Thread Repair: Notes

Special Tools

EN 42385-700 High Feature Thread Repair Kit
EN 42385-2000 Thread Insert Kit
EN 43965 Thread Repair Extension Kit

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.

Fig 1: Identifying Special Tools

Courtesy of SAAB-SCANIA OF AMERICA, INC.

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.

Fig 2: Drilling Hole Using Tap Wrench

Courtesy of SAAB-SCANIA OF AMERICA, INC.

It is critical that the drilling, counterboring and tapping of the hole to be repaired follows the same centerline as the original hole.

Fig 3: Drilling Hole On Base Material Surface

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During the drilling and tapping of the hole being repaired ensure the tooling is consistently machining perpendicular to the surface of the base material.

Fig 4: Machining Perpendicular To Base Material Surface

Courtesy of SAAB-SCANIA OF AMERICA, INC.

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