DIN 7504K vs ISO 15480: equivalent self-drilling screw standards
DIN 7504K is the legacy German designation for a hexagon washer-head self-drilling screw. It combines an external hex drive, an integral metal collar, a drill point and an ST tapping-screw thread. The screw drills suitable sheet metal and forms its own mating thread in one operation.
The practical current reference is:
DIN 7504K → ISO 15480
For Germany, the current adoption is DIN EN ISO 15480. This is the closest current counterpart, but it does not prove that every historical DIN size, drill point or commercial assembly is dimensionally identical to every ISO product.
Cross-reference status
| Reference | Relationship | Replacement status |
|---|---|---|
| DIN 7504K | Legacy German hexagon washer-head drilling screw | Historical designation |
| ISO 15480 | Hexagon washer-head drilling screw with tapping-screw thread | Closest current international counterpart |
| DIN EN ISO 15480 | German adoption of ISO 15480 | Current German reference |
| UNI 8117 | Italian counterpart for the same general family | Approximate; verify the edition and dimensions |
| JIS B1124 | Broader Japanese drilling-screw standard with modifications | Related MOD counterpart; select the relevant head type |
| ANSI/ASME | Related tapping/self-drilling references | No confirmed one-to-one equivalent |
Why DIN 7504K and ISO 15480 can be compared
Both standards describe the same basic product: a hexagon washer head, an integral bearing collar and a drilling point on an ST tapping-screw thread. That shared geometry makes ISO 15480 the correct first candidate when a legacy DIN callout must be converted.
Before approval, compare the exact ST size and length, wrench size, head height, collar diameter/thickness, drill-point form, maximum drilling capacity, material, hardness and coating. A legacy drawing may contain a point or dimensional option that is not present in the current ISO table, so the standard numbers alone are not enough.
The K form and ST thread
The K form identifies the external hexagon washer-head version within the DIN 7504 family. Do not treat an unspecified “DIN 7504 screw” as automatically being the K form.
The thread is an ST tapping-screw thread, not an ordinary ISO metric machine thread. For example, ST4.2 × 25 is not an M4.2 machine screw. Specify the complete ST designation, length and point design.
Concrete differences that affect interchangeability
The product concept is close, but these are the differences that must be resolved in purchasing:
| Check point | DIN 7504K legacy callout | ISO 15480 / current product | Why it matters |
|---|---|---|---|
| Form | K hexagon washer head | Hexagon washer head | A different DIN 7504 form changes the head/drive |
| Thread | ST tapping-screw sizes | ST tapping-screw sizes | ST is not M-thread; pitch and forming behavior differ |
| Point | Legacy tables and catalogues may list different point options | Current ISO table controls point geometry and range | Drilling capacity can change even at the same ST diameter |
| Head/collar | Historical dimensions may vary by edition or supplier | ISO dimensions and tolerances apply | Wrench access, bearing area and washer fit can change |
| Material/finish | Not determined by the number alone | Must be specified with the order | Hardness and coating control drilling and corrosion |
| Sealing washer | Not inherent in the bare screw designation | Often supplied as a separate assembly option | EPDM/neoprene sealing is not the same as a metal collar |
Drilling performance depends on drill-point geometry, steel grade and hardness, total material stack, installation speed/torque and driver alignment. A supplier’s drilling-capacity table is product data, not a universal guarantee of the standard.
UNI 8117
UNI 8117 is useful as a close Italian purchasing reference for this general hexagon-head self-drilling family. The relationship is approximate, not unconditional identity. Compare ST size, pitch, wrench size, collar diameter, head height, point length, drilling capacity, material, hardness and coating. For new international specifications, ISO 15480 or DIN EN ISO 15480 is the clearer current route.
JIS B1124
JIS B1124 is broader than ISO 15480. It covers several Japanese drilling-screw head types and contains Japanese modifications or additional requirements. Therefore, JIS B1124 alone does not identify the hexagon washer-head section corresponding to DIN 7504K.
For a proposed JIS replacement, confirm the relevant head form, ST size and length, collar/washer dimensions, drill-point capacity, material and surface treatment. Do not describe every JIS B1124 item as identical to ISO 15480.
ANSI/ASME references
Do not map DIN 7504K directly to ASME B18.6.3, SAE J78 or a commercial “Tek” point number. ASME B18.6.3 covers many tapping-screw configurations and does not by itself define the metric DIN/ISO self-drilling product. US products may use Unified inch threads, different point classifications and different head/collar tables.
Collar, sealing washer, material and coating
The integral metal collar spreads bearing load. It is not automatically an EPDM or neoprene sealing washer. Keep these executions separate:
- bare DIN 7504K / ISO 15480 screw;
- screw with an assembled metal washer;
- screw with an EPDM or neoprene sealing washer.
Material and heat treatment are product requirements, not facts implied by DIN 7504K. Request the supplier’s material, hardness, drilling-capacity and corrosion data for demanding applications.
Replacement decision
| Proposed replacement | Decision |
|---|---|
| DIN 7504K → ISO 15480 | Closest current counterpart; verify the exact legacy point and dimensions |
| DIN 7504K → DIN EN ISO 15480 | Current German adoption; verify edition and product details |
| DIN 7504K → UNI 8117 | Approximate Italian relation; compare the complete dimensional and performance data |
| DIN 7504K → JIS B1124 | Related broader MOD standard; identify the hexagon washer-head section |
| DIN 7504K → ASME B18.6.3 | Not a direct self-drilling equivalent |
Procurement checklist
- State the standard and edition, preferably ISO 15480 / DIN EN ISO 15480 for new work.
- State the exact
Kform, ST size and nominal length. - Confirm wrench size, collar dimensions and point type.
- State the complete material stack and required drilling capacity.
- Specify material, hardness, coating and corrosion resistance.
- Specify EPDM/sealing washer details separately, if required.
- For UNI or JIS proposals, identify the applicable edition and dimensional table.
A complete RFQ is clearer than DIN 7504K screw alone, for example: ISO 15480 reference, hexagon washer head, ST4.8 × 25, drilling capacity for 1.75–4.4 mm steel stack, zinc plated, EPDM washer if required.
