The DIN 7504-K self-drilling screw is a hex washer head fastener developed for drilling and fastening suitable sheet or plate material in one installation operation. DIN 7504-K:1995 is a withdrawn German trade designation; its product form was carried forward into DIN EN ISO 15480, whose current 2019 edition covers steel hexagon washer head drilling screws with tapping screw threads from ST2.9 to ST6.3. The integral drill point forms the hole before the tapping thread engages, while the flanged hex head provides an external wrenching surface and a broad bearing area.
Product Overview and Key Features
The K form combines a drilling point, tapping screw thread, external hex drive, and washer-style bearing flange in one fastener.
- Integrated drilling point: prepares the hole during installation before the tapping thread forms its mating thread.
- Hex washer head: provides positive external tool engagement and a larger bearing surface than many smaller-head screw styles.
- ST tapping thread: current ISO 15480 sizes use ISO 1478 tapping screw threads.
- Controlled drilling range: each thread size has a defined sheet or plate thickness range rather than one universal capacity.
DIN 7504-K Self-Drilling Screw Specifications
Specification Overview
| Item | Specification |
|---|---|
| Trade designation | DIN 7504-K:1995, withdrawn |
| Current successor | DIN EN ISO 15480:2019 / ISO 15480:2019 |
| Product form | Hexagon washer head drilling screw with tapping screw thread |
| Current thread range | ST2.9, ST3.5, ST4.2, ST4.8, ST5.5, ST6.3 |
| Thread reference | ISO 1478 |
| Material in current standard | Steel |
| Product grade | A |
| Mechanical/function reference | ISO 10666 |
| Common market configurations | Case-hardened carbon steel; zinc-plated or other specified coatings; optional sealing washer for suitable applications |
Dimensions and Thread Details
The following values use the current ISO 15480 successor dimensions. P is thread pitch, dc is washer-head flange diameter, s is width across flats, and k is head height. Dimensions and drilling ranges are in millimetres.
| Thread | P (mm) | dc Min-Max (mm) | s Min-Max (mm) | k Min-Max (mm) | Drilling Range (mm) |
|---|---|---|---|---|---|
| ST2.9 | 1.1 | 5.8-6.3 | 3.82-4.00 | 2.5-2.8 | 0.7-1.9 |
| ST3.5 | 1.3 | 7.6-8.3 | 5.32-5.50 | 3.0-3.4 | 0.7-2.25 |
| ST4.2 | 1.4 | 8.1-8.8 | 6.78-7.00 | 3.6-4.1 | 1.75-3.0 |
| ST4.8 | 1.6 | 9.8-10.5 | 7.78-8.00 | 3.8-4.3 | 1.75-4.4 |
| ST5.5 | 1.8 | 10.0-11.0 | 7.78-8.00 | 4.8-5.4 | 1.75-5.25 |
| ST6.3 | 1.8 | 12.2-13.5 | 9.78-10.00 | 5.3-5.9 | 2.0-6.0 |
The older DIN 7504-K table also included ST3.9, which is not listed in current ISO 15480:2019. If a legacy drawing specifies ST3.9, retain that designation in the RFQ instead of automatically converting it. Nominal length must also suit the total sheet stack, any air gap, required thread engagement, and drilling-point clearance.
Common Materials, Grades and Surface Finishes
Material and Grade Options
Current ISO 15480 specifies steel and references ISO 10666 for mechanical and functional properties. Case-hardened carbon steel such as C1018 or C1022 is a common market configuration. Stainless and bi-metal self-drilling screws are also sold for corrosion-sensitive applications, but they should be specified to their applicable material and performance requirements rather than assumed to be standard DIN 7504-K steel.
Coating and Finish Options
ISO 15480 permits as-processed steel, electroplated coatings to ISO 4042, or other finishes agreed between supplier and purchaser. Zinc plating and specified zinc-flake systems are common market options. Hardened steel screws require suitable process control for hydrogen-embrittlement risk. EPDM sealing washers are frequently paired with hex washer head drilling screws for roofing or cladding, but the sealing washer is an application option, not a mandatory DIN 7504-K feature.
Typical Applications and Selection Considerations
- Metal roofing and wall cladding attached to suitable steel supports.
- HVAC ducting, sheet-metal brackets, and light fabricated frames.
- Electrical enclosures, cabinets, covers, and equipment panels.
- General metal-to-metal fastening where the drilling capacity matches the joint stack.
Flybear’s sheet-metal screw RFQ guide explains the difference between tapping and drilling screws. Match the drilling range to the actual combined thickness and material. For roofing and secondary steelwork, see the steel construction fastening guide. A separate bonded sealing washer should be specified when weather sealing is required.
Ordering and Quality Documentation
An RFQ should state DIN 7504-K or ISO 15480, thread size, nominal length, material, coating, quantity, drilling thickness, mating material, and whether a sealing washer is required. Inspection can address dimensions, thread and point geometry, hardness, drilling performance, and coating. Flybear’s quality control and inspection page provides related inspection information; exact documents and test scope should be agreed for the order.
Frequently Asked Questions
Is DIN 7504-K still a current DIN standard?
No. DIN 7504-K:1995 was withdrawn and its hex washer head drilling screw form was superseded by DIN EN ISO 15480. The current DIN EN ISO 15480:2019 edition corresponds to ISO 15480:2019. DIN 7504-K nevertheless remains widely used as a commercial product description.
What sizes replace the old DIN 7504-K range?
Current ISO 15480 lists ST2.9, ST3.5, ST4.2, ST4.8, ST5.5, and ST6.3. The older DIN table also contained ST3.9. Buyers working from legacy drawings should quote the exact DIN size rather than assuming that ST3.9 can be substituted without reviewing the joint.
Does a DIN 7504-K screw need a pilot hole?
Normally, the integrated drilling point is intended to create the hole during installation within its specified drilling range. Performance still depends on material type, thickness, drill-point geometry, installation speed, and tooling. Applications outside the drilling capacity may require another screw design.
Can DIN 7504-K screws be supplied with an EPDM washer?
EPDM bonded sealing washers are a common market addition for roofing and exterior cladding because they can help seal the fastener penetration when correctly selected and installed. They are not a mandatory feature of the basic standard, so washer diameter, material, and sealing requirement should be stated separately.
What should I include in a quotation request?
Provide the standard designation, ST thread size, screw length, material, finish, quantity, sheet or plate material, total drilling thickness, and any sealing washer requirement. Include a drawing when point geometry, nonstandard length, head dimensions, coating, or application-specific inspection requirements differ from the standard product.
Request a Quote for DIN 7504-K Self-Drilling Screws
For a DIN 7504-K self-drilling screw quotation, send Flybear Industrial the thread size, length, material, coating, quantity, drilling thickness, mating material, and sealing washer requirements. Include drawings for legacy ST3.9 or project-specific configurations. Submit the details through the Flybear fastener RFQ page for technical review and quotation.
