For torx and torx-plus screwdriver bits, DIN 3126 C is the governing document for the dimensions listed below. Mechanical and performance requirements for this part family are set by its own standards, not by the bolt and screw property-class documents.
DIN 3126 C — Scope
The table below lists the dimensions catalogued for torx and torx-plus screwdriver bits under DIN 3126 C. The scope of DIN 3126 C itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to DIN 3126 C. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by DIN 3126 C
| Bit | Drive | Typical mating screw | Service |
|---|---|---|---|
| T10 | Torx | M3 hexalobular | electronics, appliance |
| T15 | Torx | M3.5 hexalobular | appliance, light assembly |
| T20 | Torx | M4 hexalobular | general assembly |
| T25 | Torx | M5 hexalobular | decking, general assembly |
| T27 | Torx | M5 – M6 hexalobular | construction screws |
| T30 | Torx | M6 hexalobular | structural timber screws |
| T40 | Torx | M8 hexalobular | heavy assembly |
| T20 IP | Torx security (pin-in) | M4 tamper-resistant | public and outdoor equipment |
| T25 IP | Torx security (pin-in) | M5 tamper-resistant | public and outdoor equipment |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Torx and Torx-Plus Screwdriver Bits page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 3126 C
DIN 3126 C is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
Custom manufacturing · Made to drawing
Need a fastener tool to this standard in a non-standard size?
Parts built to DIN 3126 C are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
