How to Repair Broken Threads (Largus 1)

Sometimes the internal threads of nuts or bolt holes become damaged, usually from overtightening. Thread stripping is a very common occurrence, especially when working with aluminum parts, since aluminum is so soft that it strips easily. Overtightened spark plugs are another common cause of thread damage.

Typically, the external or internal thread is only partially stripped. After cleaning it with a tap or lap, it continues to work. Sometimes, however, the threads are seriously damaged. If this happens, you have two options to choose from:

1. Drill a hole the next larger size, tap it, and install a larger bolt, screw, or stud.



2. Drill a hole and tap a thread to accept the plug, then drill the plug and tap a thread to the original size. You can also buy a plug already with the original thread size cut into it. Then you just need to drill a hole to the required size, and then install a threaded plug into this hole using a bolt and lock nut. Once the plug is fully seated, remove the lock nut and bolt.

No matter what method you use, work calmly and carefully. A little impatience or carelessness while performing one of these relatively simple procedures can ruin a whole day's work and be costly if you damage an expensive part.