Recessed Thread Repair

Fig 1: Identifying Hole Counterbore And Insert Flange

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Refer to SAFETY GLASSES WARNING .

When installed to the proper depth, the flange of the insert (1) will be seated against the counterbore (2) of the drilled/tapped hole.

1. Install a stop collar (2) on the counterbore drill (1), if required.
   Fig 2: Installing Stop Collar On Counterbore Drill

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2. NOTE:

   • During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.
   • Drill the hole until the stop collar contacts the surface of the base material.

   Drill out the threads of the damaged hole.

   Fig 3: Drilling Out Damaged Hole Threads

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3. NOTE: All chips must be removed from the drilled hole prior to tapping.

   Using compressed air, clean out any chips.

   Fig 4: Removing Drilled Hole Chips Using Compressed Air

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4. NOTE:

   • During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.
   • Ensure the tap has created full threads at least to the depth equal to the insert length.

   Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.

   Fig 5: Tapping Drilled Hole Threads Using Tapping Wrench

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5. NOTE: All chips must be removed from the tapped hole prior to insert installation.

   Using compressed air, clean out any chips.

   Fig 6: Removing Drilled Hole Chips Using Compressed Air

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6. Spray cleaner into the tapped hole. Refer to ADHESIVES, FLUIDS, LUBRICANTS, AND SEALERS  for recommended cleaner.
   Fig 7: Spraying Cleaner Into Tapped Hole

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7. NOTE: All chips must be removed from the tapped hole prior to insert installation.

   Using compressed air, clean out any chips.

   Fig 8: Removing Drilled Hole Chips Using Compressed Air

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8. NOTE: Do not allow oil or other foreign material to contact the outside diameter (OD) of the insert.

   Lubricate the threads of the driver installation tool (2) with the EN 42385-110 (1).

   Fig 9: Lubricating Driver Installation Tool Threads

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9. Install the insert (2) onto the driver installation tool (1).
   Fig 10: Installing Insert Onto Driver Installation Tool

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10. Apply threadlock sealant, EN 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2). Refer to ADHESIVES, FLUIDS, LUBRICANTS, AND SEALERS  for the recommended sealant.
    Fig 11: Applying Threadlock Sealant To Insert OD Threads

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11. Install the insert (2) into the tapped hole by hand only.
    Fig 12: Installing Insert Into Tapped Hole

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12. NOTE: If the insert will not thread down until the flange contacts the counterbored surface, remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

    Install the insert until the flange (2) of the insert contacts the counterbored surface.

    Fig 13: Installing Insert Until Flange Of Insert Contacts Counterbored Surface

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13. NOTE: The driver installation tool will tighten up before screwing completely through the insert. This is acceptable. The threads at the bottom of the insert are being formed and the insert is mechanically locking the insert into the base material threads.

    Continue to rotate the driver installation tool (1) through the insert (2).

    Fig 14: Rotating Driver Installation Tool Through Insert

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14. Inspect the insert (1) for proper installation (2) into the tapped hole.
    Fig 15: Identifying Insert Installation Position Into Tapped Hole

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15. Any installed insert that restricts or blocks an oil or engine coolant passage (3) will need to have the oil or engine coolant passage drilled out (4) to the original size of the oil or engine coolant passage. After drilling the restriction or blockage, clean out any chips and thread the installation driver tool through the insert again to remove any burrs caused by the drilling of the oil or engine coolant passage.

Fig 16: Identifying Engine Coolant Passage And Insert Installation Position

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