If you decide to use Helicoil's(Registered Trademark) get the entire kit. Each kit has it's own tap, which is specifically for those size inserts. Follow the instructions carefully. Use the correct drill size it recommends(very carefully), retap the hole with the included tap(again very carefully). Insert the repair coil with the breakaway tang going into the hole first. I believe the correct height for the coil is about 1/2 to 1 thread below the height of the surface. Only thing you have to be careful with is the coil jumping the thread, it happens occasionally

Breaking the tang off is optional, sometimes in blind holes it cant be broken away.

Edit........ Doc is correct(again), if done properly, the insert repair is as strong as or stronger than the original.

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