DIN 8140 is the standard cited for thread insert installation tools. 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
DIN 8140 specifies the dimensional requirements for thread insert installation tools.
Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for thread insert installation tools are given as limits on the individual dimensions in the table rather than as a fastener product grade.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by DIN 8140
| Tool | Step in the sequence | Sized by | Notes |
|---|---|---|---|
| STI tap | cuts the oversize thread for the insert | insert thread size | not the same as an ordinary tap of that size |
| insertion mandrel / tool | winds the insert to depth | insert thread size | sets the insert one half-pitch below the face |
| tang break-off punch | removes the driving tang | insert thread size | the tang must be removed and retrieved |
| extraction tool | removes a failed insert | insert thread size | for rework |
| key-locking insert tool | drives the keys into the parent metal | insert thread size | for key-locking inserts, not wire inserts |
Companion Standards
DIN 8140 controls only the geometry of thread insert installation tools. Surface finish is governed by separate finish standards (for example ISO 4042 for electroplating), and corrosion testing by ISO 9227 (neutral salt spray). Mechanical performance is set by the standards specific to this part family, not by ISO 898-1 or ISO 898-2, which apply to bolts, screws and nuts.
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.
