Thread Repair: Notes
Special Tools
- EN - 42385-70 Head Bolt Thread Repair Fixture
- EN - 42385-700 High Feature Thread Repair Kit
- EN - 42385-2000 Thread Insert Kit
- EN - 43965 Thread Repair Extension Kit
For equivalent regional tools, refer to Special Tools .
The thread repair process involves a solid, thin walled, self-locking, carbon steel, bushing type insert. During the insert installation process, the installation driver tool cold-rolls the bottom internal threads and expands the bottom external threads of the insert into the base material. This action mechanically locks the insert into place.
The drill bit and counter bore tool from the tool kit EN - 42385-700 kit and EN - 42385-2000 insert kit is designed for use with either a suitable tap wrench or drill motor. Limited access and larger hole repair may process better using a tap wrench. An extension from kit EN - 43965 extension kit may also be necessary to drive the thread repair tooling dependent on access to the hole being repaired. Use only a tap wrench when tapping the hole and during installation of the insert.
It is critical that the drilling, counterboring and tapping of the hole to be repaired follows the same centerline as the original hole.
During the drilling and tapping of the hole being repaired ensure the tooling is consistently machining perpendicular to the surface of the base material.
If the threaded hole being repaired has a base surface perpendicular to the hole centerline, tapping guides are available to aid in tapping the hole.
| Tap Size | Tap Guide | Tap Size | Tap Guide | Tap Size | Tap Guide |
|---|---|---|---|---|---|
| - | EN 42385- | - | EN 42385- | - | EN 42385- |
| 6 x 1.0 | 729 | 10 x 1.5 | 731 | 14 x 1.5 | 736 |
| 8 x 1.25 | 730 | 12 x 1.5 | 732 | 20 x 1.5 | 737 |