or plastic by forming their own thread as they are driven, without a tapped hole - **Governing standard:** GB/T 845 / DIN 7981 / GB/T 5267.1 - **Category:** Screws Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are Cross Flat-Head Knurled Self-Tapping Screws Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/09/Cross-Flat-Head-Knurled-Self-Tapping-Screws.webp) Cross Flat-Head Knurled Self-Tapping Screws are used primarily for fixing into sheet, timber or plastic by forming their own thread as they are driven, without a tapped hole. This page lists the industries and assemblies where they are specified, the selection criteria that matter for each application, installation practice, and the cases where a different fastener type is the correct choice. Parts are supplied to GB/T 845 / DIN 7981 / GB/T 5267.1. ## Typical Applications for Cross Flat-Head Knurled Self-Tapping Screws The most common settings where these are specified: - **Machine guarding & panels:** removable access covers that are opened for service. - **General machine building:** fastening covers, brackets, motors and sub-assemblies on production equipment. - **Maintenance & repair (MRO):** a stocked size for servicing existing plant where the original fastener spec must be matched. - **Fabrication & metalwork:** bench and on-site assembly of steel frames, enclosures and weldments. - **Electronics & enclosures:** mounting PCBs, panels and lids where the drive style and head height matter. 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Quoting the standard on your order guarantees interchangeable dimensions between suppliers. ## Installation & Assembly Practice - Match the driver exactly to the recess (PH ≠ PZ; hex key sizes per ISO 2936) and keep the tool axial — side load is the main cause of stripped drives. - In tapped holes, engage a thread length of at least 1× the nominal diameter in steel, 2× in aluminum. - Set power tools to a torque that seats the head without embedding it into the mating surface. ## Common Selection Mistakes with Cross Flat-Head Knurled Self-Tapping Screws - Under-sizing the drive for the installation torque — a small recess at high torque strips before the screw is seated. - Using a countersunk head in thin sheet where the countersink removes most of the load-bearing material. - Specifying stainless in high-strength duty: A2-70 is roughly class 7 steel, not a 10.9 substitute. ## Where Cross Flat-Head Knurled Self-Tapping Screws Are Not the Right Choice Not for high-preload structural joints (use a property-class bolt and nut), and not in thin sheet where a self-drilling or self-tapping type suits better. Custom manufacturing · Made to drawing ## Need a cross flat-head knurled self-tapping screws outside the standard range? Dimensions, material, finish and form are specified from the drawing — a screw outside the standard range is a variation on existing tooling rather than a new design. Made by cold heading or warm forging. Minimum order from 2,000 pieces; samples within 7 days of drawing approval. [Custom screw manufacturing](https://engineeringhardware.com/custom/screws/)[Send a drawing](https://engineeringhardware.com/custom/screws/#rfq) ## Technical Drawing Dimensioned line drawing of cross-recess flat head Cross Flat-Head Knurled Self-Tapping Screws to GB/T 845 / DIN 7981 / GB/T 5267.1. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Under-head feature:** under-head knurling - **Material:** carbon steel - **Finish options:** zinc plating - **Substrate:** wood ## Dimensions & Specifications (GB/T 845 / DIN 7981 / GB/T 5267.1) | Head form | Under-head feature | Material | Finish options | Substrate | | --- | --- | --- | --- | --- | | cross-recess flat head | under-head knurling | carbon steel | zinc plating | wood | | cross-recess flat head | under-head knurling | carbon steel | colour zinc plating | plastic | | cross-recess flat head | under-head knurling | carbon steel | black oxide | thin plate | Inside the plant ## Manufactured in our own plant This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided. 1. ![Wire rod feeding into a cold heading machine](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 01 **Cold heading** Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail. Head dimensions and under-head radius checked at set-up and per shift. 2. ![Thread rolling machine producing bolt threads](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 02 **Thread rolling** Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch. Go / no-go ring gauges to ISO 965 tolerance class 6g. 3. ![Baskets of bolts staged for heat treatment](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 03 **Heat treatment** Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it. Core hardness and tensile tested per lot to ISO 898-1. 4. ![Zinc plated bolts in a treatment basket](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 04 **Surface treatment** Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list. Coating thickness and neutral salt spray hours to ISO 9227. ## Frequently Asked Questions ### Are Cross Flat-Head Knurled Self-Tapping Screws made to a recognized standard? Yes — they are manufactured to GB/T 845 / DIN 7981 / GB/T 5267.1, so dimensions are interchangeable between suppliers when you quote the standard on your order. ### What are Cross Flat-Head Knurled Self-Tapping Screws used for? Fixing into sheet, timber or plastic by forming their own thread as they are driven, without a tapped hole. They are supplied to GB/T 845 / DIN 7981 / GB/T 5267.1. ### Which industries use Cross Flat-Head Knurled Self-Tapping Screws? They are commonly specified in electronics & enclosures, appliances & consumer goods and machine guarding & panels, among other sectors. ### How do I choose the right size of Cross Flat-Head Knurled Self-Tapping Screws? Match the size to the mating part using the dimension table on this page. ### Can I get a quote for Cross Flat-Head Knurled Self-Tapping Screws in the size and material I need? Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time. ## Related Pages Product page: [Cross Flat-Head Knurled Self-Tapping Screws — specifications & sizes](https://engineeringhardware.com/fastener/cross-flat-head-knurled-self-tapping-screws/) ### Cross Flat-Head Knurled Self-Tapping Screws Specification Guides ### Related Fastener Applications