DIN 7504 Self-Drilling Screw Standards: Complete Reference Guide
Comprehensive guide to DIN 7504 self-drilling screw standards. Covers DIN 7504-K, 7504-N, 7504-O, and 7504-P specifications, drill point requirements, and corresponding die dimensions.
Understanding the DIN 7504 Standard Family
DIN 7504 is the German standard for self-drilling tapping screws. It defines four main types based on head style and application, each with specific drill point geometry requirements that directly determine die specifications.
For drill point die manufacturers and fastener producers, understanding DIN 7504 is essential — it's the most widely referenced standard for self-drilling screws in European, Middle Eastern, and many Asian markets.
DIN 7504 Types at a Glance
| Standard | Head Type | Drive | Primary Application |
|---|---|---|---|
| DIN 7504-K | Hex washer head | Hex socket | Metal roofing, cladding, general steel |
| DIN 7504-N | Pan head | Phillips/Pozidrive | Sheet metal assembly, HVAC, enclosures |
| DIN 7504-O | Countersunk head | Phillips/Pozidrive | Flush-mount applications, trim panels |
| DIN 7504-P | Truss/mushroom head | Phillips/Pozidrive | Large bearing surface, thin sheet overlap |
Size Designations and Dimensions
DIN 7504 uses the ST (Self-Tapping) size designation system:
| ST Size | Nominal Ø (mm) | Thread Pitch (mm) | Approximate IFI Equivalent |
|---|---|---|---|
| ST 2.9 | 2.9 | 1.3 | #4 |
| ST 3.5 | 3.5 | 1.3 | #6 |
| ST 3.9 | 3.9 | 1.3 | #7 |
| ST 4.2 | 4.2 | 1.4 | #8 |
| ST 4.8 | 4.8 | 1.6 | #10 |
| ST 5.5 | 5.5 | 1.8 | #12 |
| ST 6.3 | 6.3 | 1.8 | #14 |
Drill Point Requirements per DIN 7504
The standard specifies drill point geometry that must be achieved by the drill point die:
Point Length
The drill point length must be sufficient to clear the target material before the thread engages. DIN 7504 defines minimum point lengths based on the maximum steel thickness to be drilled:
| Drilling Capacity | Point Length (min) | Thread-Free Zone (min) |
|---|---|---|
| Up to 0.9mm steel | Short point | 2 × material thickness |
| 0.9–2.0mm steel | Medium point | 2 × material thickness |
| 2.0–5.0mm steel | Long point | 2 × material thickness |
| 5.0–12.5mm steel | Extra-long point | 2 × material thickness |
Drill Diameter
The drill point diameter (measured at the widest point of the flutes) must be larger than the screw's root diameter to create a clearance hole:
| ST Size | Screw Root Ø (mm) | Min Drill Ø (mm) | Max Drill Ø (mm) |
|---|---|---|---|
| ST 2.9 | 2.01 | 2.2 | 2.3 |
| ST 3.5 | 2.43 | 2.7 | 2.9 |
| ST 3.9 | 2.73 | 2.9 | 3.2 |
| ST 4.2 | 2.95 | 3.1 | 3.6 |
| ST 4.8 | 3.33 | 3.7 | 4.1 |
| ST 5.5 | 3.99 | 4.2 | 4.7 |
| ST 6.3 | 4.54 | 5.1 | 5.5 |
Flute Geometry
- Number of flutes: 2 (standard for all DIN 7504 types)
- Flute depth: Must allow complete chip evacuation
- Point angle: 130°–140° (not explicitly standardized but industry practice)
- Concentricity: ≤ 0.05mm TIR (total indicated runout)
Mapping DIN 7504 to ZLD Die Series
| ST Size | DIN 7504 Type | Drill Ø Range | ZLD Die Series | Die Codes |
|---|---|---|---|---|
| ST 2.9 | K/N/O/P | 2.2–2.3mm | L1 | L1-22, L1-23 |
| ST 3.5 | K/N/O/P | 2.7–2.9mm | L1 | L1-27 to L1-29 |
| ST 3.9 | K/N/O/P | 2.9–3.2mm | L1 | L1-29 to L1-32 |
| ST 4.2 | K/N/O/P | 3.1–3.6mm | L1 | L1-31 to L1-36 |
| ST 4.8 | K/N/O/P | 3.7–4.1mm | L2 | L1-37 to L1-41 |
| ST 5.5 | K/N/O | 4.2–4.7mm | L3–L4 | L1-42 to L1-47 |
| ST 6.3 | K | 5.1–5.5mm | L5–L6 | L1-51 to L1-55 |
Testing Requirements
DIN 7504 specifies performance testing for finished screws:
Drilling Performance Test
- Test plate: Steel plate of specified thickness and hardness
- Driving speed: 2,500 RPM
- Applied force: Gravity or controlled axial load
- Pass criteria: Complete penetration within specified time, no visible drill point damage
Torsional Strength Test
- Method: Apply increasing torque until failure
- Minimum torque values are specified per size:
| ST Size | Min Torsional Strength (Nm) |
|---|---|
| ST 2.9 | 1.5 |
| ST 3.5 | 2.8 |
| ST 4.2 | 5.0 |
| ST 4.8 | 7.5 |
| ST 5.5 | 12.0 |
| ST 6.3 | 18.0 |
DIN 7504 vs IFI: Key Differences
| Aspect | DIN 7504 | IFI |
|---|---|---|
| Size system | ST (metric) | # (inch-based) |
| Head types | 4 types (K/N/O/P) | Multiple types |
| Testing | DIN-specific procedures | SAE J78 |
| Market | Europe, Middle East, Asia | Americas, some Asia |
| Material grades | Per DIN 267 | Per SAE J429 |
For die manufacturers serving global markets, both standards must be supported. The drill point geometry is functionally identical — only the dimensional ranges differ slightly.
Quality Documentation
When ordering dies for DIN 7504 production, specify:
- ST size — determines drill diameter range
- Steel thickness to be drilled — determines point length
- DIN 7504 type (K/N/O/P) — affects some geometry parameters
- Material standard — DIN 267 grade for hardness requirements
- Surface finish — zinc plating, Dacromet, or other coating that adds thickness
Source DIN 7504-Compatible Dies
ZLD Precision Mold manufactures drill point dies compatible with all DIN 7504 types. Our L1–L6 series covers the complete ST 2.9 through ST 6.3 range.