DIN 8140 is the standard cited for helical thread inserts. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
DIN 8140 — Scope
The table below lists the dimensions catalogued for helical thread inserts under DIN 8140. The scope of DIN 8140 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 8140. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by DIN 8140
| Thread size | Pitch (mm) | Length (mm) | Drill / tap size (mm) | Free coil diameter (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 4.5 | 3.1 (STI tap) | 3.45 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M3 | 0.5 | 6.0 | 3.1 (STI tap) | 3.45 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M4 | 0.7 | 6.0 | 4.2 (STI tap) | 4.57 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M4 | 0.7 | 8.0 | 4.2 (STI tap) | 4.57 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M5 | 0.8 | 7.5 | 5.3 (STI tap) | 5.67 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M5 | 0.8 | 10.0 | 5.3 (STI tap) | 5.67 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M6 | 1.0 | 9.0 | 6.3 (STI tap) | 6.80 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M6 | 1.0 | 12.0 | 6.3 (STI tap) | 6.80 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M8 | 1.25 | 12.0 | 8.4 (STI tap) | 9.01 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M8 | 1.25 | 16.0 | 8.4 (STI tap) | 9.01 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M10 | 1.5 | 15.0 | 10.5 (STI tap) | 11.26 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M10 | 1.5 | 20.0 | 10.5 (STI tap) | 11.26 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M12 | 1.75 | 18.0 | 12.6 (STI tap) | 13.51 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M12 | 1.75 | 24.0 | 12.6 (STI tap) | 13.51 | DIN 8140 / ISO 10130 | Wire thread insert, 2xD length; tang break-off |
| M16 | 2.0 | 24.0 | 16.5 (STI tap) | 17.71 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
| M20 | 2.5 | 30.0 | 20.5 (STI tap) | 22.07 | DIN 8140 / ISO 10130 | Wire thread insert, 1.5xD length; tang break-off |
Companion Standards
A complete specification for helical thread inserts normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. DIN 8140 is one of them, not all of them.
When to Specify DIN 8140
DIN 8140 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 threaded insert to this standard in a non-standard size?
Parts built to DIN 8140 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. Made by tapping or knurling.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
